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  • 1.
    Abdelhamid, Hani Nasser
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Assiut University, Egypt.
    El-Zohry, Ahmed M.
    Cong, Jiayan
    Thersleff, Thomas
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Karlsson, Martin
    Kloo, Lars
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Towards implementing hierarchical porous zeolitic imidazolate frameworks in dye-sensitized solar cells2019In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 6, no 7, article id 190723Article in journal (Refereed)
    Abstract [en]

    A one-pot method for encapsulation of dye, which can be applied for dye-sensitized solar cells (DSSCs), and synthesis of hierarchical porous zeolitic imidazolate frameworks (ZIF-8), is reported. The size of the encapsulated dye tunes the mesoporosity and surface area of ZIF-8. The mesopore size, Langmuir surface area and pore volume are 15 nm, 960-1500 m(2). g(-1) and 0.36-0.61 cm(3). g(-1), respectively. After encapsulation into ZIF-8, the dyes show longer emission lifetimes (greater than 4-8-fold) as compared to the corresponding non-encapsulated dyes, due to suppression of aggregation, and torsional motions.

  • 2.
    Enquist, Magnus
    et al.
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution.
    Ghirlanda, Stefano
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution. Brooklyn College, USA; Graduate Center of the City University of New York, USA.
    The power of associative learning and the ontogeny of optimal behaviour2016In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 3, no 11, article id 160734Article in journal (Refereed)
    Abstract [en]

    Behaving efficiently (optimally or near-optimally) is central to animals' adaptation to their environment. Much evolutionary biology assumes, implicitly or explicitly, that optimal behavioural strategies are genetically inherited, yet the behaviour of many animals depends crucially on learning. The question of how learning contributes to optimal behaviour is largely open. Here we propose an associative learning model that can learn optimal behaviour in a wide variety of ecologically relevant circumstances. The model learns through chaining, a term introduced by Skinner to indicate learning of behaviour sequences by linking together shorter sequences or single behaviours. Our model formalizes the concept of conditioned reinforcement (the learning process that underlies chaining) and is closely related to optimization algorithms from machine learning. Our analysis dispels the common belief that associative learning is too limited to produce ‘intelligent’ behaviour such as tool use, social learning, self-control or expectations of the future. Furthermore, the model readily accounts for both instinctual and learned aspects of behaviour, clarifying how genetic evolution and individual learning complement each other, and bridging a long-standing divide between ethology and psychology. We conclude that associative learning, supported by genetic predispositions and including the oft-neglected phenomenon of conditioned reinforcement, may suffice to explain the ontogeny of optimal behaviour in most, if not all, non-human animals. Our results establish associative learning as a more powerful optimizing mechanism than acknowledged by current opinion.

  • 3.
    Eriksson, Maertha
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Functional Morphology.
    Nylin, Sören
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Carlsson, Mikael A.
    Stockholm University, Faculty of Science, Department of Zoology, Functional Morphology.
    Insect brain plasticity: effects of olfactory input on neuropil size2019In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 6, no 8, article id 190875Article in journal (Refereed)
    Abstract [en]

    Insect brains are known to express a high degree of experience-dependent structural plasticity. One brain structure in particular, the mushroom body (MB), has been attended to in numerous studies as it is implicated in complex cognitive processes such as olfactory learning and memory. It is, however, poorly understood to what extent sensory input per se affects the plasticity of the mushroom bodies. By performing unilateral blocking of olfactory input on immobilized butterflies, we were able to measure the effect of passive sensory input on the volumes of antennal lobes (ALs) and MB calyces. We showed that the primary and secondary olfactory neuropils respond in different ways to olfactory input. ALs show absolute experience-dependency and increase in volume only if receiving direct olfactory input from ipsilateral antennae, while MB calyx volumes were unaffected by the treatment and instead show absolute age-dependency in this regard. We therefore propose that cognitive processes related to behavioural expressions are needed in order for the calyx to show experience-dependent volumetric expansions. Our results indicate that such experience-dependent volumetric expansions of calyces observed in other studies may have been caused by cognitive processes rather than by sensory input, bringing some causative clarity to a complex neural phenomenon.

  • 4.
    Ghirlanda, Stefano
    et al.
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution. Brooklyn College, USA; Graduate Center of the City University of New York, USA.
    Lind, Johan
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution.
    Enquist, Magnus
    Stockholm University, Faculty of Science, Department of Zoology. Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution.
    Memory for stimulus sequences: a divide between humans and other animals?2017In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 4, no 6, article id 161011Article in journal (Refereed)
    Abstract [en]

    Humans stand out among animals for their unique capacities in domains such as language, culture and imitation, yet it has been difficult to identify cognitive elements that are specifically human. Most research has focused on how information is processed after it is acquired, e.g. in problem solving or 'insight' tasks, but we may also look for species differences in the initial acquisition and coding of information. Here, we show that non-human species have only a limited capacity to discriminate ordered sequences of stimuli. Collating data from 108 experiments on stimulus sequence discrimination (1540 data points from 14 bird and mammal species), we demonstrate pervasive and systematic errors, such as confusing a red-green sequence of lights with green-red and green-green sequences. These errors can persist after thousands of learning trials in tasks that humans learn to near perfection within tens of trials. To elucidate the causes of such poor performance, we formulate and test a mathematical model of non-human sequence discrimination, assuming that animals represent sequences as unstructured collections of memory traces. This representation carries only approximate information about stimulus duration, recency, order and frequency, yet our model predicts non-human performance with a 5.9% mean absolute error across 68 datasets. Because human-level cognition requires more accurate encoding of sequential information than afforded by memory traces, we conclude that improved coding of sequential information is a key cognitive element that may set humans apart from other animals.

  • 5. Gilbert, James
    et al.
    Uggla, Caroline
    Stockholm University, Faculty of Social Sciences, Department of Sociology. University College London, UK.
    Mace, Ruth
    Knowing your neighbourhood: local ecology and personal experience predict neighbourhood perceptions in Belfast, Northern Ireland2016In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 3, no 12, article id 160468Article in journal (Refereed)
    Abstract [en]

    Evolutionary theory predicts that humans should adjust their life-history strategies in response to local ecological threats and opportunities in order to maximize their reproductive success. Cues representing threats to individuals' lives and health in modern, Western societies may come in the form of local ages at death, morbidity rate and crime rate in their local area, whereas the adult sex ratio represents a measure of the competition for reproductive partners. These characteristics are believed to have a strong influence over a wide range of behaviours, but whether they are accurately perceived has not been robustly tested. Here, we investigate whether perceptions of four neighbourhood characteristics are accurate across eight neighbourhoods in Belfast, Northern Ireland. We find that median age at death and morbidity rates are accurately perceived, whereas adult sex ratios and crime rates are not. We suggest that both neighbourhood characteristics and personal experiences contribute to the formation of perceptions. This should be considered by researchers looking for associations between area-level factors.

  • 6.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Shifts in rotifer life history in response to stable isotope enrichment: testing theories of isotope effects on organismal growth2017In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 4, no 3, article id 160810Article in journal (Refereed)
    Abstract [en]

    In ecology, stable isotope labelling is commonly used for tracing material transfer in trophic interactions, nutrient budgets and biogeochemical processes. The main assumption in this approach is that the enrichment with a heavy isotope has no effect on the organism growth and metabolism. This assumption is, however, challenged by theoretical considerations and experimental studies on kinetic isotope effects in vivo. Here, I demonstrate profound changes in life histories of the rotifer Brachionus plicatilis fed N-15-enriched algae (0.4-5.0 at%); i.e. at the enrichment levels commonly used in ecological studies. These findings support theoretically predicted effects of heavy isotope enrichment on growth, metabolism and ageing in biological systems and underline the importance of accounting for such effects when using stable isotope labelling in experimental studies.

  • 7. Hardwicke, Tom E.
    et al.
    Mathur, Maya B.
    MacDonald, Kyle
    Nilsonne, Gustav
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Stanford University, USA; Karolinska Institutet, Sweden.
    Banks, George C.
    Kidwell, Mallory C.
    Mohr, Alicia Hofelich
    Clayton, Elizabeth
    Yoon, Erica J.
    Tessler, Michael Henry
    Lenne, Richie L.
    Altman, Sara
    Long, Bria
    Frank, Michael C.
    Data availability, reusability, and analytic reproducibility: evaluating the impact of a mandatory open data policy at the journal Cognition2018In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 5, no 8, article id 180448Article in journal (Refereed)
    Abstract [en]

    Access to data is a critical feature of an efficient, progressive and ultimately self-correcting scientific ecosystem. But the extent to which in-principle benefits of data sharing are realized in practice is unclear. Crucially, it is largely unknown whether published findings can be reproduced by repeating reported analyses upon shared data ('analytic reproducibility'). To investigate this, we conducted an observational evaluation of a mandatory open data policy introduced at the journal Cognition. Interrupted time-series analyses indicated a substantial post-policy increase in data available statements (104/417, 25% pre-policy to 136/ 174, 78% post-policy), although not all data appeared reusable (23/ 104, 22% pre-policy to 85/136, 62%, post-policy). For 35 of the articles determined to have reusable data, we attempted to reproduce 1324 target values. Ultimately, 64 values could not be reproduced within a 10% margin of error. For 22 articles all target values were reproduced, but 11 of these required author assistance. For 13 articles at least one value could not be reproduced despite author assistance. Importantly, there were no clear indications that original conclusions were seriously impacted. Mandatory open data policies can increase the frequency and quality of data sharing. However, suboptimal data curation, unclear analysis specification and reporting errors can impede analytic reproducibility, undermining the utility of data sharing and the credibility of scientific findings.

  • 8. Ingre, Michael
    et al.
    Nilsonne, Gustav
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden; Stanford University, USA.
    Estimating statistical power, posterior probability and publication bias of psychological research using the observed replication rate2018In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 5, no 9, article id 181190Article in journal (Refereed)
    Abstract [en]

    In this paper, we show how Bayes' theorem can be used to better understand the implications of the 36% reproducibility rate of published psychological findings reported by the Open Science Collaboration. We demonstrate a method to assess publication bias and show that the observed reproducibility rate was not consistent with an unbiased literature. We estimate a plausible range for the prior probability of this body of research, suggesting expected statistical power in the original studies of 48-75%, producing (positive) findings that were expected to be true 41-62% of the time. Publication bias was large, assuming a literature with 90% positive findings, indicating that negative evidence was expected to have been observed 55-98 times before one negative result was published. These findings imply that even when studied associations are truly NULL, we expect the literature to be dominated by statistically significant findings.

  • 9.
    Karlson, Agnes M. L.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Reutgard, Martin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Garbaras, Andrius
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Isotopic niche reflects stress-induced variability in physiological status2018In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 5, no 2, article id 171398Article in journal (Refereed)
    Abstract [en]

    The isotopic niche has become an established concept in trophic ecology. However, the assumptions behind this approach have rarely been evaluated. Evidence is accumulating that physiological stress can affect both magnitude and inter-individual variability of the isotopic signature in consumers via alterations in metabolic pathways. We hypothesized that stress factors (inadequate nutrition, parasite infestations, and exposure to toxic substances or varying oxygen conditions) might lead to suboptimal physiological performance and altered stable isotope signatures. The latter can be misinterpreted as alterations in isotopic niche. This hypothesis was tested by inducing physiological stress in the deposit-feeding amphipod Monoporeia affinis exposed to either different feeding regimes or contaminated sediments. In the amphipods, we measured body condition indices or reproductive output to assess growth status and delta C-13 and delta N-15 values to derive isotope niche metrics. As hypothesized, greater isotopic niche estimates were derived for the stressed animals compared to the control groups. Moreover, the delta N-15 values were influenced by body size, reproductive status and parasite infestations, while delta C-13 values were influenced by body size, oxygen conditions and survival. Using regression analysis with isotope composition and growth variables as predictors, we were able to discriminate between the amphipods exposed to nutritionally or chemically stressful conditions and those in the control groups. Thus, interpretation of isotopic niche can be confounded by natural or anthropogenic stressors that may induce an apparent change in isotopic niche. These findings stress the importance of including measures of growth and health status when evaluating stable isotope data in food web studies.

  • 10. Klein, E. S.
    et al.
    Barbier, M. R.
    Watson, James R.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Oregon State University, USA.
    The dual impact of ecology and management on social incentives in marine common-pool resource systems2017In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 4, no 8, article id 170740Article in journal (Refereed)
    Abstract [en]

    Understanding how and when cooperative human behaviour forms in common-pool resource systems is critical to illuminating social-ecological systems and designing governance institutions that promote sustainable resource use. Before assessing the full complexity of social dynamics, it is essential to understand, concretely and mechanistically, how resource dynamics and human actions interact to create incentives and pay-offs for social behaviours. Here, we investigated how such incentives for information sharing are affected by spatial dynamics and management in a common-pool resource system. Using interviews with fishermen to inform an agent-based model, we reveal generic mechanisms through which, for a given ecological setting characterized by the spatial dynamics of the resource, the two 'human factors' of information sharing and management may heterogeneously impact various members of a group for whom theory would otherwise predict the same strategy. When users can deplete the resource, these interactions are further affected by the management approach. Finally, we discuss the implications of alternative motivations, such as equity among fishermen and consistency of the fleet's output. Our results indicate that resource spatial dynamics, form of management and level of depletion can interact to alter the sociality of people in common-pool resource systems, providing necessary insight for future study of strategic decision processes.

  • 11.
    Lind, Johan
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for Cultural Evolution.
    What can associative learning do for planning?2018In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 5, no 11, article id 180778Article in journal (Refereed)
    Abstract [en]

    There is a new associative learning paradox. The power of associative learning for producing flexible behaviour in non-human animals is downplayed or ignored by researchers in animal cognition, whereas artificial intelligence research shows that associative learning models can beat humans in chess. One phenomenon in which associative learning often is ruled out as an explanation for animal behaviour is flexible planning. However, planning studies have been criticized and questions have been raised regarding both methodological validity and interpretations of results. Due to the power of associative learning and the uncertainty of what causes planning behaviour in non-human animals, I explored what associative learning can do for planning. A previously published sequence learning model which combines Pavlovian and instrumental conditioning was used to simulate two planning studies, namely Mulcahy & Call 2006 'Apes save tools for future use.' Science 312, 1038-1040 and Kabadayi & Osvath 2017 'Ravens parallel great apes in flexible planning for tool-use and bartering. 'Science 357, 202-204. Simulations show that behaviour matching current definitions of flexible planning can emerge through associative learning. Through conditioned reinforcement, the learning model gives rise to planning behaviour by learning that a behaviour towards a current stimulus will produce high value food at a later stage; it can make decisions about future states not within current sensory scope. The simulations tracked key patterns both between and within studies. It is concluded that one cannot rule out that these studies of flexible planning in apes and corvids can be completely accounted for by associative learning. Future empirical studies of flexible planning in non-human animals can benefit from theoretical developments within artificial intelligence and animal learning.

  • 12.
    Lind, Johan
    et al.
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies. Stockholm University, Faculty of Science, Department of Zoology.
    Ghirlanda, Stefano
    Enquist, Magnus
    Stockholm University, Faculty of Science, Department of Zoology.
    Social learning through associative processes: a computational theory2019In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 6, no 3, article id 181777Article in journal (Refereed)
    Abstract [en]

    Social transmission of information is a key phenomenon in the evolution of behaviour and in the establishment of traditions and culture. The diversity of social learning phenomena has engendered a diverse terminology and numerous ideas about underlying learning mechanisms, at the same time that some researchers have called for a unitary analysis of social learning in terms of associative processes. Leveraging previous attempts and a recent computational formulation of associative learning, we analyse the following learning scenarios in some generality: learning responses to social stimuli, including learning to imitate; learning responses to non-social stimuli; learning sequences of actions; learning to avoid danger. We conceptualize social learning as situations in which stimuli that arise from other individuals have an important role in learning. This role is supported by genetic predispositions that either cause responses to social stimuli or enable social stimuli to reinforce specific responses. Simulations were performed using a new learning simulator program. The simulator is publicly available and can be used for further theoretical investigations and to guide empirical research of learning and behaviour. Our explorations show that, when guided by genetic predispositions, associative processes can give rise to a wide variety of social learning phenomena, such as stimulus and local enhancement, contextual imitation and simple production imitation, observational conditioning, and social and response facilitation. In addition, we clarify how associative mechanisms can result in transfer of information and behaviour from experienced to naive individuals.

  • 13.
    Liuzza, Marco Tullio
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Personality, Social and Developmental Psychology. University of Catanzaro, Italy; University of Rome, Italy; RCCS Santa Lucia Foundation, Italy.
    Lindholm, Torun
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Personality, Social and Developmental Psychology.
    Hawley, Caitlin B.
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Perception and psychophysics.
    Gustafsson Sendén, Marie
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Personality, Social and Developmental Psychology.
    Ekström, Ingrid
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Perception and psychophysics.
    Olsson, Mats J.
    Olofsson, Jonas K.
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Perception and psychophysics. Swedish Collegium for Advanced Study, Sweden.
    Body odour disgust sensitivity predicts authoritarian attitudes2018In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 5, no 2, article id 171091Article in journal (Refereed)
    Abstract [en]

    Authoritarianism has resurfaced as a research topic in political psychology, as it appears relevant to explain current political trends. Authoritarian attitudes have been consistently linked to feelings of disgust, an emotion that is thought to have evolved to protect the organism from contamination. We hypothesized that body odour disgust sensitivity (BODS) might be associated with authoritarianism, as chemo-signalling is a primitive system for regulating interpersonal contact and disease avoidance, which are key features also in authoritarianism. We used well-validated scales for measuring BODS, authoritarianism and related constructs. Across two studies, we found that BODS is positively related to authoritarianism. In a third study, we showed a positive association between BODS scores and support for Donald Trump, who, at the time of data collection, was a presidential candidate with an agenda described as resonating with authoritarian attitudes. Authoritarianism fully explained the positive association between BODS and support for Donald Trump. Our findings highlight body odour disgust as a new and promising domain in political psychology research. Authoritarianism and BODS might be part of the same disease avoidance framework, and our results contribute to the growing evidence that contemporary social attitudes might be rooted in basic sensory functions.

  • 14. Meyer, Kristina
    et al.
    Garzón, Benjamin
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Lövdén, Martin
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Hildebrandt, Andrea
    Are global and specific interindividual differences in cortical thickness associated with facets of cognitive abilities, including face cognition?2019In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 6, no 7, article id 180857Article in journal (Refereed)
    Abstract [en]

    Face cognition (FC) is a specific ability that cannot be fully explained by general cognitive functions. Cortical thickness (CT) is a neural correlate of performance and learning. In this registered report, we used data from the Human Connectome Project (HCP) to investigate the relationship between CT in the core brain network of FC and performance on a psychometric task battery, including tasks with facial content. Using structural equation modelling (SEM), we tested the existence of face-specific interindividual differences at behavioural and neural levels. The measurement models include general and face-specific factors of performance and CT. There was no face-specificity in CT in functionally localized areas. In post hoc analyses, we compared the preregistered, small regions of interest (ROIs) to larger, non-individualized ROIs and identified a face-specific CT factor when large ROIs were considered. We show that this was probably due to low reliability of CT in the functional localization (intra-class correlation coefficients (ICC) between 0.72 and 0.85). Furthermore, general cognitive ability, but not face-specific performance, could be predicted by latent factors of CT with a small effect size. In conclusion, for the core brain network of FC, we provide exploratory evidence (in need of cross-validation) that areas of the cortex sharing a functional purpose did also share morphological properties as measured by CT.

  • 15.
    Nilsonne, Gustav
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Renberg, Adam
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Tamm, Sandra
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Lekander, Mats
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Health at the ballot box: disease threat does not predict attractiveness preference in British politicians2016In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 3, article id 160049Article in journal (Refereed)
    Abstract [en]

    According to disease avoidance theory, selective pressures have shaped adaptive behaviours to avoid people who might transmit infections. Such behavioural immune defence strategies may have social and societal consequences. Attractiveness is perceived as a heuristic cue of good health, and the relative importance of attractiveness is predicted to increase during high disease threat. Here, we investigated whether politicians' attractiveness is more important for electoral success when disease threat is high, in an effort to replicate earlier findings from the USA. We performed a cross-sectional study of 484 members of the House of Commons from England and Wales. Publicly available sexiness ratings (median 5883 ratings/politician) were regressed on measures of disease burden, operationalized as infant mortality, life expectancy and self-rated health. Infant mortality in parliamentary constituencies did not significantly predict sexiness of elected members of parliament (p = 0.08), nor did life expectancy (p = 0.06), nor self-rated health (p = 0.55). Subsample analyses failed to provide further support for the hypothesis. In conclusion, an attractive leader effect was not amplified by disease threat in the UK and these results did not replicate those of earlier studies from the USA concerning the relationship between attractiveness, disease threat and voting preference.

  • 16.
    Nilsonne, Gustav
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Tamm, Sandra
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Golkar, Armita
    Sörman, Karolina
    Howner, Katarina
    Kristiansson, Marianne
    Olsson, Andreas
    Ingvar, Martin
    Petrovic, Predrag
    Effects of 25 mg oxazepam on emotional mimicry and empathy for pain: a randomized controlled experiment2017In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 4, no 3, article id 160607Article in journal (Refereed)
    Abstract [en]

    Emotional mimicry and empathy are mechanisms underlying social interaction. Benzodiazepines have been proposed to inhibit empathy and promote antisocial behaviour. First, we aimed to investigate the effects of oxazepam on emotional mimicry and empathy for pain, and second, we aimed to investigate the association of personality traits to emotional mimicry and empathy. Participants (n= 76) were randomized to 25mg oxazepam or placebo. Emotional mimicry was examined using video clips with emotional expressions. Empathy was investigated by pain stimulating the participant and a confederate. We recorded self-rated experience, activity in major zygomatic and superciliary corrugator muscles, skin conductance, and heart rate. In the mimicry experiment, oxazepam inhibited corrugator activity. In the empathy experiment, oxazepam caused increased self-rated unpleasantness and skin conductance. However, oxazepam specifically inhibited neither emotional mimicry nor empathy for pain. Responses in both experiments were associated with self-rated empathic, psychopathic and alexithymic traits. The present results do not support a specific effect of 25mg oxazepam on emotional mimicry or empathy.

  • 17.
    Nordström, Henrik
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Perception and psychophysics.
    Laukka, Petri
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Cognitive psychology.
    Thingujam, Nutankumar S.
    Schubert, Emery
    Elfenbein, Hillary Anger
    Emotion appraisal dimensions inferred from vocal expressions are consistent across cultures: a comparison between Australia and India2017In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 4, no 11, article id 170912Article in journal (Refereed)
    Abstract [en]

    This study explored the perception of emotion appraisal dimensions on the basis of speech prosody in a cross-cultural setting. Professional actors from Australia and India vocally portrayed different emotions (anger, fear, happiness, pride, relief, sadness, serenity and shame) by enacting emotion-eliciting situations. In a balanced design, participants from Australia and India then inferred aspects of the emotion-eliciting situation from the vocal expressions, described in terms of appraisal dimensions (novelty, intrinsic pleasantness, goal conduciveness, urgency, power and norm compatibility). Bayesian analyses showed that the perceived appraisal profiles for the vocally expressed emotions were generally consistent with predictions based on appraisal theories. Few group differences emerged, which suggests that the perceived appraisal profiles are largely universal. However, some differences between Australian and Indian participants were also evident, mainly for ratings of norm compatibility. The appraisal ratings were further correlated with a variety of acoustic measures in exploratory analyses, and inspection of the acoustic profiles suggested similarity across groups. In summary, results showed that listeners may infer several aspects of emotion-eliciting situations from the non-verbal aspects of a speaker's voice. These appraisal inferences also seem to be relatively independent of the cultural background of the listener and the speaker.

  • 18. Romaniuk, Andrzej A.
    et al.
    Shepherd, Alexandra N.
    Clarke, David V.
    Sheridan, Alison J.
    Fraser, Sheena
    Bartosiewicz, László
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies.
    Herman, Jeremy S.
    Rodents: food or pests in Neolithic Orkney2016In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 3, no 10, article id 160514Article in journal (Refereed)
    Abstract [en]

    Rodents have important effects on contemporary human societies, sometimes providing a source of food but more often as agricultural pests, or as vectors and reservoirs of disease. Skeletal remains of rodents are commonly found in archaeological assemblages from around the world, highlighting their potential importance to ancient human populations. However, there are few studies of the interactions between people and rodents at such sites and most of these are confined to locations where rodents have formed a part of the recent diet. Here we compare the accumulation pattern of rodent remains from four locations within and adjacent to the renowned Neolithic site of Skara Brae, Orkney, showing that those within the settlement itself were the result of deliberate human activity. The accumulation and nature of burnt bones, incorporated over an extended period within deposits of household waste, indicate that rodents were used as a nutritional resource and may have been the subject of early pest control. We, therefore, provide the first evidence for the exploitation or control of rodents by the Neolithic inhabitants of Europe.

  • 19. Romenskyy, Maksym
    et al.
    Herbert-Read, James E.
    Stockholm University, Faculty of Science, Department of Zoology. Uppsala University, Sweden.
    Ward, Ashley J. W.
    Sumpter, David J. T.
    Body size affects the strength of social interactions and spatial organization of a schooling fish (Pseudomugil signifer)2017In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 4, no 4, article id 161056Article in journal (Refereed)
    Abstract [en]

    While a rich variety of self-propelled particle models propose to explain the collective motion of fish and other animals, rigorous statistical comparison between models and data remains a challenge. Plausible models should be flexible enough to capture changes in the collective behaviour of animal groups at their different developmental stages and group sizes. Here, we analyse the statistical properties of schooling fish (Pseudomugil signifer) through a combination of experiments and simulations. We make novel use of a Boltzmann inversion method, usually applied in molecular dynamics, to identify the effective potential of the mean force of fish interactions. Specifically, we show that larger fish have a larger repulsion zone, but stronger attraction, resulting in greater alignment in their collective motion. We model the collective dynamics of schools using a self-propelled particle model, modified to include varying particle speed and a local repulsion rule. We demonstrate that the statistical properties of the fish schools are reproduced by our model, thereby capturing a number of features of the behaviour and development of schooling fish.

  • 20.
    Sundelin, Tina
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Biological psychology. Karolinska Institutet, Sweden.
    Lekander, Mats
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Sorjonen, Kimmo
    Axelsson, John
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Negative effects of restricted sleep on facial appearance and social appeal2017In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 4, no 5, article id 160918Article in journal (Refereed)
    Abstract [en]

    The importance of assessing evolutionarily relevant social cues suggests that humans should be sensitive to others' sleep history, as this may indicate something about their health as well as their capacity for social interaction. Recent findings show that acute sleep deprivation and looking tired are related to decreased attractiveness and health, as perceived by others. This suggests that one might also avoid contact with sleep-deprived, or sleepy-looking, individuals, as a strategy to reduce health risk and poor interactions. In this study, 25 participants (14 females, age range 18-47 years) were photographed after 2 days of sleep restriction and after normal sleep, in a balanced design. The photographs were rated by 122 raters (65 females, age range 18-65 years) on how much they would like to socialize with the participants. They also rated participants' attractiveness, health, sleepiness and trustworthiness. The results show that raters were less inclined to socialize with individuals who had gotten insufficient sleep. Furthermore, when sleep-restricted, participants were perceived as less attractive, less healthy and more sleepy. There was no difference in perceived trustworthiness. These findings suggest that naturalistic sleep loss can be detected in a face and that people are less inclined to interact with a sleep-deprived individual.

  • 21.
    Tamm, Sandra
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Nilsonne, Gustav
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden .
    Schwarz, Johanna
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Golkar, Armita
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Biological psychology. Karolinska Institutet, Sweden.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Petrovic, Predrag
    Fischer, Håkan
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Biological psychology.
    Åkerstedt, Torbjörn
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Lekander, Mats
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Sleep restriction caused impaired emotional regulation without detectable brain activation changes—a functional magnetic resonance imaging study2019In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 6, no 3, article id 181704Article in journal (Refereed)
    Abstract [en]

    Sleep restriction has been proposed to cause impaired emotional processing and emotional regulation by inhibiting top-down control from prefrontal cortex to amygdala. Intentional emotional regulation after sleep restriction has, however, never been studied using brain imaging. We aimed here to investigate the effect of partial sleep restriction on emotional regulation through cognitive reappraisal. Forty-seven young (age 20–30) and 33 older (age 65–75) participants (38/23 with complete data and successful sleep intervention) performed a cognitive reappraisal task during fMRI after a night of normal sleep and after restricted sleep (3 h). Emotional downregulation was associated with significantly increased activity in the dorsolateral prefrontal cortex (pFWE < 0.05) and lateral orbital cortex (pFWE < 0.05) in young, but not in older subjects. Sleep restriction was associated with a decrease in self-reported regulation success to negative stimuli (p< 0.01) and a trend towards perceiving all stimuli as less negative (p = 0.07) in young participants. No effects of sleep restriction on brain activity nor connectivity were found in either age group. In conclusion, our data do not support the idea of a prefrontal-amygdala disconnect after sleep restriction, and neural mechanisms underlying behavioural effects on emotional regulation after insufficient sleep require further investigation.

  • 22. Ward, Ashley J. W.
    et al.
    Schaerf, Timothy M.
    Herbert-Read, James E.
    Stockholm University, Faculty of Science, Department of Zoology. Uppsala University, Sweden.
    Morrell, Lesley
    Sumpter, David J. T.
    Webster, Mike M.
    Local interactions and global properties of wild, free-ranging stickleback shoals2017In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 4, no 7, article id 170043Article in journal (Refereed)
    Abstract [en]

    Collective motion describes the global properties of moving groups of animals and the self-organized, coordinated patterns of individual behaviour that produce them. We examined the group-level patterns and local interactions between individuals in wild, free-ranging shoals of three-spine sticklebacks, Gasterosteus aculeatus. Our data reveal that the highest frequencies of near-neighbour encounters occur at between one and two body lengths from a focal fish, with the peak frequency alongside a focal individual. Fish also show the highest alignment with these laterally placed individuals, and generally with animals in front of themselves. Furthermore, fish are more closely matched in size, speed and orientation to their near neighbours than to more distant neighbours, indicating local organization within groups. Among the group-level properties reported here, we find that polarization is strongly influenced by group speed, but also the variation in speed among individuals and the nearest neighbour distances of group members. While we find no relationship between group order and group size, we do find that larger groups tend to have lower nearest neighbour distances, which in turn may be important in maintaining group order.

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