Working memory for gaze benefits from the face context

Retaining gaze in working memory (WM) is essential for successfully navigating through the social world. In the current study, we investigated how WM stores gaze direction by focusing on the role of face context in gaze WM. To address this question, we propose two competing hypotheses. The independence hypothesis predicts that eye gaze is stored independently and is not susceptible to the influence of the surrounding face context. Conversely, the embedding hypothesis claims that gaze WM involves face context and that disruption of holistic face processing would also impair memory for embedded gaze. In three experiments, we adopted different manipulations to disrupt holistic face processing and compared WM performance for gaze within and without face context. In Experiments 1 and 2, we tested WM for gaze direction with schematic upright or inverted faces. We found better performance for gaze within upright faces (vs. inverted faces) by increasing the probability of being remembered. In Experiment 3, we replaced schematic faces with photographic faces, and disrupted holistic processing by using scrambled faces. Results replicated our previous findings, showing that photographic gaze within intact faces was better remembered than gaze presented alone or gaze within scrambled faces. These findings indicate that gaze memory is face-dependent and support the embedding hypothesis.

Preverbal infants tune manual choices on subliminal affective information

Human behaviour is often shaped by unconscious emotional cues. From early on, infants are able to process emotional signals even if presented subliminally; however, whether subliminal emotional expressions are capable to affect infants' behaviour remains unknown. The current study aimed to fill this gap, recording 8-10-month-old infants' looking time and manual choice toward two objects previously associated to subliminal emotional faces. Results demonstrated that infants' manual choice, but not looking time, was guided by the previously presented subliminal emotional signal, as infants preferred to choose the object associated to the happy face. Overall, our findings show that preverbal infants tune their behaviour based on affective information, which drives them towards or away from previous encounters, even outside conscious awareness.

Memory for facial expressions on the autism spectrum: The influence of gaze direction and type of expression

Face memory research in autism has largely neglected memory for facial expressions, in favor of memory for identity. This study in three experiments examined the role of gaze direction and type of expression on memory for facial expressions in relation to the autism spectrum. In the learning phase, four combinations of facial expressions (joy/anger) and gaze direction (toward/away), displayed by 16 different identities, were presented. In a subsequent surprise test the same identities were presented displaying neutral expressions, and the expression of each identity had to be recalled. In Experiment 1, typically-developed (TD) individuals with low and high Autism Quotient (AQ) scores were tested with three repetitions of each emotion/gaze combination, which did not produce any modulations. In Experiment 2, another group of TD individuals with low and high AQ scores were tested with eight repetitions, resulting in a "happy advantage" and a "direct gaze advantage", but no interactions. In Experiment 3, individuals with high-functioning autism (HFA) and a matched TD group were tested using eight repetitions. The HFA group revealed no emotion or gaze effects, while the matched TD group showed both a happy and a direct gaze advantage, and again no interaction. The results suggest that in autistic individuals the memory for facial expressions is intact, but is not modulated by the person's expression type and gaze direction. We discuss whether anomalous implicit learning of facial cues could have contributed to these findings, its relevance for social intuition, and its possible contribution to social deficits in autism. LAY SUMMARY: It has often been found that memory for someone's face (facial identity) is less good in autism. However, it is not yet known whether memory for someone's facial expression is also less good in autism. In this study, the memory for expressions of joy and anger was investigated in typically-developed (TD) individuals who possessed either few or many autistic-like traits (Experiments 1 and 2), and in individuals with high-functioning autism (Experiment 3). The gaze direction was also varied (directed either toward, or away from, the observer). We found that TD individuals best remembered expressions of joy, and remembered expressions of both joy and anger better when the gaze was directed at them. These effects did not depend on the extent to which they possessed autistic-like traits. Autistic participants remembered the facial expression of a previously encountered person as good as TD participants did. However, in contrast to the TD participants, the memory of autistic participants was not influenced by the expression type and gaze direction of the previously encountered persons. We discuss whether this may lead to difficulties in the development of social intuition, which in turn could give rise to difficulties in social interaction that are characteristic for autism.

Memory updating through aging: different patterns for socially meaningful (and not) stimuli

BACKGROUND

Updating is a crucial function responsible of working memory integrity, allowing relevant information to be active and inhibiting irrelevant one; updating has been studied mainly with verbal stimuli, less with faces, stimuli with high adaptive value and social meaning.

AIM

Our aim was to test age-related differences in updating for different stimuli in three different age groups: young adults (range 20-30 years), young-old (range 60-75 years) and older-old participants (range 77-87 years).

METHODS

To this end, we administered control measures (i.e., vocabulary and visuospatial tasks), span tasks (forward, backward) and two updating tasks: one with no socially relevant material (i.e., letters) and another one with socially relevant material (i.e., human faces, where, in particular, the combination between facial expression and gaze direction was manipulated). In both tasks we collected response times (RTs) at different steps of an updating task (i.e., encoding, maintaining, and updating goal-relevant information).

RESULTS AND DISCUSSION

We found that age linearly produces an increase in processing speed regardless the stimulus considered, either letter or human face. However, with face stimuli, the magnitude of the difference is greater for the letter updating task, than for the face updating task. In turn, the results claim for a stimulus-specific updating process as the age-related decline is less pronounced when socially meaningful stimuli are involved than when no socially meaningful ones are.

Platelet MAO activity and COMT Val158Met genotype interaction predicts visual working memory updating efficiency

The exact mechanism how serotonergic and dopaminergic systems relate to one another in working memory (WM) updating is unknown. Platelet monoamine oxidase (MAO) has been used as a marker for central serotonergic capacity, and catechol-O-methyltransferase (COMT) as a marker for central dopaminergic capacity. This study aimed to describe the interaction of platelet MAO activity and COMT Val158Met genotype in visual working memory updating: the ability to replace old information with new within hundreds of milliseconds. Previous studies suggest that platelet MAO activity and COMT Val158Met genotype could have an interaction effect on working memory. However, there are no studies that have directly examined the interaction of these biomarkers in WM updating. We used a 2-back updating task with facial expressions and defined updating efficiency as response times for correct responses. 455 subjects from a population representative sample were included. Mixed models were used for data analysis with an aim to study the interaction of COMT Val158Met genotype (Val/Val, Val/Met and Met/Met) and the level of MAO activity (high vs low). Education, IQ, sex, simple reaction times, and overall updating accuracy were included as covariates. We found that the effect of COMT Val158Met on updating efficiency depends on the level of platelet MAO activity. Low MAO in contrast to high MAO was associated with an increase in updating efficiency in Val/Met but a decrease in Met/Met. The results are discussed in the context of serotonin and dopamine functions in brain regions related to WM. The findings support the view that serotonin modulates dopaminergic activation in updating and contribute to understanding the role of serotonin in PFC, top-down inhibitory signals, and its interactions with dopamine in WM processes.

Updating facial emotional expressions in working memory: Differentiating trait anxiety and depressiveness

Individual differences in updating emotional facial expressions in working memory are not fully understood. Here we focused on the effects of high trait anxiety and high depressiveness in men and women on updating schematic emotional facial expressions (sad, angry, scheming, happy, neutral). A population representative sample of young adults was divided into four emotional disposition groups based on STAI-T and MADRS cut-offs: high anxiety (HA, n = 41), high depressiveness (HD, n = 31), high depressiveness & high anxiety (HAHD, n = 65) and control (CT, n = 155). Participants completed a 2-back task with schematic emotional faces, and valence/arousal ratings and verbal recognition tasks. A novel approach was used to separate encoding from retrieval. We found an interaction of emotional dispositions and emotional faces in updating accuracy. HD group made more errors than HA when encoding happy schematic faces. Other differences between emotional dispositions on updating measures were found but they were not specific to any emotional facial expression. Our findings suggest that there is a minor happy disadvantage in HD in contrast to HA which can be seen in lower accuracy for visual encoding of happy faces, but not in retrieval accuracy, the speed of updating, nor perception of emotional content in happy faces. These findings help to explain differences and similarities between high trait anxiety and high depressiveness in working memory and processing of facial expressions. The results are discussed in relation to prevalent theories of information processing in anxiety and depression.

How social exclusion modulates social information processing: A behavioural dissociation between facial expressions and gaze direction

Social exclusion is a painful experience that is felt as a threat to the human need to belong and can lead to increased aggressive and anti-social behaviours, and results in emotional and cognitive numbness. Excluded individuals also seem to show an automatic tuning to positivity: they tend to increase their selective attention towards social acceptance signals. Despite these effects known in the literature, the consequences of social exclusion on social information processing still need to be explored in depth. The aim of this study was to investigate the effects of social exclusion on processing two features that are strictly bound in the appraisal of the meaning of facial expressions: gaze direction and emotional expression. In two experiments (N = 60, N = 45), participants were asked to identify gaze direction or emotional expressions from facial stimuli, in which both these features were manipulated. They performed these tasks in a four-block crossed design after being socially included or excluded using the Cyberball game. Participants’ empathy and self-reported emotions were recorded using the Empathy Quotient (EQ) and PANAS questionnaires. The Need Threat Scale and three additional questions were also used as manipulation checks in the second experiment. In both experiments, excluded participants showed to be less accurate than included participants in gaze direction discrimination. Modulatory effects of direct gaze (Experiment 1) and sad expression (Experiment 2) on the effects of social exclusion were found on response times (RTs) in the emotion recognition task. Specific differences in the reaction to social exclusion between males and females were also found in Experiment 2: excluded male participants tended to be less accurate and faster than included male participants, while excluded females showed a more accurate and slower performance than included female participants. No influence of social exclusion on PANAS or EQ scores was found. Results are discussed in the context of the importance of identifying gaze direction in appraisal theories.

The nature and emotional valence of a prime influences the processing of emotional faces in adults and children

A large body of research has investigated both the emotional elaboration of facial stimuli in adults and the development of children’s recognition of emotional expressions. Yet, it is still not clear whether children’s ability to recognize an emotional face may be modulated by prior exposure to a different face, and whether an emotional expression may exert an effect on the processing of subsequently encountered facial emotional expressions. We tested in three experiments the recognition of happy and angry target faces preceded by neutral faces or objects (Experiment 1) and happy or angry faces (Experiment 2A and Experiment 2B) using an affective priming task in adults and 7- and 5-year-old children. Results showed a standard prime effect for neutral faces (Experiment 1) for all participants, and for happy faces in children (Experiment 2A) and adults (Experiment 2B). Otherwise, angry faces elicited negative priming effects in all participants (Experiment 2A). Overall, our findings showed that both prior exposure to a face per se and the emotional valence of the prime face have an impact on subsequent processing of facial emotional information. Implications for emotional processing are discussed.

Updating schematic emotional facial expressions in working memory: Response bias and sensitivity

It is unclear if positive, negative, or neutral emotional expressions have an advantage in short-term recognition. Moreover, it is unclear from previous studies of working memory for emotional faces whether effects of emotions comprise response bias or sensitivity. The aim of this study was to compare how schematic emotional expressions (sad, angry, scheming, happy, and neutral) are discriminated and recognized in an updating task (2-back recognition) in a representative sample of birth cohort of young adults. Schematic facial expressions allow control of identity processing, which is separate from expression processing, and have been used extensively in attention research but not much, until now, in working memory research. We found that expressions with a U-curved mouth (i.e., upwardly curved), namely happy and scheming expressions, favoured a bias towards recognition (i.e., towards indicating that the probe and the stimulus in working memory are the same). Other effects of emotional expression were considerably smaller (1-2% of the variance explained)) compared to a large proportion of variance that was explained by the physical similarity of items being compared. We suggest that the nature of the stimuli plays a role in this. The present application of signal detection methodology with emotional, schematic faces in a working memory procedure requiring fast comparisons helps to resolve important contradictions that have emerged in the emotional perception literature.