Faces retain attention

Age-Group Differences in Interference from Young and Older Emotional Faces

Human attention is selective, focusing on some aspects of events at the expense of others. In particular, angry faces engage attention. Most studies have used pictures of young faces, even when comparing young and older age groups. Two experiments asked (1) whether task-irrelevant faces of young and older individuals with happy, angry, and neutral expressions disrupt performance on a face-unrelated task, (2) whether interference varies for faces of different ages and different facial expressions, and (3) whether young and older adults differ in this regard. Participants gave speeded responses on a number task while irrelevant faces appeared in the background. Both age groups were more distracted by own than other-age faces. In addition, young participants' responses were slower for angry than happy faces, whereas older participants' responses were slower for happy than angry faces. Factors underlying age-group differences in interference from emotional faces of different ages are discussed.

The wide window of face detection

Faces are detected more rapidly than other objects in visual scenes and search arrays, but the cause for this face advantage has been contested. In the present study, we found that under conditions of spatial uncertainty, faces were easier to detect than control targets (dog faces, clocks and cars) even in the absence of surrounding stimuli, making an explanation based only on low-level differences unlikely. This advantage improved with eccentricity in the visual field, enabling face detection in wider visual windows, and pointing to selective sparing of face detection at greater eccentricities. This face advantage might be due to perceptual factors favoring face detection. In addition, the relative face advantage is greater under flanked than non-flanked conditions, suggesting an additional, possibly attention-related benefit enabling face detection in groups of distracters.

When attractiveness demands longer looks: the effects of situation and gender

We investigated how aesthetics guides our exploration of the environment. We embedded attractive and nonattractive faces into complex, real-world scenes and measured eye movements during scene viewing. We examined whether attractive faces would elicit longer looks, which would suggest that the aesthetic response orients people toward the rewarding and pleasing aspects of the environment. Experiment 1 showed that mean fixation, mean first fixation, and total fixation durations were longer to attractive faces, and fixations were longest to female faces and by female perceivers. In Experiment 2, we examined whether these effects of attractiveness are sensitive to situational factors. When perceivers were subjected to a threat or social approach manipulation prior to viewing the scenes, we confirmed specific hypotheses concerning the two manipulations. In accordance with the hypothesis that males have higher aggression potential than females, there were no differences in fixation durations between attractive and nonattractive male faces in the threat condition. On the other hand, in the social approach condition, both female and male attractive faces received longer looks. These results suggest that the aesthetic response orients people not only to the pleasing aspects of their environment, but also to those features that are adaptively relevant.

Depressive symptoms in early pregnancy disrupt attentional processing of infant emotion

BACKGROUND

Growing evidence suggests that perinatal depression is associated with disrupted mother-infant interactions and poor infant outcomes. Antenatal depression may play a key role in this cycle by disrupting the development of a maternal response to infant stimuli. The current study therefore investigated the impact of depressive symptoms on the basic cognitive processing of infant stimuli at the beginning of pregnancy.

METHOD

A total of 101 women were recruited by community midwives and tested at an average gestation of 11 weeks. An established computerized paradigm measured women's ability to disengage attention from infant and adult faces displaying negative positive and neutral emotions. Depressive symptoms were measured using a computerized interview (the Clinical Interview Schedule).

RESULTS

The effect of infant emotion on women's ability to disengage from infant faces was found to be influenced by depressive symptoms. Non-depressed pregnant women took longer to disengage attention from distressed compared with non-distressed infant faces. This bias was not, however, seen in women experiencing depressive symptoms. There was a difference of -53 (s.d.=0.7) ms (95% confidence interval -90 to -14, p=0.007) between those with and without depressive symptoms in this measure of attentional bias towards distressed infant faces.

CONCLUSIONS

Our results suggest that depressive symptoms are already associated with differential attentional processing of infant emotion at the very beginning of childbearing. The findings have potential implications for our understanding of the impact of depressive symptoms during pregnancy on the developing mother-infant relationship.

Top-down and bottom-up modulation in processing bimodal face/voice stimuli

Background

Processing of multimodal information is a critical capacity of the human brain, with classic studies showing bimodal stimulation either facilitating or interfering in perceptual processing. Comparing activity to congruent and incongruent bimodal stimuli can reveal sensory dominance in particular cognitive tasks.

Results

We investigated audiovisual interactions driven by stimulus properties (bottom-up influences) or by task (top-down influences) on congruent and incongruent simultaneously presented faces and voices while ERPs were recorded. Subjects performed gender categorisation, directing attention either to faces or to voices and also judged whether the face/voice stimuli were congruent in terms of gender. Behaviourally, the unattended modality affected processing in the attended modality: the disruption was greater for attended voices. ERPs revealed top-down modulations of early brain processing (30-100 ms) over unisensory cortices. No effects were found on N170 or VPP, but from 180-230 ms larger right frontal activity was seen for incongruent than congruent stimuli.

Conclusions

Our data demonstrates that in a gender categorisation task the processing of faces dominate over the processing of voices. Brain activity showed different modulation by top-down and bottom-up information. Top-down influences modulated early brain activity whereas bottom-up interactions occurred relatively late.

Gaze Shifts Do Not Affect Preference Judgments of Graphic Patterns

The gaze cascade hypothesis argues that orienting behavior reflected in gaze shift plays an important role in preference formation for an object. Gazing at an object serves as reinforcement, by which the likelihood of gazing at that object again is increased. Evidence for this hypothesis has been obtained mainly from experiments in which people compare two facial stimuli for attractiveness. Two experiments were conducted to examine whether the gaze cascade effect occurs in preference judgments of novel graphic patterns. In Exp. 1, eye movements were tracked during three types of comparison tasks in which participants decided which one of two graphic patterns was more attractive, less attractive, or subjectively brighter. In Exp. 2, stimulus duration (900 or 300 msec.) and gaze shift (with or without) were manipulated. None of the results supported the hypothesis that gaze shifts would affect preference formation. Instead, the mere exposure effect was supported — stimuli that were viewed longer were preferred to those viewed for less time, regardless of gaze shift.

Resource Dependent Effects During Sex Categorization

The limited capacity of face perception resources in the left cerebral hemisphere was examined using a sex categorization task. One study tested the hypothesis that sex categorization is impeded whenever feature extraction resources in the left hemisphere are simultaneously being utilized by another task. This hypothesis was tested by presenting prime faces for either 32 ms or 320 ms to either the left or right visual-field just before centrally presented target faces were categorized by sex. Results showed that sex categorization was slower after prime faces were presented for 32 ms in the right visual-field compared to the left visual-field. This difference was not found after the 320 ms prime length. The results are interpreted in the context of a neurocognitive model of social perception and suggest that efficient sex categorization depends, in part, on the availability of facial feature extraction resources in the left hemisphere.

Attention capture by faces

We report three experiments that investigate whether faces are capable of capturing attention when in competition with other non-face objects. In Experiment 1a participants took longer to decide that an array of objects contained a butterfly target when a face appeared as one of the distracting items than when the face did not appear in the array. This irrelevant face effect was eliminated when the items in the arrays were inverted in Experiment 1b ruling out an explanation based on some low-level image-based properties of the faces. Experiment 2 replicated and extended the results of Experiment 1a. Irrelevant faces once again interfered with search for butterflies but, when the roles of faces and butterflies were reversed, irrelevant butterflies no longer interfered with search for faces. This suggests that the irrelevant face effect is unlikely to have been caused by the relative novelty of the faces or arises because butterflies and faces were the only animate items in the arrays. We conclude that these experiments offer evidence of a stimulus-driven capture of attention by faces.

Selective effects of cholinergic modulation on task performance during selective attention

The cholinergic neurotransmitter system is critically linked to cognitive functions including attention. The current studies were designed to evaluate the effect of a cholinergic agonist and an antagonist on performance during a selective visual attention task where the inherent salience of attended/unattended stimuli was modulated. Two randomized, placebo-controlled, crossover studies were performed, one (n=9) with the anticholinesterase physostigmine (1.0 mg/h), and the other (n=30) with the anticholinergic scopolamine (0.4 mc/kg). During the task, two double-exposure pictures of faces and houses were presented side by side. Subjects were cued to attend to either the face or the house component of the stimuli, and were instructed to perform a matching task with the two exemplars from the attended category. The cue changed every 4-7 trials to instruct subjects to shift attention from one stimulus component to the other. During placebo in both studies, reaction time (RT) associated with the first trial following a cued shift in attention was longer than RT associated with later trials (p<0.05); RT also was significantly longer when attending to houses than to faces (p<0.05). Physostigmine decreased RT relative to placebo preferentially during trials greater than one (p<0.05), with no change during trial one; and decreased RT preferentially during the attention to houses condition (p<0.05) vs attention to faces. Scopolamine increased RT relative to placebo selectively during trials greater than one (p<0.05), and preferentially increased RT during the attention to faces condition (p<0.05). The results suggest that enhancement or impairment of cholinergic activity preferentially influences the maintenance of selective attention (ie trials greater than 1). Moreover, effects of cholinergic manipulation depend on the selective attention condition (ie faces vs houses), which may suggest that cholinergic activity interacts with stimulus salience. The findings are discussed within the context of the role of acetylcholine both in stimulus processing and stimulus salience, and in establishing attention biases through top-down and bottom-up mechanisms of attention.

Evaluating the influence of the 'unity assumption' on the temporal perception of realistic audiovisual stimuli

Vatakis, A. and Spence, C. (in press) [Crossmodal binding: Evaluating the 'unity assumption' using audiovisual speech stimuli. Perception &Psychophysics] recently demonstrated that when two briefly presented speech signals (one auditory and the other visual) refer to the same audiovisual speech event, people find it harder to judge their temporal order than when they refer to different speech events. Vatakis and Spence argued that the 'unity assumption' facilitated crossmodal binding on the former (matching) trials by means of a process of temporal ventriloquism. In the present study, we investigated whether the 'unity assumption' would also affect the binding of non-speech stimuli (video clips of object action or musical notes). The auditory and visual stimuli were presented at a range of stimulus onset asynchronies (SOAs) using the method of constant stimuli. Participants made unspeeded temporal order judgments (TOJs) regarding which modality stream had been presented first. The auditory and visual musical and object action stimuli were either matched (e.g., the sight of a note being played on a piano together with the corresponding sound) or else mismatched (e.g., the sight of a note being played on a piano together with the sound of a guitar string being plucked). However, in contrast to the results of Vatakis and Spence's recent speech study, no significant difference in the accuracy of temporal discrimination performance for the matched versus mismatched video clips was observed. Reasons for this discrepancy are discussed.

Self-consciousness in non-communicative patients

The clinical and para-clinical examination of residual self-consciousness in non-communicative severely brain damaged patients (i.e., coma, vegetative state and minimally conscious state) remains exceptionally challenging. Passive presentation of the patient's own name and own face are known to be effective attention-grabbing stimuli when clinically assessing consciousness at the patient's bedside. Event-related potential and functional neuroimaging studies using such self-referential stimuli are currently being used to disentangle the cognitive hierarchy of self-processing. We here review neuropsychological, neuropathological, electrophysiological and neuroimaging studies using the own name and own face paradigm obtained in conscious waking, sleep, pharmacological coma, pathological coma and related disorders of consciousness. Based on these results we discuss what we currently do and do not know about the functional significance of the neural network involved in "automatic" and "conscious" self-referential processing.