Conscious awareness is required for holistic face processing

Investigating the limits of unconscious processing is essential to understand the function of consciousness. Here, we explored whether holistic face processing, a mechanism believed to be important for face processing in general, can be accomplished unconsciously. Using a novel “eyes-face” stimulus we tested whether discrimination of pairs of eyes was influenced by the surrounding face context. While the eyes were fully visible, the faces that provided context could be rendered invisible through continuous flash suppression. Two experiments with three different sets of face stimuli and a subliminal learning procedure converged to show that invisible faces did not influence perception of visible eyes. In contrast, surrounding faces, when they were clearly visible, strongly influenced perception of the eyes. Thus, we conclude that conscious awareness might be a prerequisite for holistic face processing.     

Crucial information for efficient face searching by humans and Japanese macaques

Humans can efficiently detect a face among non-face objects, but few studies of this ability have been conducted in animals. Here, in Japanese macaques and humans, we examined visual searching for a face and explored what factors contribute to efficient facial information processing. Subjects were asked to search for an odd target among the different numbers of distracters. Faces of the subjects’ own species, the backs of the head of the subjects’ own species, faces of the subjects’ closely related species or race, and faces of species that are clearly different from the subjects’ own species were used as the target. Both the macaques and humans detected a face of their own species more efficiently than a face from a clearly different species. Similar efficient detections were confirmed for the faces of the subjects’ closely related species or race. These results suggest that conspecific faces and faces that share morphological similarity with conspecific faces can be detected efficiently among non-face objects by both humans and Japanese macaques. In another experiment, facial recognition efficiency was observed when the subjects searched for own-species faces that had lower-spatial-frequency components compared to faces with higher-spatial-frequency components. It seems reasonable that the ability to search efficiently for faces by using holistic face processing is derived from fundamental social cognition abilities that are broadly shared among species.     

自我与他人视角的动态信息加工：一项行为振荡研究

为了实现流畅的社会互动,个体需要同时加工自我与他人视角下的信息,并能有效地区分二者。然而个体对自我与他人视角下的信息存在共享神经表征,那么大脑是如何在同时完成自我与他人视角信息加工的前提下又不至于混淆二者的呢？本文通过创新性的、具有高时间分辨率的内隐视觉观点采择任务,发现对于自我视角和他人视角下的信息加工存在频率约为1 Hz的行为振荡现象,并且二者存在180°左右的相位差。这一结果说明在有他人在场的社会情景中,自我视角与他人视角下的信息加工是一种具有周期性的交替优势的过程。     

Perceptual awareness and categorical representation of faces: evidence from masked priming

How internal categories influence how we perceive the world is a fundamental question in cognitive sciences. Yet, the relation between perceptual awareness and perceptual categorization has remained largely uncovered so far. Here, we addressed this question by focusing on face perception during subliminal and conscious perception. We used morphed continua between two face identities and we assessed, through a masked priming paradigm, the perceptual processing of these morphed faces under subliminal and supraliminal conditions. We found that priming from subliminal faces followed linearly the information present in the primes, while priming from visible faces revealed a non-linear profile, indicating a categorical processing of face identities. Our results thus point to a special relation between perceptual awareness and categorical processing of faces, and support the dissociation between two modes of information processing: a subliminal mode involving analog treatment of stimuli information, and a supraliminal mode relying on discrete representation.     

Your own face is no more precious than others’: Evidence from the simultaneous–sequential paradigm

In the present study, we tested the dominant notion that the processing of familiar faces takes place in an automatic, capacity-unlimited manner. To do so, we had participants perform the task of detecting their own face among others’ nonfamiliar faces. Importantly, either all of the search stimuli were presented simultaneously or two different subsets of the stimuli were presented sequentially. The results showed that the search performance benefited from sequential presentation, indicating that detecting one’s own face depends on a capacity-limited process. A similar pattern of results was found when participants searched for someone else’s face, although there was a decline in the overall performance. These findings suggest that the processes of detecting familiar and unfamiliar faces suffer from the capacity limit of visual perception to similar extents, challenging the notion of the automaticity of familiar-face processing.     

Remembering the past and imagining the future in schizophrenia

It has been suggested that patients with schizophrenia experience a distorted sense of continuity of self across time. However, temporal aspects of self-processing have received little empirical attention in schizophrenia. In this study, the authors investigated schizophrenic patients' ability to generate specific mental images of their personal past and future. Results showed that patients recalled fewer specific past events than did healthy controls and were even more impaired in generating specific future events. These deficits were associated with positive symptoms but were not associated with negative symptoms or with performances on verbal fluency tasks. It is suggested that schizophrenic patients' failures to project themselves into specific past and future episodes might be related to difficulties in retrieving contextual details from memory, as well as disturbance of the sense of subjective time.     

Interaction of prime and target in the subliminal affective priming effect

It has been found that an emotional stimulus such as a facial expression presented subliminally can affect subsequent information processing and behavior, usually by shifting evaluation of a subsequent stimulus to a valence congruent with the previous stimulus. This phenomenon is called subliminal affective priming. The present study was conducted to replicate and expand previous findings by investigating interaction of primes and targets in the affective priming effect. Two conditions were used. Prime (subliminal presentation 35 msec.) of an angry face of a woman and a No Prime control condition. Just after presentation of the prime, an ambiguous angry face or an emotionally neutral face was presented above the threshold of awareness (500 msec.). 12 female undergraduate women judged categories of facial expressions (Anger, Neutral, or Happiness) for the target faces. Analysis indicated that the Anger primes significantly facilitated judgment of anger for the ambiguous angry faces; however, the priming effect of the Anger primes was not observed for neutral faces. Consequently, the present finding suggested that a subliminal affective priming effect should be more prominent when affective valence of primes and targets is congruent.     

Objects that induce face pareidolia are prioritized by the visual system

The human visual system has evolved specialized neural mechanisms to rapidly detect faces. Its broad tuning for facial features is thought to underlie the illusory perception of faces in inanimate objects, a phenomenon called face pareidolia. Recent studies on face pareidolia suggest that the mechanisms underlying face processing, at least at the early stages of visual encoding, may treat objects that resemble faces as real faces; prioritizing their detection. In our study, we used breaking continuous flash suppression (b-CFS) to examine whether the human visual system prioritizes the detection of objects that induce face pareidolia over stimuli matched for object content. Similar to previous b-CFS results using real face stimuli, we found that participants detected the objects with pareidolia faces faster than object-matched control stimuli. Given that face pareidolia has been more frequently reported amongst individuals prone to hallucinations, we also explored whether this rapid prioritization is intact in individuals with schizophrenia, and found evidence suggesting that it was. Our findings suggest that face pareidolia engages a broadly tuned mechanism that facilitates rapid face detection. This may involve the proposed fast subcortical pathway that operates outside of visual awareness.     

知觉场理论对面孔知觉年龄偏差效应的解释

使用融合面孔范式和倒置面孔范式来研究面孔知觉的年龄偏差效应,检验知觉场能否作为面孔整体加工的指标,并以此发展年龄偏差的整体加工解释。结果发现：（1）成人和儿童在加工正立面孔时的知觉场均大于加工倒置面孔时的知觉场;（2）在加工正立面孔时,成人加工本年龄面孔比加工他年龄面孔的知觉场更大。上述结果表明：（1）知觉场大小可以作为面孔整体加工的指标,且受面孔朝向的影响;（2）知觉场假设可以解释面孔的年龄偏差效应。     

知觉场理论对面孔知觉年龄偏差效应的解释

使用融合面孔范式和倒置面孔范式来研究面孔知觉的年龄偏差效应,检验知觉场能否作为面孔整体加工的指标,并以此发展年龄偏差的整体加工解释。结果发现：（1）成人和儿童在加工正立面孔时的知觉场均大于加工倒置面孔时的知觉场;（2）在加工正立面孔时,成人加工本年龄面孔比加工他年龄面孔的知觉场更大。上述结果表明：（1）知觉场大小可以作为面孔整体加工的指标,且受面孔朝向的影响;（2）知觉场假设可以解释面孔的年龄偏差效应。     

Holistic face encoding is modulated by perceived face race: Evidence from perceptual adaptation

Human expertise at processing faces relies on how facial features are encoded: as a whole template rather than as a sum of independent features. This holistic encoding is less prominent for other-race faces, possibly accounting for the difficulty one encounters in recognizing these faces (the ‘other-race effect’). Here, we tested the hypothesis that the magnitude of holistic face encoding can be modulated by racial categorization of the face. Caucasian participants performed a face-composite task with ‘racially-ambiguous’ face-stimuli (cross-race morphed faces, equally categorized as Asian or Caucasian faces in an independent task). The perceived race of the ambiguous faces was manipulated using adaptation. Experiment 1 showed that identical morphed face-stimuli were processed more holistically when perceived as ‘same-race’ than as ‘other-race’, i.e., following adaptation to ‘other-race’ versus ‘same-race’, respectively. Experiment 2 ascertained that the determining factor in the observed holistic processing modulation was the race of the racially-ambiguous face as perceived, rather than expected, by the participants, which supports the idea that the holistic processing of the face-stimuli was modulated by their race-categorization at the perceptual level.     

Biracial and monoracial infant own‐race face perception: an eye tracking study

We know that early experience plays a crucial role in the development of face processing, but we know little about how infants learn to distinguish faces from different races, especially for non‐Caucasian populations. Moreover, it is unknown whether differential processing of different race faces observed in typically studied monoracial infants extends to biracial infants as well. Thus, we investigated 3‐month‐old Caucasian, Asian and biracial (Caucasian‐Asian) infants’ ability to distinguish Caucasian and Asian faces. Infants completed two within‐subject, infant‐controlled habituation sequences and test trials as an eye tracker recorded looking times and scanning patterns. Examination of individual differences revealed significant positive correlations between own‐race novelty preference and scanning frequency between eye and mouth regions of own‐race habituation stimuli for Caucasian and Asian infants, suggesting that facility in own‐race face discrimination stems from active inspection of internal facial features in these groups. Biracial infants, however, showed the opposite effect: An ‘own‐race’ novelty preference was associated with reduced scanning between eye and mouth regions of ‘own‐race’ habituation stimuli, suggesting that biracial infants use a distinct approach to processing frequently encountered faces. Future directions for investigating face processing development in biracial populations are discussed. A video abstract of this article can be viewed at http://youtu.be/a_dDXfFuEfY     

Task‐irrelevant own‐race faces capture attention: Eye‐tracking evidence

To investigate attentional capture by face’s race, the current study recorded saccade latencies of eye movement measurements in an inhibition of return (IOR) task. Compared to Caucasian (other‐race) faces, Chinese (own‐race) faces elicited longer saccade latency. This phenomenon disappeared when faces were inverted. The results indicated that own‐race faces capture attention automatically with high‐level configural processing.     

不同愉悦度面孔阈下情绪启动效应:来自ERP的证据

采用事件相关电位技术,研究阈下情绪启动效应。实验中的因素是阈下呈现的情绪启动面孔的愉悦度,分为高、低两个水平。被试的任务是对中性靶刺激面孔进行情绪判断。结果发现:被试在对靶刺激进行情绪判断时出现与启动刺激愉悦度趋于一致的启动效应;低愉悦度面孔作启动刺激条件下N1和P2的波幅显著大于高愉悦度面孔作为启动刺激的条件;不同愉悦度情绪面孔的阈下启动效应是由于启动刺激影响了对靶刺激的知觉加工所致。     

The effect of familiarity on face adaptation

Face aftereffects can provide information on how faces are stored by the human visual system (eg Leopold et al, 2001 Nature Neuroscience 4 89-94), but few studies have used robustly represented (highly familiar) faces. In this study we investigated the influence of facial familiarity on adaptation effects. Participants were adapted to a series of distorted faces (their own face, a famous face, or an unfamiliar face). In experiment 1, figural aftereffects were significantly smaller when participants were adapted to their own face than when they were adapted to the other faces (ie their own face appeared significantly less distorted than a famous or unfamiliar face). Experiment 2 showed that this 'own-face' effect did not occur when the same faces were used as adaptation stimuli for participants who were unfamiliar with them. Experiment 3 replicated experiment 1, but included a pre-adaptation baseline. The results highlight the importance of considering facial familiarity when conducting research on face aftereffects.     

Specificity of face processing without awareness

The recognition memory for inverted faces is especially difficult when compared with that for non-face stimuli. This face inversion effect has often been used as a marker of face-specific holistic processing. However, whether face processing without awareness is still specific remains unknown. The present study addressed this issue by examining the face inversion effect with the technique of binocular rivalry. Results showed that invisible upright faces could break suppression faster than invisible inverted faces. Nevertheless, no difference was found for invisible upright houses and invisible inverted houses. This suggested that face processing without awareness is still specific. Some face-specific information can be processed by high-level brain areas even when that information is invisible.     

Preferential processing of self-relevant stimuli occurs mainly at the perceptual and conscious stages of information processing

Self-related stimuli, such as one’s own name or face, are processed faster and more accurately than other types of stimuli. However, what remains unknown is at which stage of the information processing hierarchy this preferential processing occurs. Our first aim was to determine whether preferential self-processing involves mainly perceptual stages or also post-perceptual stages. We found that self-related priming was stronger than other-related priming only because of perceptual prime-target congruency. Our second aim was to dissociate the role of conscious and unconscious factors in preferential self-processing. To this end, we compared the “self” and “other” conditions in trials where primes were masked or unmasked. In two separate experiments, we found that self-related priming was stronger than other-related priming but only in the unmasked trials. Together, our results suggest that preferential access to the self-concept occurs mainly at the perceptual and conscious stages of the stimulus processing hierarchy.     

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.     

Don’t make me angry,you wouldn’t like me when I’m angry: Volitional choices to act or inhibit are modulated by subliminal perception of emotional faces

Volitional action and self-control—feelings of acting according to one’s own intentions and in being control of one’s own actions—are fundamental aspects of human conscious experience. However, it is unknown whether high-level cognitive control mechanisms are affected by socially salient but nonconscious emotional cues. In this study, we manipulated free choice decisions to act or withhold an action by subliminally presenting emotional faces: In a novel version of the Go/NoGo paradigm, participants made speeded button-press responses to Go targets, withheld responses to NoGo targets, and made spontaneous, free choices to execute or withhold the response for Choice targets. Before each target, we presented emotional faces, backwards masked to render them nonconscious. In Intentional trials, subliminal angry faces made participants more likely to voluntarily withhold the action, whereas fearful and happy faces had no effects. In a second experiment, the faces were made supraliminal, which eliminated the effects of angry faces on volitional choices. A third experiment measured neural correlates of the effects of subliminal angry faces on intentional choice using EEG. After replicating the behavioural results found in Experiment 1, we identified a frontal-midline theta component—associated with cognitive control processes—which is present for volitional decisions, and is modulated by subliminal angry faces. This suggests a mechanism whereby subliminally presented “threat” stimuli affect conscious control processes. In summary, nonconscious perception of angry faces increases choices to inhibit, and subliminal influences on volitional action are deep seated and ecologically embedded.     

阈下安全启动改善非安全依恋女性的注意加工

研究采用掩蔽启动范式，结合事件相关电位技术，考察阈下安全启动在非安全依恋女性对婴儿面孔注意加工上的改善效应。行为指标上，悲伤程度评分和反应时结果均表明了安全启动的改善作用。ERP结果上，在早期注意加工阶段，阈下安全启动比中性启动诱发了依恋焦虑和依恋回避女性对婴儿面孔表情更大的N1波幅以及更优的P2潜伏期，在晚期控制注意加工相关的P3波幅上同样发现了类似的改善效应。研究结果表明阈下安全启动能够提升非安全依恋女性对婴儿面孔的知觉敏感性，改善非安全依恋女性注意加工缺陷，且这种改善效应不仅仅作用于早期注意加工阶段而且还可以扩展到个体有意识的晚期控制加工阶段。