Object label and category knowledge among toddlers at risk for autism spectrum disorder: An application of the visual array task.

Individuals diagnosed with autism spectrum disorder (ASD) demonstrate atypical development of receptive language and object category knowledge. Yet, little is known about the emerging relation between these two competencies in this population. The present study utilized a gaze-based paradigm, the visual array task (VAT), to examine the relation between object label and object category knowledge in a sample of toddlers at heightened genetic risk for developing ASD. Eighty-eight toddlers with at least one typically developing older sibling (low-risk; LR) or one older sibling diagnosed with ASD (high-risk; HR) completed the VAT at 17 (LR n = 20; HR n = 27) and/or 25 months of age (LR n = 42; HR n = 22). Results indicated that the VAT was both a sensitive measure of receptive vocabulary as well as capable of reflecting gains in category knowledge for toddlers at genetic risk of developing ASD. Notably, an early emerging difference in the relation between target label knowledge and category knowledge for the groups was observed at 17 months of age but dissipated by 25 months of age. This suggests that while the link between receptive vocabulary and category knowledge may develop earlier in LR groups, HR groups may potentially catch up by the second year of life. Therefore, it is likely meaningful to consider differences in category knowledge when conceptualizing the receptive language deficits associated with HR populations. During language learning, typically developing children are sensitive to the common features of category members and use this information to generalize known object labels to newly encountered exemplars. The inability to identify similarities between category members and/or utilize this information when learning new object referents at 17 months of age may be a potential mechanism underlying the delays observed in HR populations.

The visual array task: A novel gaze-based measure of object label and category knowledge.

Visual attention measures of receptive vocabulary place minimal task demand on participants and produce a more accurate measure of language comprehension than parent report measures. However, current gaze-based measures employ visual comparisons limited to two simultaneous items. With this limitation, the degree of similarity of the target to the distractor can have a significant impact on the interpretation of task performance. The current study evaluates a novel gaze-based paradigm that includes an eight-item array. This visual array task (VAT) combines the theoretical frameworks of the Intermodal Preferential Looking Paradigm (IPLP) and looking-while-listening (LWL) methods of language comprehension measurement but using a larger array of simultaneously presented items. The use of a larger array of items and the inclusion of a superordinate category contrast may provide a more sensitive measure of receptive vocabulary as well as an understanding of the extent to which early word comprehension reflects knowledge of broader categories. Results indicated that the tested VAT was a sensitive measure of both object label and category knowledge. This paradigm provides researchers with a flexible and efficient task to measure language comprehension and category knowledge while reducing behavioral demands placed on participants.

Development and Validation of Objective and Quantitative Eye Tracking-Based Measures of Autism Risk and Symptom Levels.

OBJECTIVE: The primary aim of this study was to develop and validate eye tracking-based measures for estimating autism spectrum disorder (ASD) risk and quantifying autism symptom levels. METHOD: Eye tracking data were collected from youth during an initial evaluation visit, with administrators blinded to all clinical information. Consensus diagnoses were given by the multidisciplinary team. Participants viewed a 5-minute video that included 44 dynamic stimuli from 7 distinct paradigms while gaze was recorded. Gaze metrics were computed for temporally defined regions of interest. Autism risk and symptom indices aggregated gaze measures showing significant bivariate relationships with ASD diagnosis and Autism Diagnostic Observation Schedule, Second Edition (ADOS-2) symptom severity levels in a training sample (75%, n = 150). Receiver operating characteristic curve analysis and nonparametric correlations were used to cross-validate findings in a test sample (25%; n = 51). RESULTS: Most children (n = 201, 92%) completed a valid eye tracking assessment (ages 1.6─17.6; 80% male; ASD n = 91, non-ASD n = 110). In the test subsample, the autism risk index had high accuracy for ASD diagnosis (area under the curve [AUC] = 0.86, 95% CI =0.75-0.95), whereas the autism symptom index was strongly associated with ADOS-2 total severity scores (r = 0.41, p < .001). Validity was not substantively attenuated after adjustment for language, nonverbal cognitive ability, or other psychopathology symptoms (r = 0.40-0.67, p > .001). CONCLUSION: Eye tracking measures appear to be useful quantitative, objective measures of ASD risk and autism symptom levels. If independently replicated and scaled for clinical use, eye tracking-based measures could be used to inform clinical judgment regarding ASD identification and to track autism symptom levels.

Development of an Objective Autism Risk Index Using Remote Eye Tracking.

OBJECTIVE: Abnormal eye gaze is a hallmark characteristic of autism spectrum disorder (ASD), and numerous studies have identified abnormal attention patterns in ASD. The primary aim of the present study was to create an objective, eye tracking-based autism risk index. METHOD: In initial and replication studies, children were recruited after referral for comprehensive multidisciplinary evaluation of ASD and subsequently grouped by clinical consensus diagnosis (ASD n = 25/15, non-ASD n = 20/19 for initial/replication samples). Remote eye tracking was blinded to diagnosis and included multiple stimuli. Dwell times were recorded to each a priori-defined region of interest (ROI) and averaged across ROIs to create an autism risk index. Receiver operating characteristic curve analyses examined classification accuracy. Correlations with clinical measures evaluated whether the autism risk index was associated with autism symptom severity independent of language ability. RESULTS: In both samples, the autism risk index had high diagnostic accuracy (area under the curve [AUC] = 0.91 and 0.85, 95% CIs = 0.81-0.98 and 0.71-0.96), was strongly associated with Autism Diagnostic Observation Schedule-Second Edition (ADOS-2) severity scores (r = 0.58 and 0.59, p < .001), and not significantly correlated with language ability (r ≤| -0.28|, p > .095). CONCLUSION: The autism risk index may be a useful quantitative and objective measure of risk for autism in at-risk settings. Future research in larger samples is needed to cross-validate these findings. If validated and scaled for clinical use, this measure could inform clinical judgment regarding ASD diagnosis and track symptom improvements.

Beyond autism: a baby siblings research consortium study of high-risk children at three years of age.

OBJECTIVE: First-degree relatives of persons with an autism spectrum disorder (ASD) are at increased risk for ASD-related characteristics. As little is known about the early expression of these characteristics, this study characterizes the non-ASD outcomes of 3-year-old high-risk (HR) siblings of children with ASD. METHOD: Two groups of children without ASD participated: 507 HR siblings and 324 low-risk (LR) control subjects (no known relatives with ASD). Children were enrolled at a mean age of 8 months, and outcomes were assessed at 3 years. Outcome measures were Autism Diagnostic Observation Schedule (ADOS) calibrated severity scores, and Mullen Verbal and Non-Verbal Developmental Quotients (DQ). RESULTS: At 3 years, HR siblings without an ASD outcome exhibited higher mean ADOS severity scores and lower verbal and non-verbal DQs than LR controls. HR siblings were over-represented (21% HR versus 7% LR) in latent classes characterized by elevated ADOS severity and/or low to low-average DQs. The remaining HR siblings without ASD outcomes (79%) belonged to classes in which they were not differentially represented with respect to LR siblings. CONCLUSIONS: Having removed a previously identified 18.7% of HR siblings with ASD outcomes from all analyses, HR siblings nevertheless exhibited higher mean levels of ASD severity and lower levels of developmental functioning than LR children. However, the latent class membership of four-fifths of the HR siblings was not significantly different from that of LR control subjects. One-fifth of HR siblings belonged to classes characterized by higher ASD severity and/or lower levels of developmental functioning. This empirically derived characterization of an early-emerging pattern of difficulties in a minority of 3-year-old HR siblings suggests the importance of developmental surveillance and early intervention for these children.

Comparison of eye movements over faces in photographic positives and negatives.

Eye movements were recorded while subjects viewed ordinary portraits and photographic negatives of those portraits. Under both conditions they first studied sixteen portraits and then tried to decide which of forty-eight portraits they had just seen. They made more errors of recognition while viewing negatives, and their fixation patterns were significantly altered: there was a decrease in the percentage of fixations directed to the eyes, nose, and mouth, and an increase for such details as the ears, cheeks, chin, cap, and necktie. There was also a decrease in the ratio of fixations to the most fixated detail compared to the least fixated detail.

Categorization in ASD: The Role of Typicality and Development.

There is a growing amount of evidence suggesting that individuals with autism spectrum disorders (ASD) differ in the way in which they cognitively process information. A critical aspect of cognitive processing that is receiving more attention in studies of ASD is categorization. The studies presented here examined the effect of typicality on categorization of objects and gender in high-functioning children, adolescents, and adults with ASD and matched controls. The ASD and control groups showed improved categorization throughout the lifespan for typical and somewhat typical object category members and typical gender faces. However, individuals with ASD took more time to categorize atypical object category members and were less accurate in categorizing atypical gender faces from 8-12 years through adulthood. The implications of these results for teaching categories and category labels to individuals with ASD will be discussed.

Left visual field biases when infants process faces: a comparison of infants at high- and low-risk for autism spectrum disorder.

While it is well-known that individuals with autism spectrum disorder (ASD) have difficulties processing faces, very little is known about the origins of these deficits. The current study focused on 6- and 11-month-old infants who were at either high-risk (n = 43) or low-risk (n = 31) for developing ASD based on having a sibling already diagnosed with the disorder. Eye-tracking data were collected while the infants viewed color photographs of faces. Similar to previous studies with both typically developing adults and infants, low-risk infants demonstrated a preference for looking at the left side of the face (known as a left visual field bias) that emerged by 11 months of age. In contrast, high-risk infants did not demonstrate a left visual field bias at either age. Comparisons of the amount of attention given to the eye versus mouth regions indicated no differences between the two risk groups.

Category formation in autism: can individuals with autism form categories and prototypes of dot patterns?

There is a growing amount of evidence suggesting that individuals with autism have difficulty with categorization. One basic cognitive ability that may underlie this difficulty is the ability to abstract a prototype. The current study examined prototype and category formation with dot patterns in high-functioning adults with autism and matched controls. Individuals with autism were found to have difficulty forming prototypes and categories of dot patterns. The eye-tracking data did not reveal any between group differences in attention to the dot patterns. However, relationships between performance and intelligence in the autism group suggest possible processing differences between the groups. Results are consistent with previous studies that have found deficits in prototype formation and extend these deficits to dot patterns.

The development of facial gender categorization in individuals with and without autism: the impact of typicality.

While much research has examined the development of facial recognition abilities, less is known about the ability of individuals with and without autism to categorize facial gender. The current study tested gender categorization abilities in high-functioning children (5-7 and 8-12 years), adolescents (13-17 years), and adults (18-53 years) with autism and matched controls. Naturalistic videos depicted faces that were either typical or less typical of each gender. Both groups improved in their performance across development. However, control children reached expertise that was similar to control adults by 8-12 years; whereas, adults with autism never reached this level of expertise, particularly with less typical gender faces. Results suggest that individuals with autism employ different face processing mechanisms than typically developing individuals.

A lack of left visual field bias when individuals with autism process faces.

It has been established that typically developing individuals have a bias to attend to facial information in the left visual field (LVF) more than in the right visual field. This bias is thought to arise from the right hemisphere's advantage for processing facial information, with evidence suggesting it to be driven by the configural demands of face processing. Considering research showing that individuals with autism have impaired face processing abilities, with marked deficits in configural processing, it was hypothesized that they would not demonstrate a LVF bias for faces. Eye-tracking technology was used to show that individuals with autism were not spontaneously biased to facial information in the LVF, in contrast to a control group, while discriminating facial gender.

Can individuals with autism abstract prototypes of natural faces?

There is a growing amount of evidence suggesting that individuals with autism have difficulty with face processing. One basic cognitive ability that may underlie face processing difficulties is the ability to abstract a prototype. The current study examined prototype formation with natural faces using eye-tracking in high-functioning adults with autism and matched controls. Individuals with autism were found to have significant difficulty forming prototypes of natural faces. The eye-tracking data did not reveal any between group differences in the general pattern of attention to the faces, indicating that these difficulties were not due to attentional factors. Results are consistent with previous studies that have found a deficit in prototype formation and extend these deficits to natural faces.

Gender discrimination of eyes and mouths by individuals with autism.

Evidence remains mixed about whether individuals with autism look less to eyes and whether they look more at mouths. Few studies have examined how spontaneous attention to facial features relates to face processing abilities. This study tested the ability to discriminate gender from facial features, namely eyes and mouths, by comparing accuracy scores of 17 children with autism and 15 adults with autism to 17 typically developing children and 15 typically developing adults. Results indicated that all participants regardless of diagnosis discriminated gender more accurately from eyes than from mouths. However, results indicated that compared to adults without autism, adults with autism were significantly worse at discriminating gender from eyes.

Memory awareness for faces in individuals with autism.

Little is known regarding metacognition in individuals with autism. Specifically, it is unclear how individuals with autism think about their own mental states. The current study assessed memory awareness during a facial recognition task. High-functioning children (M = 13.1 years, n = 18) and adults (M = 27.5 years, n = 16) with autism matched with typically developing children (M = 14.3 years, n = 13) and adults (M = 26.9 years, n = 15) were tested. Children with autism demonstrated less accurate memory awareness for faces and less reliable differentiation between their confidence ratings compared to typically developing children. Subtle impairments in memory awareness for faces were also evident in adults with autism. Results indicate that broader metacognitive deficits may exist in individuals with autism, possibly contributing to other known impairments.

Prototype formation in autism: can individuals with autism abstract facial prototypes?

Prototype formation is a critical skill for category learning. Research suggests that individuals with autism may have a deficit in prototype formation of some objects; however, results are mixed. This study used a natural category, faces, to further examine prototype formation in high-functioning individuals with autism. High-functioning children (age 8-13 years) and adults with autism (age 17-53 years) and matched controls were tested in a facial prototype formation task that has been used to test prototype formation abilities in typically developing infants and adults [Strauss, 1979]. Participants were familiarized to a series of faces depicting subtle variations in the spatial distance of facial features, and were then given a forced choice familiarity test between the mean prototype and the mode prototype. Overall, individuals in the autism group were significantly less likely to select the mean prototype face. Even though the children with autism showed this difference in prototype formation, this pattern was driven primarily by the adults, because the adults with autism were approximately four times less likely to select the mean prototype than were the control adults. These results provide further evidence that individuals with autism have difficulty abstracting subtle spatial information that is necessary not only for the formation of a mean prototype, but also for categorizing faces and objects.

The development of emotion recognition in individuals with autism.

Emotion recognition was investigated in typically developing individuals and individuals with autism. Experiment 1 tested children (5-7 years, n = 37) with brief video displays of facial expressions that varied in subtlety. Children with autism performed worse than the control children. In Experiment 2, 3 age groups (8-12 years, n = 49; 13-17 years, n = 49; and adults n = 45) were tested on the same stimuli. Whereas the performance of control individuals was best in the adult group, the performance of individuals with autism was similar in all age groups. Results are discussed with respect to underlying cognitive processes that may be affecting the development of emotion recognition in individuals with autism.

Do individuals with autism process categories differently? The effect of typicality and development.

This study examined the effect of exemplar typicality on reaction time and accuracy of categorization. High-functioning children (age 9-12), adolescents (age 13-16), and adults with autism (age 17-48) and matched controls were tested in a category verification procedure. All groups showed improved processing throughout the lifespan for typical and somewhat typical category exemplars. However, individuals with autism responded more slowly than matched controls to atypical exemplars at all ages. The results are discussed in terms of potential differences in the type of processing that may be required for categorizing typical and atypical category exemplars. Parallels are also drawn to the results of previous studies on face processing in individuals with autism.