The level and nature of autistic intelligence III: Inspection time.

Abstract

Across the autism spectrum, level of intelligence is highly dependent on the psychometric instrument used for assessment, and there are conflicting views concerning which measures best estimate autistic cognitive abilities. Inspection time is a processing speed measure associated with general intelligence in typical individuals. We therefore investigated autism spectrum performance on inspection time in relation to two different general intelligence tests. Autism spectrum individuals were divided into autistic and Asperger subgroups according to speech development history. Compared to a typical control group, mean inspection time for the autistic subgroup but not the Asperger subgroup was significantly shorter (by 31%). However, the shorter mean autistic inspection time was evident only when groups were matched on Wechsler IQ and disappeared when they were matched using Raven's Progressive Matrices. When autism spectrum abilities are compared to typical abilities, results may be influenced by speech development history as well as by the instrument used for intelligence matching.

Does WISC-IV Underestimate the Intelligence of Autistic Children?

“…Autistic children achieved significantly higher RPM than WISC-IV full-scale scores, a discrepancy not found in typical control children. This result is consistent with and adds to previous findings (e.g., Barbeau et al 2013, which includes an overview) suggesting that RPM may better represent autistic intelligence than does Wechsler scales.…”

“…This does not, however, necessarily hold true for adults or children on the autism spectrum, whose RPM scores have been reported as significantly, and sometimes dramatically, higher than their Wechsler fullscale IQ (FSIQ) (Barbeau et al 2013;Bölte et al 2009;Dawson et al 2007;Hayashi et al 2008;Soulieres et al 2009), including in a large population-based sample (Charman et al 2011). Autistics' Wechsler Verbal and Performance IQ (VIQ and PIQ) may, in addition, be significantly lower than their RPM scores (e.g., Dawson et al 2007).…”

“…Previous research found different patterns of cognitive abilities in autism spectrum individuals subgrouped according to speech development anomalies (i.e., in autistic vs. Asperger subgroups) (Barbeau et al 2013;Soulières et al 2011). For this reason, and for comparability with previous studies, we chose to limit this study to autism spectrum children characterized by speech delays and/or other speech development anomalies.…”

Visuo-Spatial Performance in Autism: A Meta-analysis

“…Many of the reviewed studies used a mixed sample of individuals with autism, AS and HFA, a distinction no longer made (American Psychiatric Association 2013), and it may be that such differences contribute to the observed heterogeneity. Barbeau et al (2013) advise that perceptual peaks may disappear according to matching decisions. Matching is commonly done on the basis of age, gender, and IQ (performance IQ, verbal IQ, or full scale IQ).…”

Mental imagery scanning in autism spectrum disorder

“…This has positive implications for the development of training interventions that utilise external representational aids such as maps in order to foster survey-based navigational strategies in ASD. The different patterns of IQ and working memory correlations with task performance in ASD furthers the notion that individuals with the disorder may go through rather different underlying cognitive processes when performing cognitive tasks (e.g., Barbeau, Souliè res, Dawson, Zeffiro, & Mottron, 2013). Specifically, ASD participants in the present study appeared to rely more on verbal strategies and working memory to scan their mental images.…”