Visual attributes of subliminal priming images impact conscious perception of facial expressions

We investigated, in young healthy participants, how the affective content of subliminally presented priming images and their specific visual attributes impacted conscious perception of facial expressions. The priming images were broadly categorized as aggressive, pleasant, or neutral and further subcategorized by the presence of a face and by the centricity (egocentric or allocentric vantage-point) of the image content. Participants responded to the emotion portrayed in a pixelated target-face by indicating via key-press if the expression was angry or neutral. Response time to the neutral target face was significantly slower when preceded by face primes, compared to non-face primes (p < 0.05, Bonferroni corrected). In contrast, faster RTs were observed when angry target faces were preceded by face compared to non-face primes. In addition, participants’ performance was worse when a priming image contained an egocentric face compared to when it contained either an allocentric face or an egocentric non-face. The results suggest a significant impact of the visual features of the priming image on conscious perception of face expression.Published versio

The emotional valence of subliminal priming effects perception of facial expressions

We investigated, in young healthy subjects, how the affective content of subliminally presented priming images and their specific visual attributes impacted conscious perception of facial expressions. The priming images were broadly categorised as aggressive, pleasant, or neutral and further subcategorised by the presence of a face and by the centricity (egocentric or allocentric vantage-point) of the image content. Subjects responded to the emotion portrayed in a pixelated target-face by indicating via key-press if the expression was angry or neutral. Priming images containing a face compared to those not containing a face significantly impaired performance on neutral or angry targetface evaluation. Recognition of angry target-face expressions was selectively impaired by pleasant prime images which contained a face. For egocentric primes, recognition of neutral target-face expressions was significantly better than of angry expressions. Our results suggest that, first, the affective primacy hypothesis which predicts that affective information can be accessed automatically, preceding conscious cognition, holds true in subliminal priming only when the priming image contains a face. Second, egocentric primes interfere with the perception of angry target-face expressions suggesting that this vantage-point, directly relevant to the viewer, perhaps engages processes involved in action preparation which may weaken the priority of affect processing.Accepted manuscrip

Raising the alarm: Individual differences in the perceptual awareness of masked facial expressions.

A theoretical concern in addressing the unconscious perception of emotion is the extent to which participants can access experiential properties of masked facial stimuli. Performance on a two alternative forced choice (2AFC) task as a measure of objective awareness was compared with a new measure developed to access experiential phenomena of the target-mask transition, the perceptual contrast-change sensitivity (PCCS) measure in a backward-masking paradigm with angry, happy and neutral facial expressions. Whilst 2AFC performance indicated that the targets were successfully masked, PCCS values were significantly higher in the happy-neutral face condition than in the angry-neutral face and the neutral-neutral face conditions (Experiment 1). Furthermore, objective measures of awareness were more readily displayed by individuals with high trait anxiety, whereas individuals with low trait anxiety showed greater access to the experiential quality of happy faces (Experiment 2). These findings provide important insights into the methodological considerations involved in the study of non-conscious processing of emotions, both with respect to individual differences in anxiety and the extent to which certain expressions can be successfully masked relative to others. Furthermore, our results may be informative to work investigating the neural correlates of conscious versus unconscious perception of emotion

Unconscious Processing of Facial Emotional Valence Relation: Behavioral Evidence of Integration between Subliminally Perceived Stimuli

Although a few studies have investigated the integration between some types of unconscious stimuli, no research has yet explored the integration between unconscious emotional stimuli. This study was designed to provide behavioral evidence for the integration between unconsciously perceived emotional faces (same or different valence relation) using a modified priming paradigm. In two experiments, participants were asked to decide whether two faces in the target, which followed two subliminally presented faces of same or different emotional expressions, were of the same or different emotional valence. The interstimulus interval (ISI) between the prime and the target was manipulated (0, 53, 163 ms). In Experiment 1, prime visibility was assessed post-experiment. In Experiment 2, it was assessed on each trial. Interestingly, in both experiments, unconsciously processed valence relation of the two faces in the prime generated a negative priming effect in the response to the supraliminally presented target, independent of the length of ISI. Further analyses suggested that the negative priming was probably caused by a motor response incongruent relation between the subliminally perceived prime and the supraliminally perceived target. The visual feature incongruent relation across the prime and target was not found to play a role in the negative priming. Because the negative priming was found at short ISI, an attention mechanism as well as a motor inhibition mechanism were proposed in the generation of the negative priming effect. Overall, this study indicated that the subliminal valence relation was processed, and that integration between different unconsciously perceived stimuli could occur

Effects of Unconscious Processing on Implicit Memory for Fearful Faces

Emotional stimuli can be processed even when participants perceive them without conscious awareness, but the extent to which unconsciously processed emotional stimuli influence implicit memory after short and long delays is not fully understood. We addressed this issue by measuring a subliminal affective priming effect in Experiment 1 and a long-term priming effect in Experiment 2. In Experiment 1, a flashed fearful or neutral face masked by a scrambled face was presented three times, then a target face (either fearful or neutral) was presented and participants were asked to make a fearful/neutral judgment. We found that, relative to a neutral prime face (neutral–fear face), a fearful prime face speeded up participants' reaction to a fearful target (fear–fear face), when they were not aware of the masked prime face. But this response pattern did not apply to the neutral target. In Experiment 2, participants were first presented with a masked faces six times during encoding. Three minutes later, they were asked to make a fearful/neutral judgment for the same face with congruent expression, the same face with incongruent expression or a new face. Participants showed a significant priming effect for the fearful faces but not for the neutral faces, regardless of their awareness of the masked faces during encoding. These results provided evidence that unconsciously processed stimuli could enhance emotional memory after both short and long delays. It indicates that emotion can enhance memory processing whether the stimuli are encoded consciously or unconsciously

Processamento da confiabilidade em caras: o papel das diferenças individuais nos estilos de vinculação

Research suggests that the presence of a human face elicits automatic appraisals of its trustworthiness. To completely understand trust-based interactions, research must consider not only the characteristics of the person that make him or her trustworthy but also the observer effects that contribute to individual variation in such judgments. Based on the assumption that different attachment styles can influence attention mechanisms and information processing, the main goal of the current dissertation was to investigate the impact of attachment representations on the processing of facial cues that resemble (un)trustworthiness. Using a multi-method approach, this thesis investigated the novel issue of whether and how attachment styles are related to interpretational (Study 1) and/or attentional biases of facial (un)trustworthiness (Study 2 and 3). In Study 1, using a sample of 179 participants, we asked the simple but fundamental question of whether individuals with different attachment styles differ in their conscious appraisal of facial trustworthiness. Given that recent studies have shown that individuals high in trait anxiety are also biased to interpret ambiguous stimuli in a threatening way, we also explored whether individuals level of (trait and state) anxiety would also impact judgments of trustworthiness. We found that both anxiosuly-attached and highly trait-anxious individuals were more sensitive to changes in untrustworthy than trustworthy faces, judging unfamiliar untrustworthy and neutral-looking faces as more untrustworthy than less anxious individuals. In study 2, using one of the most widely used tasks in attention bias research, we aimed to investigate the extent to which an individual’s attachment style is associated with selective attention to un(trustworthy) faces. Specifically, our second study introduced an adapted dot-probe design to more clearly investigate what specific selective attention processes (orienting or disengaging) is responsible for a potential attentional bias in insecure individuals. With a sample of 167 participants, our findings suggested that both individuals who scored high on anxious-attachment and trait-anxiety have a difficulty disengaging their attention from untrustworthy faces. Finally, in our third study, we employed another widely used electroencephalography paradigm (the oddball task) to examine the neural correlates of facial untrustworthiness processing and shed light on the temporal characteristics of a possible processing bias toward untrustworthy faces. With a sample of 56 participants, our results revealed greater P3 (350-600 ms) amplitude in response to untrustworthy than neutral faces, suggesting that untrustworthy faces are more salient to all individuals. To our knowledge, the present investigation is the first one to assess whether and how attachment styles are associated with the processing of facial cues that resemble (un)trustworthiness.Investigações sugerem que a presença de uma cara humana provoca uma avaliação automática do seu nível de confiabilidade. Para compreender completamente as interações baseadas na confiança, a investigação deve considerar, para além das características do parceiro que o/a tornam confiável, os efeitos do observador que contribuem para a variação individual nesses julgamentos. Tendo como base a ideia de que diferentes tipos de vinculação podem influenciar os mecanismos atencionais e o processamento de informação, a presente tese teve como principal objetivo investigar o impacto do estilo de vinculação no processamento da confiabilidade em caras. Com o recurso a diferentes métodos de investigação, o presente trabalho investigou o tópico inovador de uma potencial correlação entre o tipo de vinculação e a presença de um viés interpretativo (Estudo 1) e/ou atencional (Estudos 2 e 3) em relação a caras que variam na sua confiabilidade. O Estudo 1, com uma amostra de 179 participantes, teve como base a simples, mas pertinente, questão de saber se indivíduos com estilos de vinculação diferentes diferem na sua avaliação consciente da confiabilidade com base na aparência facial. Dado que estudos recentes demonstraram que indivíduos com graus elevados de ansiedade-traço interpretam estímulos ambíguos como ameaçadores, o primeiro estudo também explorou se o grau de ansiedade (traço e estado) impacta avaliações de confiabilidade. Os resultados sugeriram que tanto indivíduos com uma vinculação ansiosa como indivíduos com graus elevados de ansiedade traço são mais sensíveis a mudanças em faces de baixa, comparativamente a alta, confiabilidade, julgando caras que parecem pouco confiáveis e neutras como menos confiáveis, do que indivíduos menos ansiosos. O Estudo 2, recorrendo a uma das tarefas mais usadas na investigação sobre enviesamentos atencionais, teve como objetivo investigar o grau de associação entre o estilo de vinculação e a atenção seletiva para caras que variam em confiabilidade. Especificamente, o segundo estudo introduziu uma adaptação no design da tarefa de dot-probe, com o intuito de investigar de forma mais precisa quais os processos responsáveis por um potencial viés atencional em indivíduos com uma vinculação insegura. Utilizando uma amostra de 167 participantes, os resultados sugeriram que ambos os indivíduos que pontuaram alto no estilo de vinculação insegura e na ansiedade-traço demonstram dificuldade em desviar a sua atenção de caras com baixa confiabilidade percebida. Por fim, no terceiro estudo, aplicamos uma tarefa amplamente usada em estudos eletroencefalográficos (a tarefa de oddball), com o intuito de avaliar os correlatos neuronais do processamento de confiabilidade em caras e identificar as características temporais de um possível enviesamento em relação a faces pouco confiáveis. Recorrendo a uma amostra de 56 participantes, os resultados revelaram uma maior amplitude na P3 em resposta a caras de baixa confiabilidade comparativamente a caras neutras, sugerindo que estas faces parecem ter um elevado grau de saliência para todos os indivíduos. Tanto quanto sabemos, a presente investigação é a primeira a avaliar se e como é que os estilos de vinculação se associam ao processamento de pistas faciais que aparentam baixa ou alta confiabilidade.Programa Doutoral em Psicologi

Affect, Risk-Taking, and Financial Decisions: Investigating the Psychological and Neural Mechanisms By Which Conscious and Unconscious Affective Processes Influence Decisions.

This dissertation consists of three studies designed to elucidate the psychological and neural mechanisms by which affect influences risk-taking in financial decisions. The mechanisms underlying conscious and unconscious affective processes are investigated using multiple methods and approaches from personality and social psychology, cognitive psychology, and affective neuroscience. Results show that affect plays a crucial role in financial decisions and that there may be two interactive systems by which affect influences decisions. The unconscious system exerts valence-based effects on decisions, responds preferentially to implicit measures and implicitly processed affective cues, and is likely mediated predominantly by subcortical brain structures. The conscious system exerts emotion-specific effects on decisions, responds preferentially to explicit measures and mood induction methods that result in more lasting changes in affect, and is likely mediated predominantly by cortical brain structures. Study 1 uses fMRI to examine the effects of subliminally and supraliminally presented positive and negative affective primes on financial risk-taking and neural markers of anticipatory arousal. Results show that happy facial expressions increase financial risk-taking and activation in the nucleus accumbens, an effect that was significantly stronger in unconscious than conscious conditions. Study 2 tests valence-based and emotion-specific theories of risk by using affective primes of the same valence, fearful and angry faces, presented at 3 stimulus durations (subliminal, short, long) and examining their effect on financial risk-taking. Results show that both fearful and angry faces reduce financial risk-taking after short stimulus presentations, but only fearful faces reduce financial risk-taking after long stimulus presentations. Study 3 investigates the role of individual differences in affect on financial risk-taking using implicit versus explicit measures of affect. Individuals high in negative affect as measured through two versions of a mood implicit association test made more safe bond choices on an investment task whereas explicit measures of individual differences in affect had no effect on financial risk-taking. Taken together, these findings provide support for the idea of a dual process model of risk.Ph.D.PsychologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/78872/1/halljl_1.pd

Are visual threats prioritized without awareness? A critical review and meta analysis involving 3 behavioral paradigms and 2696 observers

Given capacity limits, only a subset of stimuli 1 give rise to a conscious percept. Neurocognitive models suggest that humans have evolved mechanisms that operate without awareness and prioritize threatening stimuli over neutral stimuli in subsequent perception. In this meta analysis, we review evidence for this ‘standard hypothesis’ emanating from three widely used, but rather different experimental paradigms that have been used to manipulate awareness. We found a small pooled threat-bias effect in the masked visual probe paradigm, a medium effect in the binocular rivalry paradigm and highly inconsistent effects in the breaking continuous flash suppression paradigm. Substantial heterogeneity was explained by the stimulus type: the only threat stimuli that were robustly prioritized across all three paradigms were fearful faces. Meta regression revealed that anxiety may modulate threat biases, but only under specific presentation conditions. We also found that insufficiently rigorous awareness measures, inadequate control of response biases and low level confounds may undermine claims of genuine unconscious threat processing. Considering the data together, we suggest that uncritical acceptance of the standard hypothesis is premature: current behavioral evidence for threat-sensitive visual processing that operates without awareness is weak

Contextual information resolves uncertainty about ambiguous facial emotions: Behavioral and magnetoencephalographic correlates

We are grateful to Karin Wilken for her assistance in data collection.Environmental conditions bias our perception of other peoples’ facial emotions. This becomes quite relevant in potentially threatening situations, when a fellow’s facial expression might indicate potential danger. The present study tested the prediction that a threatening environment biases the recognition of facial emotions. To this end, low- and medium-expressive happy and fearful faces (morphed to 10%, 20%, 30%, or 40% emotional) were presented within a context of instructed threat-of-shock or safety. Self-reported data revealed that instructed threat led to a biased recognition of fearful, but not happy facial expressions. Magnetoencephalographic correlates revealed spatio-temporal clusters of neural network activity associated with emotion recognition and contextual threat/safety in early to mid-latency time intervals in the left parietal cortex, bilateral prefrontal cortex, and the left temporal pole regions. Early parietal activity revealed a double dissociation of face–context information as a function of the expressive level of facial emotions: When facial expressions were difficult to recognize (lowexpressive), contextual threat enhanced fear processing and contextual safety enhanced processing of subtle happy faces. However, for rather easily recognizable faces (medium-expressive) the left hemisphere (parietal cortex, PFC, and temporal pole) showed enhanced activity to happy faces during contextual threat and fearful faces during safety. Thus, contextual settings reduce the salience threshold and boost early face processing of lowexpressive congruent facial emotions, whereas face-context incongruity or mismatch effects drive neural activity of easier recognizable facial emotions. These results elucidate how environmental settings help recognize facial emotions, and the brain mechanisms underlying the recognition of subtle nuances of fear.German Research Foundation (DFG) BU 3255/1-1 Ju2/024/15 SF58C0

Decreased Pain Perception by Unconscious Emotional Pictures

Pain perception arises from a complex interaction between a nociceptive stimulus and different emotional and cognitive factors, which appear to be mediated by both automatic and controlled systems. Previous evidence has shown that whereas conscious processing of unpleasant stimuli enhances pain perception, emotional influences on pain under unaware conditions are much less known. The aim of the present study was to investigate the modulation of pain perception by unconscious emotional pictures through an emotional masking paradigm. Two kinds of both somatosensory (painful and non-painful) and emotional stimulation (negative and neutral pictures) were employed. Fifty pain-free participants were asked to rate the perception of pain they were feeling in response to laser-induced somatosensory stimuli as faster as they can. Data from pain intensity and reaction times were measured. Statistical analyses revealed a significant effect for the interaction between pain and emotional stimulation, but surprisingly this relationship was opposite to expected. In particular, lower pain intensity scores and longer reaction times were found in response to negative images being strengthened this effect for painful stimulation. Present findings suggest a clear pain perception modulation by unconscious emotional contexts. Attentional capture mechanisms triggered by unaware negative stimulation could explain this phenomenon leading to a withdrawal of processing resources from pain