Looking at Eye Gaze Processing and Its Neural Correlates in Infancy—Implications for Social Development and Autism Spectrum Disorder

The importance of eye gaze as a means of communication is indisputable. However, there is debate about whether there is a dedicated neural module, which functions as an eye gaze detector and when infants are able to use eye gaze cues in a referential way. The application of neuroscience methodologies to developmental psychology has provided new insights into early social cognitive development. This review integrates findings on the development of eye gaze processing with research on the neural mechanisms underlying infant and adult social cognition. This research shows how a cognitive neuroscience approach can improve our understanding of social development and autism spectrum disorder.     

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.     

Evidence for referential understanding in the emotions domain at twelve and eighteen months

Infants as young as 12 months readily modulate their behavior toward novel, ambiguous objects based on emotional responses that others display. Such social-referencing skill offers powerful benefits to infants' knowledge acquisition, but the magnitude of these benefits depends on whether they appreciate the referential quality of others' emotional messages, and are skilled at using cues to reference (e.g., gaze direction, body posture) to guide their interpretation of such messages. Two studies demonstrated referential understanding in 12- and 18-month-olds' responses to another's emotional outburst. Infants relied on the presence versus absence of referential cues to determine whether an emotional message should be linked with a salient, novel object in the first study (N = 48), and they actively consulted referential cues to disambiguate the intended target of an affective display in the second study (N = 32). These findings provide the first experimental evidence of such sophisticated referential abilities in 12-month-olds, as well as the first evidence that infant social referencing at any age actually trades on referential understanding.     

Usage of statistical cues for word boundary in reading Chinese sentences

The present study examined the use of statistical cues for word boundaries during Chinese reading. Participants were instructed to read sentences for comprehension with their eye movements being recorded. A two-character target word was embedded in each sentence. The contrast between the probabilities of the ending character (C2) of the target word (C12) being used as word beginning and ending in all words containing it was manipulated. In addition, by using the boundary paradigm, parafoveal overlapping ambiguity in the string C123 was manipulated with three types of preview of the character C3, which was a single-character word in the identical condition. During preview, the combination of C23′ was a legal word in the ambiguous condition and was not a word in the control condition. Significant probability and preview effects were observed. In the low-probability condition, inconsistency in the frequent within-word position (word beginning) and the present position (word ending) lengthened gaze durations and increased refixation rate on the target word. Although benefits from the identical previews were apparent, effects of overlapping ambiguity were negligible. The results suggest that the probability of within-word positions had an influence during character-to-word assignment, which was mainly verified during foveal processing. Thus, the overlapping ambiguity between parafoveal words did not interfere with reading. Further investigation is necessary to examine whether current computational models of eye movement control should incorporate statistical cues for word boundaries together with other linguistic factors in their word processing system to account for Chinese reading.     

Preschoolers Use Emotion in Speech to Learn New Words

Two experiments examined 4‐ and 5‐year‐olds' use of vocal affect to learn new words. In Experiment 1 (n = 48), children were presented with two unfamiliar objects, first in their original state and then in an altered state (broken or enhanced). An instruction produced with negative, neutral, or positive affect, directed children to find the referent of a novel word. During the novel noun, eye gaze measures indicated that both 4‐ and 5‐year‐olds were more likely to consider an object congruent with vocal affect cues. In Experiment 2, 5‐year‐olds (n = 15) were asked to extend and generalize their initial mapping to new exemplars. Here, 5‐year‐olds generalized these newly mapped labels but only when presented with negative vocal affect.     

Neural Processing of Eye Gaze and Threat‐Related Emotional Facial Expressions in Infancy

Combined with emotional expressions, eye gaze can provide essential information to indicate threat in the environment. The current study assessed the effects of eye gaze direction on infants’ neural processing of fearful and angry faces. Event‐related potentials were recorded from thirteen 7‐month‐old infants. Two face‐sensitive posterior components, the N290 and P400, as well as a frontocentral negative component (Nc), indicating attentional arousal, were sensitive to eye gaze direction and emotion. A larger Nc was observed for angry faces with direct compared to averted eye gaze. Fearful faces elicited a larger N290 than angry faces, whereas angry faces elicited a more prominent P400 regardless of eye gaze direction. The findings are discussed in terms of early social cognitive and neural development.     

Effects of Reinforcement Learning on Gaze Following of Gaze and Head Direction in Early Infancy: An Interactive Eye-Tracking Study

The current four experiments investigated gaze following behavior in response to gaze and head turns in 4-month-olds and how reinforcement learning influences this behavior (N = 99). Using interactive eye tracking, infants’ gaze elicited an animation whenever infants followed a person’s head or gaze orientation (Experiment 1.1, 2.1 and 2.2) or looked at the opposite side (Experiment 1.2). Infants spontaneously followed the direction of a turning head with and without simultaneously shifted gaze direction (Cohen’s d: 0.93–1.05) but not the direction of isolated gaze shifts. We only found a weak effect of reinforcement on gaze following in one of the four experiments. Results will be discussed with regard to the impact of reinforcement on the maintenance of already existing gaze following behavior.     

Development of Phonological Constancy: 19‐Month‐Olds,but Not 15‐Month‐Olds,Identify Words in a Non‐Native Regional Accent

By 12 months, children grasp that a phonetic change to a word can change its identity (phonological distinctiveness). However, they must also grasp that some phonetic changes do not (phonological constancy). To test development of phonological constancy, sixteen 15‐month‐olds and sixteen 19‐month‐olds completed an eye‐tracking task that tracked their gaze to named versus unnamed images for familiar words spoken in their native (Australian) and an unfamiliar non‐native (Jamaican) regional accent of English. Both groups looked longer at named than unnamed images for Australian pronunciations, but only 19‐month‐olds did so for Jamaican pronunciations, indicating that phonological constancy emerges by 19 months. Vocabulary size predicted 15‐month‐olds' identifications for the Jamaican pronunciations, suggesting vocabulary growth is a viable predictor for phonological constancy development.     

Automatic attention cueing through eye movement in 2-year-old children with autism

Automatic attention cueing by perceived changes in gaze direction was studied in 2-year-old children with autism and typically developing (TD) controls using a visual attention cueing paradigm. In Experiments 1 and 2 the cue consisted of an eye movement (Eyes) and a nonbiological movement (SimEyes), respectively. The results suggest that visual attention in children with autism and their TD counterparts is cued by perceived eye movement. Thus, although in naturalistic situations toddlers with autism do not follow the gaze of others, they are sensitive to directional cues inherent in eye movement. Cue-specific differences in performance related to the level of engagement and cue-processing time may suggest reliance on different underlying strategies for gaze processing in autism.     

Gliding text: a new aid to improve the reading performance of poor readers by subconscious gaze control

In support of efforts at reducing the number of dyslexics and illiterates in industrialized countries it is proposed, for the first time, to use gliding text ‐ as known in television subtitles ‐ as a method of text display to help those learning to read. Beginners, having the difficult task of precisely directing their gaze letter by letter along the line of text, experience with gliding text automatic gaze guidance as in so‐called ‘optokinetic nystagmus’. This subconscious gaze control allows beginners to pay more attention to contextual processing. First training courses have shown that exercises with gliding text are very efficient. Reading difficulties were eliminated for 21 second‐grade elementary school children in only 24 training sessions, each of 15 min duration. The mean reading speed increased from ten to 24 words per minute (WPM).     

Revisiting Patterson's paradigm: gaze behaviors in deaf communication

Eye contact and eye gaze behaviors within communication contexts are considered vital to clear linguistic transmission. Although much research has been done on eye contact and gaze behaviors, surprisingly little literature exists in this area concerning deaf populations. Due to linguistic necessity, certain factors influencing gaze behaviors during communication will differ between hearing and deaf groups. The present article explains a sequential model of eye gaze and eye contact behaviors (Patterson, 1982) developed and researched among hearing populations and explores possible similarities and differences in these behaviors in deaf people. It is found that characterizations of eye contact and eye gaze behaviors applied to hearing populations are not completely applicable to deaf groups. Empirical research is needed to validate the ideas presented here, and future research directions are indicated.     

The role of social-referential context in verbal and nonverbal symbol learning

This study examined the role of social-referential context in 13- and 18-month-olds' mapping of verbal and nonverbal symbols to object categories. Infants heard either novel words or novel nonverbal sounds in either a referential or nonreferential context. In all conditions, an experimenter engaged in a social-referential interaction and the label was produced while the infant's attention was directed to the referent. In the referential condition, labels were produced by the experimenter within the context of a familiar naming routine. In the nonreferential condition, labels were emitted from a baby monitor placed near the infant. The study subsequently tested infants' mapping of the symbols to the referent objects using a forced-choice procedure. Although the results for the 18-month-olds were strongest, infants at both ages showed evidence of learning both words and sounds in the referential condition and failed to learn them in the nonreferential condition. Thus, infants successfully learned both words and sounds under the same circumstances at both ages. These findings suggest that the social-referential context, and not the symbolic form per se, determine infants' success at symbol learning.     

Children’s Social Information Seeking is Sensitive to Referential Ambiguity

We examined children’s spontaneous information seeking in response to referential ambiguity. Children ages 2–5 (n = 160) identified the referents of familiar and novel labels. We manipulated ambiguity by changing the number of objects present and their familiarity (Experiments 1 and 2), and the availability of referential gaze (Experiment 2). In both experiments, children looked to the face of the experimenter more often while responding, specifically when the referent was ambiguous. In Experiment 2, 3- to 4-year olds also demonstrated sensitivity to graded referential evidence. These results suggest that social information seeking is an active learning behavior that could contribute to language acquisition in early childhood.     

How to guide learners' processing of multimedia lessons with pedagogical agents

Two experiments examined the effects of a pedagogical agent's (PA's) pointing gestures, eye gaze, and eye contact on learning processes (measured by learners' eye fixations on relevant elements) and learning outcomes (as measured by retention and transfer test scores) with a multimedia lesson on neural transmission. In Experiment 1, having the PA look at and point to relevant elements as she lectured led to more eye fixations on the relevant portion of the graphic and better retention and transfer test scores. Keeping eye contact with learners tended to improve retention test scores and increased their eye fixations on relevant elements when the PA also looked at and pointed to the graphic. In Experiment 2, the PA's pointing gestures as a stand-alone feature caused better retention test scores and more fixations on relevant elements of the graphic, but eye gaze direction did not. These findings help extend the embodiment principle.     

Referential Labeling Can Facilitate Phonetic Learning in Infancy

All languages employ certain phonetic contrasts when distinguishing words. Infant speech perception is rapidly attuned to these contrasts before many words are learned, thus phonetic attunement is thought to proceed independently of lexical and referential knowledge. Here, evidence to the contrary is provided. Ninety‐eight 9‐month‐old English‐learning infants were trained to perceive a non‐native Cantonese tone contrast. Two object–tone audiovisual pairings were consistently presented, which highlighted the target contrast (Object A with Tone X; Object B with Tone Y). Tone discrimination was then assessed. Results showed improved tone discrimination if object–tone pairings were perceived as being referential word labels, although this effect was modulated by vocabulary size. Results suggest how lexical and referential knowledge could play a role in phonetic attunement.     

Infants' developing understanding of social gaze

Young infants are sensitive to self‐directed social actions, but do they appreciate the intentional, target‐directed nature of such behaviors? The authors addressed this question by investigating infants’ understanding of social gaze in third‐party interactions (N = 104). Ten‐month‐old infants discriminated between 2 people in mutual versus averted gaze, and expected a person to look at her social partner during conversation. In contrast, 9‐month‐old infants showed neither ability, even when provided with information that highlighted the gazer’s social goals. These results indicate considerable improvement in infants’ abilities to analyze the social gaze of others toward the end of their 1st year, which may relate to their appreciation of gaze as both a social and goal‐directed action.     

12-month-olds' phonotactic knowledge guides their word-object mappings

This study examined whether 12‐month‐olds will accept words that differ phonologically and phonetically from their native language as object labels in an associative learning task. Sixty infants were presented with sets of English word–object (N = 30), Japanese word–object (N = 15), or Czech word–object (N = 15) pairings until they habituated. Infants associated CVCV English, CCVC English, and CVCV Japanese words, but not CCVC Czech words, with novel objects. These results demonstrate that by 12 months of age, infants are beginning to apply their language‐specific knowledge to their acceptance of word forms. That is, they will not map words that violate the phonotactics of their native language to objects.     

Orthographic analysis of words during fluency training promotes reading of new similar words

Remediation of a serious lack in reading fluency often takes the form of repeated reading exercises. The present study examines whether transfer of training effects to untrained (neighbour) words can be enhanced by training with an orthographic focus as compared with emphasising semantics. The effect of oral versus silent reading during training is studied as well. Two groups of reading‐disabled children (mean age=7 years, 11 months) were given repeated reading training with limited exposure duration (350 ms) in which 15 target words were repeated 20 times in exercises focused on either orthography (N=26) or semantics (N=25). The children were required to either read the target words aloud or perform the exercises silently, but this requirement appeared to have no effect on the training results. The results show that untrained neighbour words benefited more from training targets with an orthographic focus than from exercises with a semantic emphasis.