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Background Traits and characteristics qualitatively similar to those seen in diagnosed autism spectrum disorder can be found to varying degrees in the general population. To measure these traits and facilitate their use in autism research, several questionnaires have been developed that provide broad measures of autistic traits [e.g. Autism-Spectrum Quotient (AQ), Broad Autism Phenotype Questionnaire (BAPQ)]. However, since their development, our understanding of autism has grown considerably, and it is arguable that existing measures do not provide an ideal representation of the trait dimensions currently associated with autism. Our aim was to create a new measure of autistic traits that reflects our current understanding of autism, the Comprehensive Autism Trait Inventory (CATI). Methods In Study 1, 107 pilot items were administered to 1119 individuals in the general population and exploratory factor analysis of responses used to create the 42-item CATI comprising six subscales: Social Interactions, Communication, Social Camouflage, Repetitive Behaviours, Cognitive Rigidity, and Sensory Sensitivity. In Study 2, the CATI was administered to 1068 new individuals and confirmatory factor analysis used to verify the factor structure. The AQ and BAPQ were administered to validate the CATI, and additional autistic participants were recruited to compare the predictive ability of the measures. In Study 3, to validate the CATI subscales, the CATI was administered to 195 new individuals along with existing valid measures qualitatively similar to each CATI subscale. Results The CATI showed convergent validity at both the total-scale (r ≥ .79) and subscale level (r ≥ .68). The CATI also showed superior internal reliability for total-scale scores (α = .95) relative to the AQ (α = .90) and BAPQ (α = .94), consistently high reliability for subscales (α > .81), greater predictive ability for classifying autism (Youden’s Index = .62 vs .56–.59), and demonstrated measurement invariance for sex. Limitations Analyses of predictive ability for classifying autism depended upon self-reported diagnosis or identification of autism. The autistic sample was not large enough to test measurement invariance of autism diagnosis. Conclusions The CATI is a reliable and economical new measure that provides observations across a wide range of trait dimensions associated with autism, potentially precluding the need to administer multiple measures, and to our knowledge, the CATI is also the first broad measure of autistic traits to have dedicated subscales for social camouflage and sensory sensitivity.

Individuals diagnosed with autistic spectrum conditions often show deficits in processing emotional faces relative to neurotypical peers. However, little is known about whether similar deficits exist in neurotypical individuals who show high-levels of autistic-like traits. To address this question, we compared performance on an attentional blink task in a large sample of adults who showed low- or high-levels of autistic-like traits on the Autism Spectrum Quotient. We found that threatening faces inserted as the second target in a rapid serial visual presentation were identified more accurately among individuals with low- compared to high-levels of autistic-like traits. This is the first study to show that attentional blink abnormalities seen in autism extend to the neurotypical population with autistic-like traits, adding to the growing body of research suggesting that autistic-related patterns of behaviors extend into a subset of the neurotypical population. Autism Res 2017, 10: 311-320. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

Individuals with autism spectrum conditions attend less to the left side of centrally presented face stimuli compared to neurotypical individuals, suggesting a reduction in right hemisphere activation. We examined whether a similar bias exists for non-facial stimuli in a large sample of neurotypical adults rated above-or belowaverage on the autism spectrum quotient (AQ). Using the ''greyscales'' task, we found the typical leftward bias in the below-average group was significantly reduced in the above-average group. Moreover, a negative correlation between leftward bias and the social skills factor of the AQ suggested a link between atypical hemispheric activation and social difficulties in high-AQ trait individuals that extends to non-facial stimuli.

Although repetition is generally assumed to enhance the accessibility of memory for rehearsed material, recent research has suggested that prolonged repetition might actually be detrimental under some conditions. In the present work, we manipulated repetition duration and learning condition (intentional vs. incidental) in an effort to clarify the relationship between repetition and memory. Replicating previous findings, memory for repeated items declined with increased repetition under incidental-learning conditions. However, increased repetition had the opposite effect under intentional-learning conditions. Taken together, these results provide evidence for distinctive mechanisms of memory acquisition during repetition that vary depending on learning context.