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  • 1. Aaltonen, Olli
    et al.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Peltola, Maija S.
    Savela, Janne
    Tamminen, Henna
    Lehtola, Heidi
    Brain responses reveal hardwired detection of native-language rule violations2008Ingår i: Neuroscience Letters, ISSN 0304-3940, E-ISSN 1872-7972, Vol. 444, nr 1, s. 56-59Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mismatch negativity (MMN) is a neural correlate of the preattentive detection of any change in the acoustic characteristics of sounds. Here we provide evidence that violations of a purely phonological constraint in a listener's native language can also elicit the brain's automatic change-detection response. The MMN differed between Finnish and Estonian listeners, conditions being equal except for the native language of the listeners. We used two experimental conditions: synthetic vowels in isolation and the same vowels embedded in a pseudo-word context. MMN responses to isolated vowels were similar for Finns and Estonians, while the same vowels in a pseudoword context elicited different MMN patterns depending on the listener's mother tongue.

  • 2.
    Ahola, Angela S.
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Christianson, Sven Å.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Justice Needs a Blindfold: Effects of Gender and Attractiveness on Prison Sentences and Attributions of Personal Characteristics in a Judicial Process2009Ingår i: Psychiatry, Psychology and Law, ISSN 1321-8719, E-ISSN 1934-1687, Vol. 16, nr 1, s. 90-100Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study examined the effect of gender and facial characteristics of criminal offenders on attributions of crime-relevant traits. The stimulus pictures portrayed women and men of varying attractiveness. Participants were presented with pictures of these female or male faces along with accompanying crime accounts. The crime account described the individual in the picture as a person who had committed one of the following crimes: theft, fraud, drug crime, child molestation, child abuse, or homicide. After reading one case account the participants were asked to evaluate the credibility and other crime-relevant personality traits of the offender. Results showed that female defendants were rated more favourably than were male defendants. Gender worked to the advantage of the female perpetrator. There were also slight tendencies towards more lenient appraisal of the more attractive women.

  • 3.
    Ahola, Angela S.
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Is Justice Really Blind?: Effects of Crime Descriptions, Defendant Gender and Appearance, and Legal Practitioner Gender on Sentences and Defendant Evaluations in a Mock Trial2010Ingår i: Psychiatry, Psychology and Law, ISSN 1321-8719, E-ISSN 1934-1687, Vol. 17, nr 2, s. 304-324Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two experiments were conducted to investigate how sources of information can bias the judicial process. Experiment 1 investigated the effects of photographs of victims’ injury, and of vivid verbal victim injury description, on the evaluation and sentencing of a defendant in a mock criminal trial. The participants were presented with five different crime accounts: (a) vandalism, (b) arson, (c) child abuse, (d) child molestation, and (e) homicide, all committed by male perpetrators, and were asked to evaluate the trustworthiness, culpability, aggressiveness, guilt, and other crime-relevant personality traits of the defendant, and to set imprisonment sentences. Results of Experiment 1 showed that exposure to photographs of crime victim injuries as well as vivid crime descriptions had only weak and non-significant effects on defendant evaluations, but imprisonment terms tended to be longer in the Photo condition than in the No photo condition. To further investigate the possible effects of photographic information on judicial processes for different crimes (child molestation, child abuse, homicide), Experiment 2 was conducted with legal practitioners (judges, members of Swedish juries, law students, counsels for the defence, prosecutors, police officers) as evaluators. Results showed three tendencies: (a) a ‘‘same-sex penalty effect’’: sentencing evaluators (judges, jurors) evaluated a defendant of the same gender as the evaluator, more harshly than one of the opposite gender, (b) a ‘‘male penalty effect’’: non-sentencing evaluators (police officers, counsels for the defence, prosecutors, and law students) evaluated and judged a male defendant more harshly than a female, and (c) for female non-sentencing evaluators, the male penalty effect was enhanced for the more attractive defendants. Overall, the results suggest that defendant gender, defendant appearance, evaluator gender, and evaluator profession can affect the outcome of a criminal trial.

  • 4. Dåderman, Anna M.
    et al.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen, Perception och psykofysik.
    Interrater Reliability of Psychopathy Checklist–Revised: Results on Multiple Analysis Levels for a Sample of Patients Undergoing Forensic Psychiatric Evaluation2018Ingår i: Criminal justice and behavior, ISSN 0093-8548, E-ISSN 1552-3594, Vol. 45, nr 2, s. 234-263Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Scores from the Psychopathy Checklist–Revised (PCL-R) are used to support decisions regarding personal liberty. In our study, performed in an applied forensic psychiatric setting, intraclass correlation coefficients (ICC) for absolute agreement, single rater (ICCA1) were .89 for the total score, .82 for Factor 1, .88 for Factor 2, and .78 to .86 for the four facets. These results stand in contrast to lower reliabilities found in a majority of field studies. Disagreement among raters made a low contribution (0%-5%) to variability of scores on the total score, factor, and facet level. For individual items, ICCA1 varied from .38 to .94, with >.80 for seven of the 20 items. Items 17 (“Many short-term marital relationships”) and 19 (“Revocation of conditional release”) showed very low reliabilities (.38 and .43, respectively). The importance of knowledge about factors that can affect scoring of forensic instruments (e.g., education, training, experience, motivation, raters’ personality, and quality of file data) is emphasized.

  • 5.
    Dåderman, Anna M.
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Wennberg, Peter
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Törestad, Bertil
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Using the Karolinska Scales of Personality on male juvenile delinquents: relationships between scales and factor structure.2005Ingår i: Nordic Journal of Psychiatry, ISSN 0803-9488, Vol. 59, nr 6, s. 448-456Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of the present study was to investigate relationships between scales from the Karolinska Scales of Personality (KSP) and the factor structure of the KSP in a sample of male juvenile delinquents. The KSP was administered to a group of male juvenile delinquents (n = 55, mean age 17 years; standard deviation = 1.2) from four Swedish national correctional institutions for serious offenders. As expected, the KSP showed appropriate correlations between the scales. Factor analysis (maximum likelihood) arrived at a four-factor solution in this sample, which is in line with previous research performed in a non-clinical sample of Swedish males. More research is needed in a somewhat larger sample of juvenile delinquents in order to confirm the present results regarding the factor solution.

  • 6. Dåderman, Anna Maria
    et al.
    Kajonius, Petri Juhani
    Hallberg, Angela
    Skog, Sandra
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen, Perception och psykofysik.
    Leading with a cool head and a warm heart: trait-based leadership resources linked to task performance, perceived stress, and work engagement2023Ingår i: Current Psychology, ISSN 1046-1310, E-ISSN 1936-4733, Vol. 42, s. 29559-29580Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Leaders of today need to achieve well in terms of task performance, perceiving low stress, and having high levels of work engagement. One may ask whether trait-based leadership resource factors can be identified and how such resource factors might relate to task performance, perceived stress, and work engagement. Our aim was to test the hypothesis, derived from Hobfoll’s motivational Conservation of Resources (COR) theory, that there are trait-based leadership resource factors, which are differentially correlated to the leaders’ task performance, perceived stress, and work engagement. Leaders (N = 344) aged from 23 to 65 years (M = 49, SD = 8.6; 58% women) completed an online questionnaire including measures of task performance, perceived stress, work engagement, personality traits, trait emotional intelligence, empathy, performance-related self-esteem, compassionate and rational leadership competence, and coping resources for stress. Using exploratory factor analysis, we identified four trait-based leadership resource factors. With Bonferroni adjustment, and controlling for sex, age, number of years in the current managerial position, self-deceptive enhancement, and impression management, only Rational Mastery was significantly positively correlated with task performance. Rational Mastery, Efficient Coping, and Modesty were negatively correlated with perceived stress, and all factors except Modesty, but including the fourth (Good-Heartedness) were positively correlated with work engagement. Organizations striving for sustainable work conditions should support trait-based leadership, which depends not only on a task-oriented resource such as rational mastery, but also on human-oriented resources such as efficient coping, modesty, and good-heartedness, all of them being differentially related to task performance, perceived stress, and work engagement.

  • 7.
    Eisler, Hannes
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen. Perception & Psykofysik.
    Eisler, Anna D.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Psychophysical issues in the study of time perception.2008Ingår i: Psychology of time, Emerald, Bingley, UK , 2008, s. 75-109Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    This chapter on psychophysical issues in the study of time perception is organized around two main research topics: one topic is related to questions concerning the comparison of successive time intervals; and the other topic is related to the psychophysical function for duration.

  • 8. Englund, Mats P.
    et al.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Beware how you compare: comparison direction dictates stimulus-valence-modulated presentation-order effects in preference judgment2013Ingår i: Attention, Perception & Psychophysics, ISSN 1943-3921, E-ISSN 1943-393X, Vol. 75, nr 5, s. 1001-1011Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Englund and Hellstrom (Journal of Behavioral Decision Making 25: 82-94, 2012a) found a tendency to prefer the left (first-read) of two attractive alternatives but the right (second-read) of two unattractive alternatives-a valence-dependent word-order effect (WOE). They used stimulus pairs spaced horizontally, and preference was indicated by choosing one of several written statements (e. g., apple I like more than pear). The results were interpreted as being due to stimulus position, with the magnitude of the left stimulus having a greater impact on the comparison outcome than the magnitude of the right. Here we investigated the effects of the positioning of the stimuli versus the semantics of the response alternatives (i.e., comparison direction) on the relative impacts of the stimuli. Participants rated preferences for stimuli spaced horizontally with the response alternatives not dictating a comparison direction (Exp. 1), and stimuli spaced vertically using Englund and Hellstrom's (Journal of Behavioral Decision Making 25: 82-94, 2012a) response alternatives, which dictate a comparison direction semantically (Exp. 2). The results showed that the valence-dependent WOE found by Englund and Hellstrom (Journal of Behavioral Decision Making 25: 82-94, 2012a) was not due to the horizontal stimulus positioning per se, but to the induced comparison direction, with the effect probably being mediated by attention directed at the subject of the comparison. We concluded that a set comparison direction is required for the valence-dependent WOE to appear, and that using Hellstrom's sensation-weighting model to determine stimulus weights is a way to verify the comparison direction.

  • 9.
    Englund, Mats P.
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    If you have a choice, you have trouble: Stimulus valence modulates presentation-order effects in preference judgment2012Ingår i: Journal of Behavioral Decision Making, ISSN 0894-3257, E-ISSN 1099-0771, Vol. 25, nr 1, s. 82-94Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is well known that the presentation order of choice options often affects decision outcomes to a significant degree. However, despite the significance and wide occurrence of the effects, they are ignored in most preference models. Furthermore, psychophysical findings of stimulus-magnitude dependent presentation-order effects have not been acknowledged previously in the cognitive literature on preference judgments. Thus, the potential moderating effect of the level of stimulus magnitude (here, valence) on the direction and size of order effects in preference judgment has not been investigated previously. In two experiments, participants (117 and 204, respectively) rated their preference for pairs of everyday-type objects and phenomena (e.g., apple–pear, headache–stomachache). Stimuli were spaced horizontally, and each participant received them in one of two opposite within-pair presentation orders. Participants also rated the stimuli's valence on a scale from very bad to very good. The results showed a positive correlation between the rated valence and the tendency to prefer the first-mentioned (left) stimulus; that is, the effect was greatest, and opposite, for choices between the most attractive and the most unattractive options, respectively. In terms of Hellström's (1979) sensation-weighting model, the positive correlation is caused by a higher weight (i.e., impact on the preference judgment) for the left stimulus than for the right, which is possibly due to the left stimulus being compared to the right. The results suggest that researchers may have failed previously to find important moderators of presentation-order effects in preference judgment due to the failure to use sufficiently attractive or unattractive stimuli.

  • 10.
    Englund, Mats P.
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Presentation-order effects for aesthetic stimulus preference2012Ingår i: Attention, Perception & Psychophysics, ISSN 1943-3921, E-ISSN 1943-393X, Vol. 74, nr 7, s. 1499-1511Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For preference comparisons of paired successive musical excerpts, Koh (American Journal of Psychology, 80, 171-185, 1967) found time-order effects (TOEs) that correlated negatively with stimulus valence-the first (vs. the second) of two unpleasant (vs. two pleasant) excerpts tended to be preferred. We present three experiments designed to investigate whether valence-level-dependent order effects for aesthetic preference (a) can be accounted for using Hellstrom's (e.g., Journal of Experimental Psychology: Human Perception and Performance, 5, 460-477, 1979) sensation-weighting (SW) model, (b) can be generalized to successive and to simultaneous visual stimuli, and (c) vary, in accordance with the stimulus weighting, with interstimulus interval (ISI; for successive stimuli) or stimulus duration (for simultaneous stimuli). Participants compared paired successive jingles (Exp. 1), successive color patterns (Exp. 2), and simultaneous color patterns (Exp. 3), selecting the preferred stimulus. The results were well described by the SW model, which provided a better fit than did two extended versions of the Bradley-Terry-Luce model. Experiments 1 and 2 revealed higher weights for the second stimulus than for the first, and negatively valence-level-dependent TOEs. In Experiment 3, there was no laterality effect on the stimulus weighting and no valence-level-dependent space-order effects (SOEs). In terms of the SW model, the valence-level-dependent TOEs can be explained as a consequence of differential stimulus weighting in combination with stimulus valence varying from low to high, and the absence of valence-level-dependent SOEs as a consequence of the absence of differential weighting. For successive stimuli, there were no important effects of ISI on weightings and TOEs, and, for simultaneous stimuli, duration had only a small effect on the weighting.

  • 11.
    Englund, Mats P.
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Presentation-Order Effects for Aesthetic Stimulus PreferenceManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    For preference comparisons of paired successive musical excerpts, Koh (1967) found time-order effects (TOEs) that correlated negatively with stimulus valence–a tendency to prefer the first of two unpleasant excerpts and vice versa. Here we present three experiments designed to investigate whether valence-level dependent order effects for aesthetic preference (a) can be accounted for using Hellström’s (e.g., 1979) sensation-weighting (SW) model, (b) can be generalized to successive and to simultaneous visual stimuli, and (c) vary, in accordance with the stimulus weighting, with interstimulus interval (ISI; successive stimuli) or stimulus duration (simultaneous stimuli). Participants compared paired successive jingles (Experiment 1), successive color patterns (Experiment 2), and simultaneous color patterns (Experiment 3), selecting the preferred stimulus in each pair. Results were described well with the SW model: In Experiments 1 and 2, there were consistently higher weights for the second stimulus than for the first and negatively valence-level dependent TOEs. In Experiment 3, there was no consistent laterality effect on the stimulus weighting and no valence-level dependent SOE. In terms of the SW model, the valence-level dependent TOEs can be explained as a consequence of the differential stimulus weighting in combination with stimulus valence varying from low to high, and the absence of valence-level dependent SOEs as a consequence of the absence of systematic differential stimulus weighting. For successive stimuli, there were no important effects of ISI on the stimulus weighting and TOEs, and, for simultaneous stimuli, there was only a small effect of duration on the stimulus weighting, possibly reflecting stimulus scanning.

  • 12. Fernaeus, Sven-Erik
    et al.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen, Perception och psykofysik.
    Conceptual elaboration versus direct lexical access in WAIS-similarities: differential effects of white-matter lesions and gray matter volumes2018Ingår i: Aging, Neuropsychology and Cognition, ISSN 1382-5585, E-ISSN 1744-4128, Vol. 25, nr 6, s. 893-903Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Wechsler Adult Intelligence Scale (WAIS) subscale Similarities have been classified as a test of either verbal comprehension or of inductive reasoning. The reason may be that items divide into two categories. We tested the hypothesis of heterogeneity of items in WAIS-Similarities. Consecutive patients at a memory clinic and healthy controls participated in the study. White-matter hyperintensities (WMHs) and normalized temporal lobe volumes were measured based on Magnetic resonance Imaging (MRI), and tests of verbal memory and attention were used in addition to WAIS-Similarities to collect behavioural data. Factor analysis supported the hypothesis that two factors are involved in the performance of WAIS-similarities: (1) semiautomatic lexical access and (2) conceptual elaboration. These factors were highly correlated but provided discriminative diagnostic information: In logistic regression analyses, scores of the lexical access factor and of the conceptual elaboration factor discriminated patients with mild cognitive impairment from Alzheimer’s disease patients and from healthy controls, respectively. High scores of WMH, indicating periventricular white-matter lesions, predicted factor scores of direct lexical access but not those of conceptual elaboration, which were predicted only by medial and lateral temporal lobe volumes.

  • 13. Fernaeus, Sven-Erik
    et al.
    Östberg, Per
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Wahlund, Lars-Olof
    Cut the coda: Early fluency intervals predict diagnoses2008Ingår i: Cortex, ISSN 0010-9452, E-ISSN 1973-8102, Vol. 44, nr 2, s. 161-169Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study was threefold: (i) to clarify whether letter and category fluency tap different cognitive abilities; (ii) to make diagnostic comparisons and predictions using temporally resolved fluency data; (iii) to challenge and test the widely made assumption that 1-min sum scores are the fluency test measure of choice in the diagnosis of dementia. Scores from six 10-sec intervals of letter and category fluency tests were obtained from 240 participants including cognitive levels ranging from mild subjective cognitive complaints to Alzheimer's disease. Factor analysis revealed clearly separate factors corresponding to letter and category fluency. Category fluency was markedly impaired in Alzheimer's disease but not in Mild Cognitive Impairment. Only scores from relatively early intervals predicted Alzheimer's disease and Mild Cognitive Impairment. The conclusions are (i) letter and category fluency are different tests, category fluency being the best diagnostic predictor; (ii) it would be possible to administer category fluency tests only for 30 sec, because after this point the necessary differential diagnostic information about the patient's word fluency capacity has already been gathered.

  • 14.
    Fernaeus, Sven-Erik
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen. Karolinska Institutet, Sweden .
    Östberg, Per
    Wahlund, Lars-Olof
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Memory factors in Rey AVLT: implications for early staging of cognitive decline2014Ingår i: Scandinavian Journal of Psychology, ISSN 0036-5564, E-ISSN 1467-9450, Vol. 55, nr 6, s. 546-553Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Supraspan verbal list learning is widely used to assess dementia and related cognitive disorders where declarative memory deficits are a major clinical sign. While the overall learning rate is important for diagnosis, serial position patterns may give insight into more specific memory processes in patients with cognitive impairment. This study explored these patterns in a memory clinic clientele. One hundred eighty three participants took the Rey Auditory-Verbal Learning Test (RAVLT). The major groups were patients with Alzheimer's disease (AD), Vascular Dementia (VD), Mild Cognitive Impairment (MCI), and Subjective Cognitive Impairment (SCI) as well as healthy controls (HC). Raw scores for the five trials and five serial partitions were factor analysed. Three memory factors were found and interpreted as Primacy, Recency, and Resistance to Interference. AD and MCI patients had impaired scores in all factors. SCI patients were significantly impaired in the Resistance to Interference factor, and in the Recency factor at the first trial. The main conclusion is that serial position data from word list testing reflect specific memory capacities which vary with levels of cognitive impairment.

  • 15.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Anatomy of stimulus comparison.2005Ingår i: Fechner Day 2005: Proceedings of the 21st Annual Meeting of the International Society for Psychophysics, 2005, s. 113-118Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Stimulus comparison by human observers is a more complex process than the subtraction carried out by a simple comparator. This is shown by the patterns of time- and space-order "errors." Specifically, experiments show that the two compared stimuli exert differential influence on the comparative response. This invalidates models based on additive bias or semantic congruity. The sensation-weighting (SW) model can account for many of the results. One important consequence is that the discriminability of two stimuli depends on which of them is varied.

  • 16.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen, Perception och psykofysik.
    Explaining the anomalous results of stimulus comparison: Noisy target correlates help optimize discrimination2022Ingår i: Fechner Day 2022: Proceedings of the 38th Annual Meeting of the International Society for Psychophysics / [ed] G. R. Patching, Lund: International Society for Psychophysics , 2022, s. 37-40Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The basic idea of weighting in stimulus comparison has become widely accepted. However, Hellström's (1979) sensation-weighting model (SWM) for stimulus comparison is still controversial. The full range of results of the experiment that the SWM was originally based on has remained neglected. Some of these results are "anomalous" and must be seen as a serious challenge for modelers who seek to apply currently popular ideas, such as Bayesian optimization, to stimulus comparison. Here, based on the SWM, the weighing-in of reference levels for discrimination optimization is discussed, emphasizing the potential role of noisy target correlates (NTCs).

  • 17.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    In memoriam: Hannes Eisler, 1923-20152015Ingår i: Fechner Day 2015 : Proceedings of the 31st Annual Meeting of The International Society for Psychophysics / [ed] Simon Grondin, Vincent Laflamme, Québec, Canada: International Society for Psychophysics , 2015, s. xi-xiiKonferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Our very distinguished member, Professor Hannes Eisler, Stockholm University, has left us. He died on May 28, 2015, at the age of 91. He was a member of the ISP from its beginnings. At Fechner Day 2014 in Lund, Sweden, Hannes lectured on "Some research tips from 55 years' psychophysics." Informally, he named this presentation his "swan song."

    Hannes was born in Vienna, Austria, 1923, and at the age of 15 fled to Sweden to escape the Nazis. Initially Hannes worked as a farm hand but quickly progressed to study at high school and later at Stockholm University, where he became an adept of Gösta Ekman, the Swedish pioneer of quantitative psychology. After spending a year in S. S. Stevens’ lab at Harvard, Hannes was awarded his Ph.D. in Stockholm 1963. In 1994, as the result of a petition from all Swedish psychology professors, the Swedish government awarded Hannes Eisler the rank and honor of Professor – a rare recognition of scientific merit.

    During his long career, Hannes authored a large number of publications and made many important contributions to our field. His doctoral dissertation was about the relation between magnitude and category scales. Later on, he turned much of his interest toward time perception in people as well as in mice. Perhaps the most impressive of his contributions is the Parallel Clock model for temporal reproduction and comparison1, which arose from Hannes’ arduous and meticulous investigation of long known anomalies in time perception; specifically, breaks in psychophysical functions. Noting the positions of those breaks in reproduction data led him to the counter-intuitive realization that participants use a seemingly odd strategy in immediate reproduction of temporal intervals: subjectively matching the reproduction, not to the standard, but to one-half of the total duration. Using this model it is possible to estimate the psycho-physical function for time from reproduction data, and Hannes published a huge collection of temporal power function exponents2 – much cited but all too often with no understanding of how they were determined.

    Hannes was intellectually perspicacious and possessed research talent in abundance. Modesty, good nature, along with deep and diverse cultural interests, sense of humor, and appreciation of the good things in life, were some of his other characteristics. Scientific seminars on various topics were enriched by his insightful comments until a heart attack sadly ended his long life.

    I miss Hannes immensely, as a very good old friend, a respected senior colleague, and a mentor – even the word guru feels very appropriate.

  • 18.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Integration of stimulus dimensions in judgments of area and shape: Modeling guided by level curves2015Ingår i: Fechner Day 2015: Proceedings of the 31st Annual Meeting of The International Society for Psychophysics / [ed] Simon Grondin, Vincent Laflamme, Québec, Canada: International Society for Psychophysics , 2015, s. 17-17Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    In the horizontal-vertical (H-V) illusion (Künnapas, 1958) the judged V/H ratio is larger than the physical ratio. This tendency is not found in V/H ratio judgments of rectangles (Gärling & Dalkvist, 1977), but these judgments are not based on the simple ratio of V and H: Level-curves (iso-judgment contours) of logarithmized data show that the larger dimension is more important than the smaller. Developmentally, judgments of rectangular area have been described as changing from adding V and H in children to multiplying  them in adults (Wilkening, 1979). However, level curves demonstrate deviations from simple models at all ages. Adults’ area judgments show a greater importance of the larger dimension, and also a greater importance of H than of V, but accurate modeling is difficult. Here, level-curve plots (using R’s contour function) prove invaluable for graphic guidance of modeling by displaying systematic judgment tendencies that go unnoticed with conventional factorial plots.

  • 19.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen, Perception och psykofysik.
    Något om psykofysiken och dess utvecklingi Stockholm... ur mitt perspektiv2020Ingår i: Historien om svensk psykologisk forskning: Utvecklingen från perception och psykofysik / [ed] Gunn Johansson, Stockholm: Kungl. Vitterhets Historie och Antikvitets Akademien, 2020, s. 97-106Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 20.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Temporal asymmetry and “magnet effect” in similarity and discrimination of prototypical and nonprototypical stimuli: Consequences of differential sensation weighting2007Ingår i: Fechner Day 2007: Proceedings of the 23rd Annual Meeting of the International Society for Psychophysics, 2007, s. 283-288Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The judged similarity between two successive stimuli is higher when the less prototypical stimulus is the first in the pair than when it is the last. Also, the rated similarity between a scalar and a nonscalar melody is greater when the nonscalar melody comes first rather than last in the pair, and a change from a mistuned to a tuned musical interval is harder to detect than when the order is reversed. Such time-order asymmetries can be accounted for by a generalization of Hellström’s sensation-weighting model, with a lower weight for the first stimulus as is usual when two successive stimuli are compared. This would result in assimi-lation of a first-presented nonprototypical stimulus toward the prototype, increasing its similarity to a more prototypical last-presented stimulus. Also, fewer “different” judgments, but not worse discrimination from variants, occur for prototypical than for nonprototypical stimuli; the so-called perceptual magnet effect appears to be a methodology-based artifact.

  • 21.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Time- and space-order effects in stimulus comparison in the light of response-time data2008Ingår i: Fechner Day 2008: Proceedings of the 24th Annual Meeting of the International Society for Psychophysics, 2008, s. 139-144Konferensbidrag (Refereegranskat)
    Abstract [en]

    As has been found experimentally, magnitude comparison of paired successive or simultaneous stimuli can be described as being based on differential subtractive weighting of the stimulus-induced sensations ψ1 and ψ2, causing time- and space-order effects (TOEs and

    SOEs). In the simplest case, the comparison equation becomes: d = s1 (ψ1 - ψr) - s2 (ψ2 - ψr), where ψr is the reference level (ReL). New analyses of response-time data from stimulus comparison experiments (Hellström, 2003) show that signed response speed, the inverse of response time with the sign of the subjective difference d, carries similar information on d as measures based on transformed proportions of "1st greater," "equal," and "2nd greater" responses. Sensation weighting is similar for fast and slow responses, which suggests that it arises in a preceding processing stage, and strengthens the notion that the weighting, and thereby TOEs and SOEs, is of perceptual origin.

  • 22.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Time-order effects and generalized subjective magnitude in crossmodal stimulus comparison2014Ingår i: Proceedings of the 30th Annual Meeting of the International Society for Psychophysics / [ed] G. R. Patching, M. Johnson, E. Borg, Å. Hellström, Lund, Sweden: International Society for Psychophysics , 2014, s. 33-33Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Crossmodal comparability for stimulus magnitudes on modalities lacking a common intensity aspect, such as line length and tone loudness, may rest on a more general magnitude concept.

    In a recent study1, possible time-order error (TOE)-like effects were looked for in crossmodal comparison of successive stimuli. Hellstro ̈m’s2 sensation-weighting (SW) model was adapted for use as a descriptive and analytical tool. According to this model, the real comparison takes place between two weighted subjective compounds, each built up by the sensation magnitudes of a stimulus (weight s1 or s2) and of its reference level (ReL) (weight 1 − s1 or 1 − s2).

    Intramodally (tone-tone, line-line) and crossmodally (tone-line, line-tone) paired stimuli, with duration 150 ms and ISIs 400 and 2000 ms, were compared for their strength, with the alternatives 1st stronger, 2nd stronger, and equal, yielding scaled subjective difference (D) of +100, 0, and -100. The extended SW model, for a pair with a tone followed by a line, is

    D=kT[s1(Φ1T −Φ0T)+(1−s1)(Φr1T −Φ0T)]−kL[s2(Φ2L −Φ0L)+(1−s2)(Φr2L −Φ0L)]+b 1a = s1kT (Φ1T −Φr1T )−s2kL(Φ2L −Φr2L)+kT (Φr1T −Φ0T )−kL(Φr2L −Φ0L)+b, 1b

    where Φ is the physical stimulus magnitude on a scale, -4 through +4 for lines as well as tones (90–170 mm, and 74.7–81.1 dB). It was assumed that, within these ranges, Φ = k(Φ − Φ0), where Ψ is the subjective magnitude and Φ0 is the Φ value for Ψ = 0. k is a modality-specific scale factor. Subscripts T and L indicate tone and line; 1 and 2 indicate temporal position. Φr is the physical magnitude of the ReL. b is possible bias. The experimental design, varying both stimulus magnitudes, allowed estimation of the relevant model parameters from the data.

    Comparing a tone and a line for their “strength” was indeed feasible, yielding weighting effects and TOEs (assessed by mean D) resembling those in intramodal comparison. In terms of the SW model, with ISI = 2000 ms s1 < s2. TOEs were generally more negative with the 2000–ms than with the 200–ms ISI. The results were well accounted for by the SW model.

    Eq. 1b implies that the effective subjective magnitude of each paired stimulus is its ReL plus its deviation from the ReL multiplied by s. Estimates of kT and kL were similar, indi- cating crossmodally similar ranges of Ψ. Based on this and on findings3, 4 that context effects are much stronger crossmodally than intramodally, it may be hypothesized that in crossmodal comparison the k value for each modality becomes inversely related to the range or spread of the sensation magnitudes in the modality. In the SW model (Eq. 1b) this would mean that the stimulus-dependent parts of the compared magnitudes are standardized quantities, like z values. These would be dimensionless, removing the need for an intermodal “currency exchange” and accounting for comparability of subjective magnitudes in very different modalities.

  • 23.
    Hellström, Åke
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Cederström, Caroline
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Cross-modality in comparisons of successive stimuli2012Ingår i: Fechner Day 2012: Proceedings of the 28th Annual Meeting of the International Society for Psychophysics, Ottawa, Ontario, Canada, October 18-21, 2012 / [ed] C. Leth-Steensen, J. R. Schoenherr, Ottawa, Kanada: The International Society for Psychophysics , 2012, s. 168-173Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Two experiments were performed to study effects of modality, temporal position, and their in- teraction on comparisons of successive stimuli. In Experiment 1, intramodal (tone-tone and line-line) and crossmodal (tone-line and line-tone) stimulus pairs, with two interstimulus in- tervals (ISIs), were presented. Participants indicated which stimulus was the “stronger.” Time-order effects (TOEs) were studied using the classic D% measure as well as weighting coefficients from Hellström’s sensation weighting model. TOEs were found in both intramo- dal and crossmodal comparisons. The classic pause-function (more negative TOE with longer ISIs) was found in all pair types except tone-line. In Experiment 2, participants indicated which of two lines was the longer, or which of two tones was the louder. Intramodal anchors, crossmodal anchors, or no anchors were interpolated between the stimuli. Anchoring tended to yield negative TOEs and to diminish the first stimulus’ weight. Intramodal anchoring of tone-tone pairs yielded low stimulus weights, suggesting stimulus interference.

  • 24.
    Hellström, Åke
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Cederström, Caroline
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Intramodal and crossmodal pairing and anchoring in comparisons of successive stimuli2014Ingår i: Attention, Perception & Psychophysics, ISSN 1943-3921, E-ISSN 1943-393X, Vol. 76, nr 4, s. 1197-1211Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two experiments were conducted to study effects of modality, temporal position, and their interaction on comparisons of successive stimuli. In Experiment 1, intramodal (tone-tone and line-line) and crossmodal (tone-line and line-tone) stimulus pairs, with two interstimulus intervals (ISIs), 400 and 2,000 ms, were presented. Participants indicated which stimulus was the stronger. Time-order errors (TOEs) were assessed using the D% measure and were found in all types of pairs. Variation in TOEs across conditions was well accounted for by changes in parameters (stimulus weights, reference levels) in an extended version of Hellstrom's sensation weighting (SW) model. With an ISI of 2,000 ms, the first stimulus had a lower weight (less impact on the response) than did the second stimulus. More negative TOEs were found with the longer ISI in all pair types except tone-line. In Experiment 2, participants indicated which of two lines was the longer or which of two tones was the louder. An intra-or crossmodal anchor, or no anchor, was interpolated between the stimuli. Anchoring tended to reduce the weight of the first stimulus, suggesting interference with memory, and to yield negative TOEs. Intramodal anchors yielded reduced weights of both stimuli, most dramatically for tones, suggesting an additional effect of stimulus interference. Response times decreased with crossmodal anchors. For line-line pairs, strong negative TOEs were found. In both experiments, the variation in TOE across conditions was well accounted for by the SW model.

  • 25.
    Hellström, Åke
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Patching, Geoffrey P.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Assessment and interpretation of bias in 2AFC stimulus comparison through chronometric analysis2011Ingår i: Fechner Day 2011: Proceedings of the Twenty-Seventh Annual Meeting of the International Society for Psychophysics / [ed] D. Algom, D. Zakay, E. Chajut, S. Shaki, Y. Mama, & V. Shakuf, Raanana, Israel: International Society for Psychophysics , 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Random-walk and diffusion models for two-choice comparison of paired successive or simultaneous stimuli focus on response time (RT), modeled as the time needed to reach one or the other barrier, and its relation to the response probabilities. Logit P1 = ln[P1/(1-P1)], where P1 is the probability of responding ”first greater,” can be seen as a measure of subjective stimulus difference, d. Signed response speed (SRS), ±1/RT with the sign of the response, yields another d measure. The two measures are highly correlated and, importantly, the intercept in the regression of logit P1 on mean SRS estimates the asymmetry of the starting point relative to the barriers, that is, the bias. New analyses of data from Patching, Englund, and Hellström (2011) show that this bias helps explain the variability of the time-and space order errors. Possible connections of the bias with the parameters in Hellström’s (2003) sensation-weighting (SW) model are explored.

  • 26.
    Hellström, Åke
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen, Perception och psykofysik.
    Patching, Geoffrey R.
    Rammsayer, Thomas H.
    Sensation weighting in duration discrimination: A univariate, multivariate, and varied-design study of presentation-order effects2020Ingår i: Attention, Perception & Psychophysics, ISSN 1943-3921, E-ISSN 1943-393X, Vol. 82, s. 3196-3220Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Stimulus discriminability is often assessed by comparisons of two successive stimuli: a fixed standard (St) and a varied comparison stimulus (Co). Hellstrom's sensation weighting (SW) model describes the subjective difference between St and Co as a difference between two weighted compounds, each comprising a stimulus and its internal reference level (ReL). The presentation order of St and Co has two important effects: Relative overestimation of one stimulus is caused by perceptual time-order errors (TOEs), as well as by judgment biases. Also, sensitivity to changes in Co tends to differ between orders StCo and CoSt: the Type B effect. In three duration discrimination experiments, difference limens (DLs) were estimated by an adaptive staircase method. The SW model was adapted for modeling of DLs generated with this method. In Experiments 1 and 2, St durations were 100, 215, 464, and 1,000 ms in separate blocks. TOEs and Type B effects were assessed with univariate and multivariate analyses, and were well accounted for by the SW model, suggesting that the two effects are closely related, as this model predicts. With short St durations, lower DLs were found with the order CoSt than with StCo, challenging alternative models. In Experiment 3, St durations of 100 and 215 ms, or 464 and 1,000 ms, were intermixed within a block. From the SW model this was predicted to shift the ReL for the first-presented interval, thereby also shifting the TOE. This prediction was confirmed, strengthening the SW model's account of the comparison of stimulus magnitudes.

  • 27.
    Hellström, Åke
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen, Perception och psykofysik.
    Rammsayer, Thomas
    Effects of sensitivity, bias, and stimulus presentation order in comparative discrimination of interval durations: A univariate and multivariate study2018Ingår i: Fechner Day 2018: Proceedings of the 34th Annual Meeting of the International Society for Psychophysics / [ed] Friedrich Müller, Lara Ludwigs, Malizia Kupper, International Society for Psychophysics , 2018, s. 266-271Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    According to the sensation weighting model (SWM), stimulus magnitude level dependent time-order errors (TOEs) in stimulus comparison arise from uneven stimulus weighting, levered by asymmetry of an internal reference level; the weighting also causes discriminability to depend on the presentation order of standard (St) and comparison stimulus (Co) (the Type B effect). Both of these effects, as well as judgment bias, determine the measured difference limen (DL). In two duration discrimination experiments, these contributions to the DL were explored, using an adaptive staircase method. The compared intervals were filled auditory or empty visual. The interstimulus interval was 900 ms and the St duration 100, 215, 464, or 1000 ms in a blocked design. In univariate as well as multivariate analyses, the SWM’s predictions were confirmed on the individual level, and the contributions of sensitivity, bias, and weighting in building the DL were assessed.

  • 28.
    Hellström, Åke
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Rammsayer, Thomas H.
    Time-order errors and standard-position effects in duration discrimination: An experimental study and an analysis by the sensation-weighting model2015Ingår i: Attention, Perception & Psychophysics, ISSN 1943-3921, E-ISSN 1943-393X, Vol. 77, nr 7, s. 2409-2423Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Studies have shown that the discriminability of successive time intervals depends on the presentation order of the standard (St) and the comparison (Co) stimuli. Also, this order affects the point of subjective equality. The first effect is here called the standard-position effect (SPE); the latter is known as the time-order error. In the present study, we investigated how these two effects vary across interval types and standard durations, using Hellstrom's sensation-weighting model to describe the results and relate them to stimulus comparison mechanisms. In Experiment 1, four modes of interval presentation were used, factorially combining interval type (filled, empty) and sensory modality (auditory, visual). For each mode, two presentation orders (St-Co, Co-St) and two standard durations (100 ms, 1,000 ms) were used; half of the participants received correctness feedback, and half of them did not. The interstimulus interval was 900 ms. The SPEs were negative (i.e., a smaller difference limen for St-Co than for Co-St), except for the filled-auditory and empty-visual 100-ms standards, for which a positive effect was obtained. In Experiment 2, duration discrimination was investigated for filled auditory intervals with four standards between 100 and 1,000 ms, an interstimulus interval of 900 ms, and no feedback. Standard duration interacted with presentation order, here yielding SPEs that were negative for standards of 100 and 1,000 ms, but positive for 215 and 464 ms. Our findings indicate that the SPE can be positive as well as negative, depending on the interval type and standard duration, reflecting the relative weighting of the stimulus information, as is described by the sensation-weighting model.

  • 29.
    Hellström, Åke
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Rammsayer, Thomas H.
    Weber fractions and time-order errors for long and short durations: implications for modeling2013Ingår i: Fechner Day 2013: Proceedings of the 29th Annual Meeting of The International Society for Psychophysics / [ed] Jiri Wackermann, Marc Wittmann, Wolfgang Skrandies, Freiburg, Germany: International Society for Psychophysics , 2013, s. 28-28Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Using a weighted up-down procedure, in each of eight conditions 28 participants compared durations of auditory (noise bursts) or visual (LED flashes) intervals; filled or unfilled with 3-ms markers; with or without feedback. Standards (Sts) were 100 and 1000 ms, and the ISI 900 ms. Intermixedly, presentation orders were St-Comparison (Co) and Co-St. TOEs were positive for St=100-ms and negative for St=1000 ms. Weber fractions (WFs, JND/St) were lowered by feedback. For visual-filled and visual-empty, WFs were highest for St=100 ms. For auditory-filled and visual-empty, St interacted with Order: lowest WFs occurred for St-Co with St=1000 ms, but for Co-St with St=100 ms. Lowest average WFs occurred with St-Co for visual-filled, but with Co-St for visual-empty. The results refute the generalization of better discrimination with St-Co than with Co-St (”type-B effect”), and support the notion of sensation weighting: flexibly differential impact weights of the compared durations in generating the response.

  • 30.
    Laurell, Jenny
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Belfrage, Henrik
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Deceptive behaviour and instrumental violence among psychopathic and non-psychopathic violent forensic psychiatric patients2014Ingår i: Psychology, Crime and Law, ISSN 1068-316X, E-ISSN 1477-2744, Vol. 20, nr 5, s. 467-479Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Deceptive behaviour and instrumental violence are well-known psychopathic features and as such play important roles in the assessment of psychopathy. This study examined first, the nature of the violence committed by offenders that have been admitted to forensic psychiatric care and whether scores on the Psychopathy Checklist: Screening Version (PCL:SV), Part 1, were associated with the instrumentality of violence. Second, we examined the proneness of offenders to re-frame the instrumentality in their past violent crimes, and whether this was associated with scores on the PCL:SV. The results show that the PCL:SV, Part 1 (interpersonal/affective features), was positively related to the officially coded instrumentality of the violent crimes. As expected, this association disappeared when the instrumentality was self-reported. However, the majority of the patients tended to exaggerate the reactivity of their violent crimes when it was self-reported, indicating that most offenders, independently of level of psychopathy, used deception when questioned about the characteristics of their past violent crimes. The reasons for, and implications of, the use of deception are discussed.

  • 31.
    Laurell, Jenny
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Belfrage, Henrik
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Facets on the psychopathy checklist screening version and instrumental violence in forensic psychiatric patients2010Ingår i: CBMH. Criminal behaviour and mental health, ISSN 0957-9664, E-ISSN 1471-2857, Vol. 20, nr 4, s. 285-294Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background There is a recognised relationship between psychopathy and instrumental violence, but not all violence by people who meet the criteria for psychopathy is instrumental. Aims Our aims were to compare offence types among forensic psychiatric patients with and without the Psychopathy Checklist: Screening Version (PCL: SV) criteria for psychopathy. Our specific questions were whether factor 1 the interpersonal affective dimension was related to instrumentality and on severity of the violent crime. Our hypothesis was that the relationship between psychopathy and instrumental violence would be dependent on the severity of the violent crime. Methods Sixty-five male patients at the forensic psychiatric hospital in Sundsvall, all with a violent criminal history, were assessed for psychopathy through interview and records using the PCL: SV. Severity and the instrumentality of their previous violence were coded using the Cornell coding guide for violent incidents. Results The interpersonal features of psychopathy (the interpersonal facet), and only the interpersonal features were significantly associated with instrumentality and severity of violence. Instrumentality was also significantly related to the severity of the violence, independent of psychopathy score. Conclusions The results indicated that, at least among forensic psychiatric patients, planning is more likely than not with respect to serious crimes. The specific link between interpersonal features of psychopathy and instrumental and severe violence suggests potential clinical value in recognising subtypes of psychopathy.

  • 32.
    Lindqvist, Judit
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Dåderman, A.M.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Internal reliability and construct validity of the Novaco Anger Scale-1998-S in a sample of violent prison inmates in Sweden2005Ingår i: Psychology, Crime and Law, ISSN 1068-316X, E-ISSN 1477-2744, Vol. 11, nr 2, s. 223-237Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, the internal reliability and construct validity of the recently adapted Swedish version of the Novaco Anger Scale (NAS-1998-S; Lindqvist, Dderman, & Hellstrm, Social Behavior and Personality, 8, 773-788, 2003), as well as its scale correlations with demographic and criminality variables, were investigated. Construct validity was established by assessing the correlation pattern of the scales of NAS-1998-S with concurrent scales of similar and distinct constructs. Ninety-five male violent prisoners, ranging in age from 18 to 67 years, participated. The results demonstrated good internal reliability, consistent intrascale relationships, and appropriate construct validity of NAS-1998-S. The number of previous convictions had a moderate negative relationship with the capacity of control. Age and education correlated negatively with the NAS-1998-S scales, except Regulation. In addition to psychometric issues, the results were discussed from a clinical perspective on the offender population.

  • 33.
    Patching, Geoffrey R.
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Englund, Mats P.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Time- and space-order effects in timed discrimination of brightness and size of paired visual stimuli2012Ingår i: Journal of Experimental Psychology: Human Perception and Performance, ISSN 0096-1523, E-ISSN 1939-1277, Vol. 38, nr 4, s. 915-940Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Despite the importance of both response probability and response time for testing models of choice there is a dearth of chronometric studies examining systematic asymmetries that occur over time- and space-orders in the method of paired comparisons. In this study, systematic asymmetries in discriminating the magnitude of paired visual stimuli are examined by way of log-odds ratios of binary responses as well as by signed response speed. Hierarchical Bayesian modeling is used to map response probabilities and response speed onto constituent psychological process, and processing capacity is also assessed using response time distribution hazard functions. The findings include characteristic order effects that change systematically in magnitude and direction with changes in the magnitude and separation of the stimuli. After Hellström (1979, 2000), Sensation Weighting (SW) model analyses show that such order effects are reflected in the weighted accumulation of noisy information about the difference between stimulus values over time, and interindividual differences in weightings asymmetries are related to the relative processing capacity of participants. An account of sensation weighting based on the use of reference level information and maximization of signal-to-noise ratios is posited, which finds support from theoretically driven analyses of behavioral data.

  • 34.
    Pixton, Tonya S.
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Englund, Mats P.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Are you emotional or simply happy?: Detection and perceived intensity of anger, happiness, and emotionalityManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The purpose of the present study was to replicate the happy-superiority effect, which wasgreater for female than for male faces, found by Pixton and colleagues (in press, Pixton,Hellström, Englund, & Larsson, 2011) with a within-group study (Experiment 1) and abetween-group study (Experiment 2). All participants viewed the same pictures of male andfemale facial expressions (Tottenham, Tanaka, Leon et al., 2009) at three presentation times(12.50, 18.75, 25.00 ms), completing both a emotion-detection task (Task 1) and an emotionratingtask (Task 2). In Task 1, designed as a signal-detection task, participants answered yesif the face was emotional in Experiment 1, happy (happy-detection group) or angry (angrydetectiongroup) in Experiment 2, and no if not. In Task 2, participants rated each facestimulus on anger, happiness, and emotionality. Emotion sensitivities, d's, found in Task 1were adjusted using the differences in emotion-rating between each emotion-gender face andits neutral counterpart. For both Experiment 1 and 2, the d' values in Task 1 were greater forhappy faces than for angry faces, and “neutral” faces were not rated neutral in the differentemotion-type scales in Task 2. Taking this into account, the adjusted d' values were higher forthe happy-face group than for the angry-face group for the two longest times. Also, theadjusted d' values for angry-female faces remained lower than the other emotion-gender facecombinations. Together with results from Pixton’s (in press, 2011) between-groups study, thepresent within-participants results suggest that in emotion detection, happiness takesprecedence.

  • 35.
    Pixton, Tonya S.
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Englund, Mats P.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Perceived degree of facial happiness and the role of the particular stimuli2010Ingår i: Fechner Day 10: Proceedings of the 26th Annual Meeting of the International Society for Psychophysics / [ed] A. Bastianelli, & G. Vidotto, Padua, Italy: International Society for Psychophysics , 2010, s. 501-504Konferensbidrag (Refereegranskat)
    Abstract [en]

    The purpose of the present study was to elucidate further Pixton’s and colleagues (2007, 2008, 2009) results with a between-group study. Two groups (happy, angry) viewed pictures of facial expressions (Tottenham et al., 2009) with three presentation times (12.50, 18.75, 25.00 ms) and completed a detection (Part 1) and a rating (Part 2) task. In Part 1, participants answered “yes” if they thought the face was happy (happy-group) or angry (angry-group and “no” if not. In Part 2, they rated each face stimulus on each of three scales (angriness, happiness, emotionality). The d&#8242; values were higher for the happy-face group than for the angry-face group for the two longest times. “Neutral” faces were not rated equally neutral by the different groups. Together with Pixton and colleagues’ results, when investigating the detectability of emotions, account must be taken of the particular stimuli used, which has now been demonstrated in a between-groups and a within-participants study.

  • 36.
    Pixton, Tonya S.
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen, Perception och psykofysik.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen, Perception och psykofysik.
    Englund, Mats P.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen, Perception och psykofysik.
    Larsson, Maria
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen, Perception och psykofysik.
    The non-neutrality of 'neutral' faces: Effect on discriminability of emotional expressionsManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The main purpose of this study was to examine whether ‘neutral’ facial expressions are ratedas neutral. Facial expressions designated as angry, happy, and neutral were rated on anger,happiness, and emotionality. There were no significant differences in mean rating valuesbetween happy and angry faces on their relevant scales; neutral faces were rated somewhatangry and somewhat sad. Therefore, happy faces differed more from neutral faces than didangry faces. Furthermore, the sensitivity measures reported by Pixton (in press) were adjustedusing the mean difference value (MD) on each of the scale types between each genderemotioncombination and its neutral counterpart. The results showed that the general happysuperiorityand angry-male advantage effects disappeared, while angry-female faces weremore difficult to discriminate. These findings suggest that presumably ‘neutral’ faces are notnecessarily neutral, which ultimately may affect the discriminability of emotional facialexpressions.

  • 37.
    Selenius, Heidi
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Dåderman, Anna M
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Memory performance in dyslexic male juvenile delinquents convicted of severe offences does not differ from that in dyslexic male junior college students.2006Ingår i: World Journal of Biological Psychiatry, Vol. 7, nr 1, s. 41-50Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Background: There are different research approaches regarding the causes and possible overrepresentation of dyslexia in criminals. One approach focuses on sociological explanations such as under-stimulation at home, while another focuses on the importance of cognitive neurobiological dysfunctions. In several studies, poor memory for digits and poor verbal learning ability have been found in non-criminal dyslexics. Aim: To compare memory performance in two groups of dyslexics, namely, juvenile delinquents and junior college students, in order to discuss their dyslexic problems in the light of sociocultural and cognitive neurobiological approaches. Participants: Two groups of male adolescent dyslexics: 11 juvenile delinquents (mean age 18.55 years, SD = 2.07), all of them convicted for severe offences, and 11 junior college students (mean age 17.09 years, SD = 0.83). Results: Matched-samples t-tests indicate that there is no difference in memory performance between the two different groups of dyslexics, which supports the accuracy of the diagnoses of dyslexia in the group of juvenile delinquents. Conclusions: The present results show that the memory performance of dyslexic juvenile delinquents does not differ from that of dyslexic junior college students. A sociocultural approach, therefore, cannot plausibly explain the high prevalence of reading and writing difficulties among juvenile delinquents.

  • 38. Selenius, Heidi
    et al.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Dyslexia Prevalence in Forensic Psychiatric Patients: Dependence on Criteria and Background Factors2015Ingår i: Psychiatry, Psychology and Law, ISSN 1321-8719, E-ISSN 1934-1687, Vol. 22, nr 4, s. 586-598Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Research on dyslexia in forensic psychiatric patients is limited, and therefore one aim of this study was to assess the prevalence of dyslexia in a sample of forensic psychiatric patients by using different criteria. Another aim was to investigate how phonological-processing skills in these patients might be related to disadvantageous background factors and poor reading habits. Forensic psychiatric patients performed reading, writing and intelligence tests, as well as a battery of phonological processing tasks. They were also interviewed about reading habits and literacy conditions in their childhood homes. Data regarding the patients’ dyslexia diagnoses and backgrounds were collected from forensic psychiatric investigations and patient records. The results showed that 11–53% of the patients met the discrepancy criteria for dyslexia, whereas 50% fulfilled the phonological core deficit criterion. Neither disadvantageous background factors nor reading habits were related to phonological-processing skills.

  • 39.
    Selenius, Heidi
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Dyslexia prevalence in forensic psychiatric patients: Dependence on criteria and background factorsArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    Research on dyslexia in forensic psychiatric patients is limited, and therefore one aim of the present study was to assess the prevalence of dyslexia in a sample of forensic psychiatric patients by using different criteria. Another aim was to investigate how phonological processing skills in these patients might be related to disadvantageous background factors and poor reading habits. Forensic psychiatric patients performed reading, writing and intelligence tests, as well as a battery of phonological processing tasks. They were also interviewed about reading habits and literacy conditions in their childhood homes. Data regarding the patients’ dyslexia diagnoses and backgrounds were collected from forensic psychiatric investigations and patient records. The results showed that 11-53% of the patients met the discrepancy criteria for dyslexia, while 50% fulfilled the phonological core deficit criterion. Neither disadvantageous background factors nor reading habits were related to phonological processing skills.

  • 40.
    Selenius, Heidi
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Belfrage, Henrik
    Aggression and Risk of Future Violence in Forensic Psychiatric Patients with and without Dyslexia2011Ingår i: Dyslexia, ISSN 1076-9242, E-ISSN 1099-0909, Vol. 17, nr 2, s. 201-206Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dyslexia does not cause criminal behaviour, but it may worsen aggressive behaviour tendencies. In this study, aggressive behaviour and risk of future violence were compared between forensic psychiatric patients with and without dyslexia. Dyslexia was assessed using the Swedish phonological processing battery ‘The Pigeon’. The patients filled in the Aggression Questionnaire, and trained assessors performed the risk assessments using HCR-20 version 2. Patients with dyslexia self-reported more aggressive behaviour compared with those without dyslexia. There was only a nearly significant tendency (p=0.06) for the patients with dyslexia to receive higher scores in the HCR-20 compared with the patients without dyslexia, and phonological processing skills did not significantly predict aggression or risk of future violence. However, regression analyses demonstrated that poor phonological processing skills are a significant predictor of anger, which in turn significantly predicts risk of future violence.

  • 41. Östberg, Per
    et al.
    Fernaeus, Sven-Erik
    Hellström, Åke
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Psykologiska institutionen.
    Bogdanovic, Nenad
    Wahlund, Lars-Olof
    Impaired verb fluency: A sign of mild cognitive impairment.2005Ingår i: Brain and Language, ISSN 0093-934X, Vol. 95, nr 2, s. 273-279Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We assessed verb fluency vs. noun and letter-based fluency in 199 subjects referred for cognitive complaints including Subjective Cognitive Impairment, Mild Cognitive Impairment, and Alzheimer's disease. ANCOVAs and factor analyses identified verb, noun, and letter-based fluency as distinct tasks. Verb fluency performance in Mild Cognitive Impairment differed significantly from Subjective Cognitive Impairment and Alzheimer's disease. Reduced verb fluency thus appears to be a linguistic marker for incipient dementia. One possibility is that the verb fluency deficit in Mild Cognitive Impairment results from degenerative processes known to occur in the parahippocampal region.

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