Although intranasal oxytocin administration to tap into central functions is the most commonly used non-invasive means for exploring oxytocin’s role in human cognition and behavior, the way by which intranasal oxytocin acts on the brain is not yet fully understood. Recent research suggests that brain regions densely populated with oxytocin receptors may play a central role in intranasal oxytocin’s action mechanisms in the brain. In particular, intranasal oxytocin may act directly on (subcortical) regions rich in oxytocin receptors via binding to these receptors while only indirectly affecting other (cortical) regions via their neural connections to oxytocin receptor-enriched regions. Aligned with this notion, the current study adopted a novel approach to test 1) whether the connections between oxytocin receptor-enriched regions (i.e., the thalamus, pallidum, caudate nucleus, putamen, and olfactory bulbs) and other regions in the brain were responsive to intranasal oxytocin administration, and 2) whether oxytocin-induced effects varied as a function of age. Forty-six young (24.96 ± 3.06 years) and 44 older (69.89 ± 2.99 years) participants were randomized, in a double-blind procedure, to self-administer either intranasal oxytocin or placebo before resting-state fMRI. Results supported age-dependency in the effects of intranasal oxytocin administration on connectivity between oxytocin receptor-enriched regions and other regions in the brain. Specifically, compared to placebo, oxytocin decreased both connectivity density and connectivity strength of the thalamus for young participants while it increased connectivity density and connectivity strength of the caudate for older participants. These findings inform the mechanisms underlying the effects of exogenous oxytocin on brain function and highlight the importance of age in these processes.

Researchers have proposed that variation in sex hormones across the menstrual cycle modulate the ability to recognize emotions in others. Existing research suggests that accuracy is higher during the follicular phase and ovulation compared to the luteal phase, but findings are inconsistent. Using a repeated measures design with a sample of healthy naturally cycling women (N = 63), we investigated whether emotion recognition accuracy varied between the follicular and luteal phases, and whether accuracy related to levels of estrogen (estradiol) and progesterone. Two tasks assessed recognition of a range of positive and negative emotions via brief video recordings presented in visual, auditory, and multimodal blocks, and non-linguistic vocalizations (e.g., laughter, sobs, and sighs). Multilevel models did not show differences in emotion recognition between cycle phases. However, coefficients for estrogen were significant for both emotion recognition tasks. Higher within-person levels of estrogen predicted lower accuracy, whereas higher between-person estrogen levels predicted greater accuracy. This suggests that in general having higher estrogen levels increases accuracy, but that higher-than-usual estrogen at a given time decreases it. Within-person estrogen further interacted with cycle phase for both tasks and showed a quadratic relationship with accuracy for the multimodal task. In particular, women with higher levels of estrogen were more accurate in the follicular phase and middle of the menstrual cycle. We propose that the differing role of within- and between-person hormone levels could explain some of the inconsistency in previous findings.

Studies have reported substantial variability in emotion recognition ability (ERA) – an important social skill – but possible neural underpinnings for such individual differences are not well understood. This functional magnetic resonance imaging (fMRI) study investigated neural responses during emotion recognition in young adults (N=49) who were selected for inclusion based on their performance (high or low) during previous testing of ERA. Participants were asked to judge brief video recordings in a forced-choice emotion recognition task, wherein stimuli were presented in visual, auditory and multimodal (audiovisual) blocks. Emotion recognition rates during brain scanning confirmed that individuals with high (vs. low) ERA received higher accuracy for all presentation blocks. fMRI-analyses focused on key regions of interest (ROIs) involved in the processing of multimodal emotion expressions, based on previous meta-analyses. In neural response to emotional stimuli contrasted with neutral stimuli, individuals with high (vs. low) ERA showed higher activation in the following ROIs during the multimodal condition: right middle superior temporal gyrus (mSTG), right posterior superior temporal sulcus (PSTS), and right inferior frontal cortex (IFC). Overall, results suggest that individual variability in ERA may be reflected across several stages of decisional processing, including extraction (mSTG), integration (PSTS) and evaluation (IFC) of emotional information.

Age-related differences in emotion recognition have predominantly been investigated using static pictures of facial expressions, and positive emotions beyond happiness have rarely been included. The current study instead used dynamic facial and vocal stimuli, and included a wider than usual range of positive emotions. In Task 1, younger and older adults were tested for their abilities to recognize 12 emotions from brief video recordings presented in visual, auditory, and multimodal blocks. Task 2 assessed recognition of 18 emotions conveyed by non-linguistic vocalizations (e.g., laughter, sobs, and sighs). Results from both tasks showed that younger adults had significantly higher overall recognition rates than older adults. In Task 1, significant group differences (younger > older) were only observed for the auditory block (across all emotions), and for expressions of anger, irritation, and relief (across all presentation blocks). In Task 2, significant group differences were observed for 6 out of 9 positive, and 8 out of 9 negative emotions. Overall, results indicate that recognition of both positive and negative emotions show age-related differences. This suggests that the age-related positivity effect in emotion recognition may become less evident when dynamic emotional stimuli are used and happiness is not the only positive emotion under study.

Individuals vary in emotion recognition ability (ERA), but the causes and correlates of this variability are not well understood. Previous studies have largely focused on unimodal facial or vocal expressions and a small number of emotion categories, which may not reflect how emotions are expressed in everyday interactions. We investigated individual differences in ERA using a brief test containing dynamic multimodal (facial and vocal) expressions of 5 positive and 7 negative emotions (the ERAM test). Study 1 (N = 593) showed that ERA was positively correlated with emotional understanding, empathy, and openness, and negatively correlated with alexithymia. Women also had higher ERA than men. Study 2 was conducted online and replicated the recognition rates from Study 1 (which was conducted in lab) in a different sample (N = 106). Study 2 also showed that participants who had higher ERA were more accurate in their meta-cognitive judgments about their own accuracy. Recognition rates for visual, auditory, and audio-visual expressions were substantially correlated in both studies. Results provide further clues about the underlying structure of ERA and its links to broader affective processes. The ERAM test can be used for both lab and online research, and is freely available for academic research.

Social perception plays a key role in our everyday interactions. It encompasses the ability to identify, understand, and react to the social cues that others express. However, how we process this social and emotional information changes with age and generally speaking, aging brings about a decline in this process, often leading to isolation, loneliness and reduced interpersonal functioning. The overall aim of this thesis was to study the underlying mechanisms of adult age-related changes in socioemotional perception, specifically of social attribute evaluation and emotion recognition. This was done in three studies.

Study I explored age-related differences in the evaluation of seven common social attributes (attractiveness, competence, dominance, extroversion, likeability, threat, and trustworthiness) from computer-generated faces of varying intensity. Older adults rated faces as more attractive across all intensity levels, relative to their younger counterparts. Older adults also rated faces displaying low intensity of likeability as more likeable. Study II examined the effects of age on emotion recognition of positive and negative dynamic visual and auditory emotional expressions presented alone or in combination, and in nonlinguistic vocalizations. Older compared to younger adults showed diminished overall recognition accuracy and age-related differences were mainly observed in the auditory modality. Older adults also showed difficulties in recognizing anger, irritation, and relief expressions. In the case of the nonlinguistic vocalizations, age-related differences were observed for most emotions, regardless of valence. Study III investigated whether a single dose intranasal oxytocin facilitated the recognition of negative emotions from dynamic multimodal expressions and explored the neural correlates of this process with functioning magnetic resonance imaging. Behaviorally, older showed diminished recognition accuracy compared to younger adults but no oxytocin effects were found. Neurally, oxytocin caused brain activity reductions in the fusiform gyrus, dorsomedial prefrontal cortex, and medial orbitofrontal cortex.

The findings of this thesis provide a more nuanced picture of how aging may influence socioemotional perception. Collectively, the findings suggest age comparability for most emotion categories and social attributes. These result patterns may conceivably be due to the computer-generated faces, several positive emotion expressions, and dynamic multimodal stimuli that were included in the studies. The findings also give a neuropsychobiological perspective to socioemotional processing in late adulthood through oxytocin intervention.

Normal adult aging is associated with decline in some socioemotional abilities, such as the ability to recognize emotions in others, and age-related neurobiological processes may contribute to these deficits. There is increasing evidence that the neuropeptide oxytocin plays a key role in social cognition, including emotion recognition. The mechanisms through which oxytocin promotes emotion recognition are not well understood yet, and particularly in aging. In a randomized, double-blind, placebo-controlled within-subjects design, we investigated the extent to which a single dose of 40 IU of intranasal oxytocin facilitates emotion recognition in 40 younger (M = 24.90 yrs., SD = 2.97, 48% women) and 40 older (M = 69.70 yrs., SD = 2.99, 55% women) men and women. During two fMRI sessions, participants viewed dynamic positive and negative emotional displays. Preliminary analyses show that younger participants recognized positive and negative emotions more accurately than older participants (p < .001), with this behavioral effect not modulated by oxytocin. In the brain data, however, we found an age x treatment interaction in medial prefrontal cortex (xyz [14, 14, 6], p = .007) and superior temporal gyrus (xyz [53, 9, 2], p = .031). In particular, oxytocin (vs. placebo) reduced activity in these regions for older participants, while it enhanced activity in these regions for younger participants. In line with previous research, these findings support the notion that the effects of oxytocin vary by context and individual factors (e.g., social proficiency, age).

In everyday life throughout the life span, people frequently evaluate faces to obtain information crucial for social interactions. We investigated age-related differences in judgments of a wide range of social attributes based on facial appearance. Seventy-one younger and 60 older participants rated 196 computer-generated faces that systematically varied in facial features such as shape and reflectance to convey different intensity levels of seven social attributes (i.e., attractiveness, competence, dominance, extraversion, likeability, threat, and trustworthiness). Older compared to younger participants consistently gave higher attractiveness ratings to faces representing both high and low levels of attractiveness. Older participants were also less sensitive to the likeability of faces and tended to evaluate faces representing low likeability as more likable. The age groups did, however, not differ substantially in their evaluations of the other social attributes. Results are in line with previous research showing that aging is associated with preference toward positive and away from negative information and extend this positivity effect to social perception of faces.

The neuropeptide oxytocin plays a prominent role in social and emotional cognition. Findings suggest that intranasal oxytocin administration facilitates emotion recognition in humans, but individual and contextual differences may have moderating effects. A major caveat in this line of work is its predominant focus on young males, which limits current knowledge and generalizability across gender. To uncover potential gender effects, the present study included 32 men (mean age 45.78, sd. 22.87) and 39 women (mean 47.87, sd. 22.59). Utilizing a randomized, double-blind, placebo-controlled, within-subjects design, participants self-administered a single-dose of 40 IUs intranasal oxytocin 40 minutes prior to completion of a dynamic emotion recognition task in the MRI scanning. The task paradigm used positive and negative stimuli from the Geneva Multimodal Emotion Portrayals Core Set. Preliminary analyses show that oxytocin induced dorsomedial prefrontal cortex (dmPFC) activity reductions during exposure to negative (relative to positive) stimuli in women, while dmPCF activity was increased under this condition in men. We observed no effect of sex in the behavioral data, however, the results show a similar trend as in brain data. We speculate that the effects of oxytocin on brain activity during emotion recognition may be related to emotion-regulatory and mentalization processes. The observed gender-differential modulatory role of oxytocin raises concern of a bias in the previous oxytocin literature on emotion recognition and associated brain activity by neglecting women in the examination. Next, we will determine the role of age effects on gender-bytreatment interactions, as well as consider modality of the emotion stimulus presentation.  

This study presents findings about the effectiveness of two computerized training-programs for emotion recognition accuracy that were evaluated in a double-blind randomized controlled study with repeated measures design. Both trainings are effective in training emotion recognition accuracy. The trainings and results are presented in detail and practical implications are discussed.