Sensorimotor skills and language comprehension in autistic children

The objectives of this study were to examine the level of sensorimotor concepts of young autistic children and to relate these concepts to language comprehension. A sample of 16 autistic children with a mean mental age of 24.8 months was administered a standardized scale of sensorimotor intelligence and of receptive language. The autistic children demonstrated surprisingly sophisticated sensorimotor skills, particularly object permanence. While their initial performance was inferior to that of normal controls matched on mental age, particularly in their use of objects in combination, the difference between groups diminished on the second test administration. On the receptive language measure, the autistic children were less able to identify words correctly. The sensorimotor behavior of autistic children who demonstrated language comprehension did not differ from those who showed no language comprehension, except that the former group tended to use an object as an instrument somewhat more frequently. The fact that the autistic children were so impaired in language even with fairly good sensorimotor skills suggests that these skills, particularly object permanence, play a minor role in their language acquisition.Support for this research was provided by Biobehavioral Research Support Grant 516, Grant 12–41 from the March of Dimes, NIMH Postdoctoral Fellowship No. 1 F32 MH07550-01 (Ungerer), and NIMH Grant MH 33815-01. Subjects were recruited from the UCLA Research Center for the Study of Childhood Psychosis, funded by NIMH Grant MH 30897. We would like to thank members of the CRC, particularly Dr. Peter Tanguay, Dr. Barbara Fish, and Dr. B. J. Freeman, for their support of our research efforts.     

Modeling longitudinal change in the language abilities of children with autism: parent behaviors and child characteristics as predictors of change

The objective of the current study was to evaluate the patterns of longitudinal change in the language abilities of 28 children with autism during early and middle childhood. Results from fitting a series of multilevel models showed that children's rate of language growth was independently predicted by (a) children's responsiveness to others' bids for joint attention and (b) parents' responsiveness to their children's attention and activity during play. Both predictive relations could not be explained by initial variation in global developmental characteristics, such as IQ, mental age, or language abilities. These findings support a social?pragmatic view on language acquisition, which emphasizes the collaborative process through which children and their parents negotiate shared meaning.     

Effects of practice on task architecture: combined evidence from interference experiments and random-walk models of decision making

Does extensive practice reduce or eliminate central interference in dual-task processing? We explored the reorganization of task architecture with practice by combining interference analysis (delays in dual-task experiment) and random-walk models of decision making (measuring the decision and non-decision contributions to RT). The main delay observed in the Psychologically Refractory Period at short stimulus onset asynchronies (SOA) values was largely unaffected by training. However, the range of SOAs over which this interference regime held diminished with learning. This was consistent with an overall shift observed in single-task performance from a highly variable decision time to a reliable (non-decision time) contribution to response time. Executive components involved in coordinating dual-task performance decreased (and became more stable) after extensive practice. The results suggest that extensive practice reduces the duration of central decision stages, but that the qualitative property of central seriality remains a structural invariant.     

The cost of serially chaining two cognitive operations

As Turing (1936, Proceedings of the London Mathematical Society) noted, a fundamental process in human cognition is to effect chained sequential operations in which the second operation requires an input from the preceding one. Although a great deal is known about the costs associated with 'independent' (unrelated) operations, e.g., from the classic psychological refractory period paradigm, far less is known about those operations to which Turing referred. We present the results of two behavioural experiments, where participants were required to perform two speeded sequential tasks that were either chained or independent. Both experiments reveal the reaction time cost of chaining, over and above classical dual-task serial costs. Moreover, the chaining operation significantly altered the distribution of reaction times relative to the Independent condition in terms of an increased mean and variance. These results are discussed in terms of the cognitive architecture underlying the serial chaining of cognitive operations.     

Sensorimotor synchronization: neurophysiological markers of the asynchrony in a finger-tapping task

Psychological Research - Sensorimotor synchronization (SMS) is a form of referential behavior in which an action is coordinated with a predictable external stimulus. The neural bases of the...