Longitudinal study of personal space in autism.

The size and regulation of personal space are reportedly atypical in autistic individuals. As personal space regulates social interaction, its developmental change is essential for understanding the nature of social difficulties that autistic individuals face. Adolescence is an important developmental period in which social relationships become complex. We conducted a three-year longitudinal study of interpersonal distances in autistic and typically developing (TD) individuals aged 12-18 years at Time 1 and 15-21 years at Time 2. Their preferred interpersonal distances were measured when an experimenter approached the participants with and without eye contact. The interpersonal distances of autistic individuals were shorter than those of TD individuals at both Time 1 and Time 2. Furthermore, the interpersonal distances of autistic individuals at Time 1 and Time 2 were highly correlated, but no such correlation was found in TD individuals. The results suggest that the interpersonal distances of autistic individuals are stable and that the shorter preferred interpersonal distances in autistic individuals compared to those of TD individuals are maintained during adolescence.

Attention to live eye contact in adolescents with autism spectrum disorder.

A number of studies have reported diminished attention to the eyes in individuals with autism spectrum disorder (ASD). These studies predominantly used static images of faces as stimuli. Recent studies, however, have shown enhanced response to eye contact in typically developing (TD) individuals when they observe a person in a live interaction. We investigated physiological orienting to perceived eye contact in adolescents with ASD and TD adolescents when they observed a person in live interaction or viewed a photograph of the same person's face. We measured heart rate (HR) deceleration as an index of attentional orienting. Adolescents with ASD, as well as TD adolescents, showed significant HR deceleration for the direct gaze compared to an averted gaze in the live condition, but not in the photographic condition. The results suggest an intact response to perceived eye contact in individuals with ASD during a live face-to-face interaction. LAY SUMMARY: Individuals with autism spectrum disorder (ASD) have a different eye gaze pattern when observing photographic faces. However, little is known about how individuals with ASD process a real person's face. We measured heart rate (HR) and found that adolescents with ASD showed the typical decline in HR when they made eye contact with a real person, which suggests that both groups of individuals directed their attention to eye contact in a live face-to-face interaction.

Mind perception and moral judgment in autism.

Social difficulties of autistic individuals have been suggested to be caused by mind blindness, the absence of a theory of mind. Numerous studies have investigated theory of mind in autism spectrum disorder or how autistic individuals represent the mental states of others. Here, we have examined, as an alternative, mind perception, namely how individuals perceive the minds of various animate and inanimate entities. Autistic and non-autistic participants demonstrated evidence of a similar two-dimensional mind perception; agency, capacity for doing (i.e., self-control, memory, plan), and experience, capacity for feeling (i.e., fear, hunger, pain). Some targets (e.g., human infant and dog) were perceived to have low agency but high experience, while others (e.g., robot and God) were perceived to have the reverse pattern. Moreover, in both autistic and non-autistic groups, the attribution of moral blame positively correlated with agency, whereas moral consideration positively correlated with experience. These results offer new evidence of social cognition, particularly conception of mind and morality, in autism. Autism Res 2018, 11: 1239-1244. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: We found that autistic and non-autistic individuals have similar thoughts regarding the minds of various living and nonliving entities. In addition, both groups gave moral consideration or blamed entities for wrongdoing according to their conception of the minds of those entities. Autistic individuals have this mind-based moral sense, which is a pivotal element with a key role in human society.

Preferential awareness of protofacial stimuli in autism.

It has been suggested that a subcortically mediated, innate sensitivity to protofacial stimuli leads to specialized face processing and to the development of the social brain. A dysfunction of this face-processing pathway has been associated with atypical social development in individuals with autism spectrum disorder (ASD). This study investigated whether individuals with ASD exhibit primary sensitivity to monochrome protoface stimuli using continuous flash suppression (CFS). Under CFS, visual stimuli are suppressed from awareness, and cortical processing is strongly reduced while subcortical regions continue to respond to invisible stimuli. We found that both adolescents with ASD and typically developing adolescents showed preferential detection of upright protoface stimuli under CFS but not in a non-CFS control condition. These results challenge the notion that a primitive sensitivity to protoface stimuli is essential for typical social development. Rather, our findings suggest such sensitivity is not a sufficient condition for typical social development and that the presence of other complementary factors is necessary for the development of the social brain.

Absence of preferential unconscious processing of eye contact in adolescents with autism spectrum disorder.

Eye contact plays an essential role in social interaction. Atypical eye contact is a diagnostic and widely reported feature of autism spectrum disorder (ASD). Here, we determined whether altered unconscious visual processing of eye contact might underlie atypical eye contact in ASD. Using continuous flash suppression (CFS), we found that typically developing (TD) adolescents detected faces with a direct gaze faster than faces with an averted gaze, indicating enhanced unconscious processing of eye contact. Critically, adolescents with ASD did not show different durations of perceptual suppression for faces with direct and averted gaze, suggesting that preferential unconscious processing of eye contact is absent in this group. In contrast, in a non-CFS control experiment, both adolescents with ASD and TD adolescents detected faces with a direct gaze faster than those with an averted gaze. Another CFS experiment confirmed that unconscious processing of non-social stimuli is intact for adolescents with ASD. These results suggest that atypical processing of eye contact in individuals with ASD could be related to a weaker initial, unconscious registration of eye contact.

Neural and behavioural responses to face-likeness of objects in adolescents with autism spectrum disorder.

Numerous studies have revealed atypical face processing in autism spectrum disorders (ASD) characterized by social interaction and communication difficulties. This study investigated sensitivity to face-likeness in ASD. In Experiment 1, we found a strong positive correlation between the face-likeness ratings of non-face objects in the ASD (11-19 years old) and the typically developing (TD) group (9-21 years old). In Experiment 2 (the scalp-recorded event-related potential experiment), the participants of both groups (ASD, 12-19 years old; TD, 12-18 years old) exhibited an enhanced face-sensitive N170 amplitude to a face-like object. Whereas the TD adolescents showed an enhanced N170 during the face-likeness judgements, adolescents with ASD did not. Thus, both individuals with ASD and TD individuals have a perceptual and neural sensitivity to face-like features in objects. When required to process face-like features, a face-related brain system reacts more strongly in TD individuals but not in individuals with ASD.

Presence of contagious yawning in children with autism spectrum disorder.

Most previous studies suggest diminished susceptibility to contagious yawning in children with autism spectrum disorder (ASD). However, it could be driven by their atypical attention to the face. To test this hypothesis, children with ASD and typically developing (TD) children were shown yawning and control movies. To ensure participants' attention to the face, an eye tracker controlled the onset of the yawning and control stimuli. Results demonstrated that both TD children and children with ASD yawned more frequently when they watched the yawning stimuli than the control stimuli. It is suggested therefore that the absence of contagious yawning in children with ASD, as reported in previous studies, might relate to their weaker tendency to spontaneously attend to others' faces.

Cultural modulation of face and gaze scanning in young children.

Previous research has demonstrated that the way human adults look at others' faces is modulated by their cultural background, but very little is known about how such a culture-specific pattern of face gaze develops. The current study investigated the role of cultural background on the development of face scanning in young children between the ages of 1 and 7 years, and its modulation by the eye gaze direction of the face. British and Japanese participants' eye movements were recorded while they observed faces moving their eyes towards or away from the participants. British children fixated more on the mouth whereas Japanese children fixated more on the eyes, replicating the results with adult participants. No cultural differences were observed in the differential responses to direct and averted gaze. The results suggest that different patterns of face scanning exist between different cultures from the first years of life, but differential scanning of direct and averted gaze associated with different cultural norms develop later in life.

Cultural background modulates how we look at other persons' gaze.

The current study investigated the role of cultural norms on the development of face-scanning. British and Japanese adults' eye movements were recorded while they observed avatar faces moving their mouth, and then their eyes toward or away from the participants. British participants fixated more on the mouth, which contrasts with Japanese participants fixating mainly on the eyes. Moreover, eye fixations of British participants were less affected by the gaze shift of the avatar than Japanese participants, who shifted their fixation to the corresponding direction of the avatar's gaze. Results are consistent with the Western cultural norms that value the maintenance of eye contact, and the Eastern cultural norms that require flexible use of eye contact and gaze aversion.

Attention to eye contact in the West and East: autonomic responses and evaluative ratings.

Eye contact has a fundamental role in human social interaction. The special appearance of the human eye (i.e., white sclera contrasted with a coloured iris) implies the importance of detecting another person's face through eye contact. Empirical studies have demonstrated that faces making eye contact are detected quickly and processed preferentially (i.e., the eye contact effect). Such sensitivity to eye contact seems to be innate and universal among humans; however, several studies suggest that cultural norms affect eye contact behaviours. For example, Japanese individuals exhibit less eye contact than do individuals from Western European or North American cultures. However, how culture modulates eye contact behaviour is unclear. The present study investigated cultural differences in autonomic correlates of attentional orienting (i.e., heart rate) and looking time. Additionally, we examined evaluative ratings of eye contact with another real person, displaying an emotionally neutral expression, between participants from Western European (Finnish) and East Asian (Japanese) cultures. Our results showed that eye contact elicited stronger heart rate deceleration responses (i.e., attentional orienting), shorter looking times, and higher ratings of subjective feelings of arousal as compared to averted gaze in both cultures. Instead, cultural differences in the eye contact effect were observed in various evaluative responses regarding the stimulus faces (e.g., facial emotion, approachability etc.). The rating results suggest that individuals from an East Asian culture perceive another's face as being angrier, unapproachable, and unpleasant when making eye contact as compared to individuals from a Western European culture. The rating results also revealed that gaze direction (direct vs. averted) could influence perceptions about another person's facial affect and disposition. These results suggest that cultural differences in eye contact behaviour emerge from differential display rules and cultural norms, as opposed to culture affecting eye contact behaviour directly at the physiological level.

Brief report: pointing cues facilitate word learning in children with autism spectrum disorder.

Children with autism spectrum disorder (ASD) reportedly have difficulty associating novel words to an object via the speaker's gaze. It has also been suggested that their performance is related to their gaze duration on the object and improves when the object moves and becomes more salient. However, there is a possibility that they have only relied on the object's movement and have not referenced the speaker's cue (i.e. gaze direction). The current study with children with ASD and typically developing children aged 6-11 years demonstrated that adding another speaker's cue (i.e. pointing) improves the performance of children with ASD. This suggests that additional speaker's cues may help referential word learning in children with ASD.

Atypical disengagement from faces and its modulation by the control of eye fixation in children with autism spectrum disorder.

By using the gap overlap task, we investigated disengagement from faces and objects in children (9-17 years old) with and without autism spectrum disorder (ASD) and its neurophysiological correlates. In typically developing (TD) children, faces elicited larger gap effect, an index of attentional engagement, and larger saccade-related event-related potentials (ERPs), compared to objects. In children with ASD, by contrast, neither gap effect nor ERPs differ between faces and objects. Follow-up experiments demonstrated that instructed fixation on the eyes induces larger gap effect for faces in children with ASD, whereas instructed fixation on the mouth can disrupt larger gap effect in TD children. These results suggest a critical role of eye fixation on attentional engagement to faces in both groups.

Atypical modulation of face-elicited saccades in autism spectrum disorder in a double-step saccade paradigm.

Atypical development of face processing is a major characteristic in autism spectrum disorder (ASD), which could be due to atypical interactions between subcortical and cortical face processing. The current study investigated the saccade planning towards faces in ASD. Seventeen children with ASD and 17 typically developing (TD) children observed a pair of upright or inverted face configurations flashed sequentially in two different spatial positions. The reactive saccades of participants were recorded by eye-tracking. The results did not provide evidence of overall impairment of subcortical route in ASD, However, the upright, but not the inverted, face configuration modulated the frequency of vector sum saccades (an index of subcortical control) in TD, but not in ASD. The current results suggests that children with ASD do not have overall impairment of the subcortital route, but the subcortical route may not be specialized to face processing.

The effect of gaze direction on the processing of facial expressions in children with autism spectrum disorder: an ERP study.

This study investigated the neural basis of the effect of gaze direction on facial expression processing in children with and without ASD, using event-related potential (ERP). Children with ASD (10-17-year olds) and typically developing (TD) children (9-16-year olds) were asked to determine the emotional expressions (anger or fearful) of a facial stimulus with a direct or averted gaze, and the ERPs were recorded concurrently. In TD children, faces with a congruent expression and gaze direction in approach-avoidance motivation, such as an angry face with a direct gaze (i.e., approaching motivation) and a fearful face with an averted gaze (i.e., avoidant motivation), were recognized more accurately and elicited larger N170 amplitudes than motivationally incongruent facial stimuli (an angry face with an averted gaze and a fearful face with a direct gaze). These results demonstrated the neural basis and time course of integration of facial expression and gaze direction in TD children and its impairment in children with ASD.

Does gaze direction modulate facial expression processing in children with autism spectrum disorder?

Two experiments investigated whether children with autism spectrum disorder (ASD) integrate relevant communicative signals, such as gaze direction, when decoding a facial expression. In Experiment 1, typically developing children (9-14 years old; n = 14) were faster at detecting a facial expression accompanying a gaze direction with a congruent motivational tendency (i.e., an avoidant facial expression with averted eye gaze) than those with an incongruent motivational tendency. Children with ASD (9-14 years old; n = 14) were not affected by the gaze direction of facial stimuli. This finding was replicated in Experiment 2, which presented only the eye region of the face to typically developing children (n = 10) and children with ASD (n = 10). These results demonstrated that children with ASD do not encode and/or integrate multiple communicative signals based on their affective or motivational tendency.

Brief report: does eye contact induce contagious yawning in children with autism spectrum disorder?

Individuals with autism spectrum disorder (ASD) reportedly fail to show contagious yawning, but the mechanism underlying the lack of contagious yawning is still unclear. The current study examined whether instructed fixation on the eyes modulates contagious yawning in ASD. Thirty-one children with ASD, as well as 31 age-matched typically developing (TD) children, observed video clips of either yawning or control mouth movements. Participants were instructed to fixate to the eyes of the face stimuli. Following instructed fixation on the eyes, both TD children and children with ASD yawned equally frequently in response to yawning stimuli. Current results suggest that contagious yawning could occur in ASD under an experimental condition in which they are instructed to fixate on the yawning eyes.