Biomedical subjects
U Frith
Publications and source records attributed to U Frith.
Why do autistic individuals show superior performance on the block design task?
Systematic variations of the block design task were given to 20 autistic, 33 normal and 12 mildly retarded subjects. Designs were contrasted which were either "whole" or segmented, rotated or unrotated, and which did or did not contain obliques. Only segmentation, but neither of the spatial orientation factors, revealed a significant group difference. Autistic subjects, regardless of age and ability, performed better than controls when presented with unsegmented designs. This result suggests that they need less of the normally required effort to segment a gestalt, and thus supports the hypothesis of weak central coherence as a characteristic of information processing in autism.
Deception and sabotage in autistic, retarded and normal children.
We investigated autistic, mentally retarded, and normal children's ability to deceive or obstruct an opponent. When required to tell a lie (saying that a box was locked) autistic children performed significantly worse than their controls, taking into account mental age. However, they readily prevented a competitor from gaining a reward by physical manipulation (locking a box). Their success on sabotage demonstrated that their failure on deception was not due to an inability to understand the task. Performance on deception was predicted by performance on a false belief attribution task. The present findings confirm that autistic children have a specific deficit in understanding and manipulating beliefs.
Can autism be predicted on the basis of infant screening tests?
The authors examined infant hearing and vision screening tests for a group of children subsequently diagnosed as autistic and compared them with a group of children suffering from non-specific developmental delay, as well as with a random sample of records. Four categories (motor, vision, hearing and language, social) were investigated at three ages: six, 12 and 18 months. The random sample group had a low incidence of reported problems at all ages. The learning-disabled group had a sharp increase in reported abnormalities in all categories at 12 months. The autistic group had a selective increase in the social category alone at 18 months.
The cognitive basis of a biological disorder: autism.
This article summarizes recent evidence indicating that individuals suffering from autism have a specific problem in understanding intentions and beliefs. We propose that this problem arises because they are incapable of forming a special kind of mental representation. A single cognitive deficit defines what is common to all autistic individuals. In contrast there is a wide range of proposals for the biological origins of the disorder.
Debate and argument: how useful is the "PDD" label?
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Autism is not necessarily a pervasive developmental disorder.
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Prospects for a cognitive neuropsychology of autism: Hobson's choice.
Leslie (1987b) proposed a new, metarepresentational model for the cognition of pretense. This model identified a cognitive component necessary for the normal development of a "theory of mind." In this article, the relation of the child's early affective sensitivities to this component is considered. Early affective sensitivities seem to be cognitively distinct from the metarepresentational component. Childhood autism provides an interesting opportunity to study this problem. Three theoretical possibilities for the pathogenesis of this condition are presented: (a) a basic affective disorder as proposed by Hobson (this issue, p. 114), (b) a basic affective disorder and a basic cognitive disorder jointly, and (c) a basic cognitive disorder. There is little evidence for Option a, and a growing body of evidence supports Option c. Option b is sidelined for the time being on grounds of parsimony. Leslie's original theoretical proposals are revised, and some resulting implications are presented for the future investigation of the cognitive neuropsychology of autism.
A new look at language and communication in autism.
In this review the specific language and communication impairments of autistic individuals are discussed and contrasted with non-specific impairments. All the impairments that are unique to autism concern the use of language for the purpose of intentional (but not instrumental) communication. The specific communication failure can be identified with a limitation in the computing of relevance and as a lack of taking account of mental states. This is a consequence of a subtle, but far-reaching, cognitive dysfunction. The dysfunction is likely to involve the formation and use of second-order representations. The same problem also leads to specific impairment in social relationships and imaginative play.
Exploration of the autistic child's theory of mind: knowledge, belief, and communication.
26 autistic children with mental ages of 3-13 years were tested on 3 tasks that are within the capability of 3- or 4-year-old normal children. The first task tested understanding of a mistaken belief. Children were shown a typical box of a certain brand of sweets, and they all thought that it contained that kind of sweet. To their surprise, however, the box contained something else. Yet, only 4 out of the 26 autistic children were able to anticipate that another child in the same situation would make the same mistake. In contrast, all but 1 of 12 children with specific language impairment, matched for mental age, understood that others would be as misled as they had been themselves. The autistic children were also tested for their ability to infer knowledge about the content of a container from having or not having looked inside. All 4 children who had passed the belief task and an additional 4 performed perfectly, but most failed. The third task assessed children's pragmatic ability to adjust their answers to provide new rather than repeat old information. Here, too, most autistic children seemed unable to reliably make the correct adjustment. These results confirm the hypothesis that autistic children have profound difficulty in taking account of mental states.
The understanding and use of interpersonal gestures by autistic and Down's syndrome children.
Autistic adolescents with mild, moderate, and severe degrees of mental retardation, Down's syndrome adolescents, and clinically normal 4-, 5-, and 6-year-old children were compared in their ability to understand a set of simple instrumental gestures. Almost all gestures were perfectly understood, that is, correctly responded to, by normal children from age 5 onwards, and by all the handicapped groups, regardless of diagnosis or degree of retardation. However, the ability to initiate such gestures on verbal request was generally less good, especially in the less able autistic groups. The same subjects were unobtrusively observed in the playground and during mealtime at their schools. Peer interactions were least frequent in the autistic subjects, regardless of degree of mental retardation. However, relative to interaction frequency, the autistic group used nonverbal instrumental gestures as a means of communication to the same extent as the other groups. Unlike Down's syndrome adolescents, or normal preschool children, no autistic adolescent ever used expressive gestures.
Metarepresentation and autism: how not to lose one's marbles.
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Comprehension in "hyperlexic" readers.
Mentally retarded children who can read aloud written words better than one would expect from their Mental Age are often called hyperlexic. The reading comprehension thought to be impaired in such children was investigated in four experiments. Mentally retarded advanced decoders, including autistic and nonautistic children, were compared with younger nonretarded children matched for Mental Age and Reading Age. Experiment 1 established that mildly mentally retarded readers could match sentences to pictures as well as could be expected from their verbal ability. This was the same whether they read the sentences or heard them. Experiment 2 demonstrated that only the more able retarded subjects, but not the less able ones, used sentence context in a normal way in order to pronounce homographs. Experiments 3 and 4 showed that these same more able children could extract meaning at both sentence and story level, and their performance was indistinguishable from that of normal controls. Hence, it is doubtful whether these advanced decoders should be called hyperlexic. In contrast, the readers of relatively low verbal ability performed much worse than their normal controls. Although they could be induced under certain conditions to read sentence-by-sentence rather than word-by-word, they did not do so spontaneously. Furthermore, they did not make use of already existing general knowledge in order to answer questions about the stories they had read. The ability to comprehend in terms of large units of meaning seems to be specifically impaired in these low verbal ability fluent readers. We suggest that it is this impairment that marks true hyperlexia. Since there were no differences between autistic and nonautistic readers on any of our tasks, we conclude that hyperlexia is not an autism-specific phenomenon.
Does the autistic child have a "theory of mind"?
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An islet of ability in autistic children: a research note.
An aspect of cognitive functioning in autistic children was investigated by comparing their performance on the Children's Embedded Figures Test with that of MA-matched normal and MA- and CA-matched mentally retarded non-autistic children. The autistic children were significantly more competent at this task than either group of control children, and also showed qualitatively different strategies. Since the performance of the autistic children was better than predicted from MA and commensurate with CA, it can be regarded as an islet of ability. This finding is discussed in terms of orientation and visualization factors involved in visuo-spatial abilities and is also related to cognitive deficit.
Experimental approaches to developmental dyslexia: an introduction.
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The motor deficit in Down's syndrome children: a problem of timing?
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