Biomedical subjects

Simon A Moss

Publications and source records attributed to Simon A Moss.

7 recordsLinked to original sources

PubMed2006

Pseudo-random number generation in children with high-functioning autism and Asperger's disorder: further evidence for a dissociation in executive functioning?

The repetitive, stereotyped and obsessive behaviours, which are core diagnostic features of autism, are thought to be underpinned by executive dysfunction. This study examined executive impairment in individuals with autism and Asperger's disorder using a verbal equivalent of an established pseudo-random number generating task. Different patterns of disinhibition emerged in the autism (n = 12) and Asperger's disorder (n = 12) groups. Consistent with previous research, the autism group repeated single numbers (e.g. 2, 2, 2) more frequently than the control group. In contrast to past research suggesting intact executive abilities, this study found that the Asperger's disorder group generated more repetitive number patterns (e.g. 45, 45) than the controls. Executive functioning in children with Asperger's disorder may be particularly vulnerable to a lack of visual cueing and concrete rules. Qualitative differences in executive dysfunction between these groups may implicate differential disruption within the fronto-striatal circuitry.

Asperger Syndrome↗

PubMed2005

Does selective attention influence the octave illusion?

The octave illusion occurs when each ear receives a sequence of tones alternating by one octave, but with different frequencies in each ear. Most listeners report a high pitch in one ear alternating with a low pitch in the opposite ear. Deutsch and Roll proposed an influential suppression model of the illusion in which the pitch is determined by ear dominance, while the location of this pitch is determined by high-frequency dominance. Deutsch later suggested that this unusual division between 'what' and 'where' mechanisms is facilitated by sequential interactions within the eliciting sequence. A recent study has raised doubts about the suppression model and the role of sequential interactions in the illusion (Chambers et al, 2002 Journal of Experimental Psychology: Human Perception and Performance 28 1288-1302). Here, we examined whether this previous null effect of sequential interactions may have arisen because of uncontrolled influences of selective attention. The results reveal no evidence of a link between selective attention and sequential interactions, thus consolidating doubts about the validity of the suppression model.

Acoustic Stimulation↗

PubMed2004

A unique look at face processing: the impact of masked faces on the processing of facial features.

This experiment utilized a masked priming paradigm to explore the early processes involved in face recognition. The first experiment investigated implicit processing of the eyes and mouth in an upright face, using prime durations of 33 and 50 ms. The results demonstrate implicit processing of both the eyes and mouth, and support the configural processing theory of face processing. The second experiment used the same method with inverted faces and the third experiment was a combination of Experiments 1 and 2. The fourth experiment utilized misaligned faces as the primes. Based on the pattern of results from these experiments, we suggest that, when a face is inverted, the eyes and mouth are initially processed individually and are not linked until a later stage of processing. An upright face is proposed to be processed by analysis of its configuration, whereas an inverted face is initially processed using first-order relational information, and then converted to an upright representation and transferred to face specific regions for configural analysis.

Adult↗

PubMed2004

Impact of child sexual abuse on mental health: prospective study in males and females.

BACKGROUND: The lack of prospective studies and data on male victims leaves major questions regarding associations between child sexual abuse and subsequent psychopathology. AIMS: To examine the association between child sexual abuse in both boys and girls and subsequent treatment for mental disorder using a prospective cohort design. METHOD: Children (n=1612; 1327 female) ascertained as sexually abused at the time had their histories of mental health treatment established by data linkage and compared with the general population of the same age over a specified period. RESULTS: Both male and female victims of abuse had significantly higher rates of psychiatric treatment during the study period than general population controls (12.4% v. 3.6%). Rates were higher for childhood mental disorders, personality disorders, anxiety disorders and major affective disorders, but not for schizophrenia. Male victims were significantly more likely to have had treatment than females (22.8% v.10.2%). CONCLUSIONS: This prospective study demonstrates an association between child sexual abuse validated at the time and a subsequent increase in rates of childhood and adult mental disorders.

Adolescent↗

PubMed2004

Reconsidering evidence for the suppression model of the octave illusion.

The octave illusion is elicited by a sequence of tones presented to each ear that continuously alternate in frequency by one octave, but with high and low frequencies always in different ears. The percept for most listeners is a high pitch in one ear, alternating with a low pitch in the other ear. The influential suppression model of the illusion proposed by Deutsch and Roll (1976) carries three postulates: first, that listeners perceive only the pitch of the tones presented to their dominant ear; second, that this pitch is heard in whichever ear received the higher frequency tone; and third, that this apparent dissociation between what and where mechanisms arises from sequential interactions between the tones. In the present article, we reappraise evidence for the suppression model and demonstrate (1) the incompatibility of the theory with the existing literature on pitch perception, sound localization, and ear dominance and (2) methodological limitations in studies that have claimed to provide support for the suppression model. We conclude by proposing an alternative theory of the octave illusion that is based on established principles of fusion, rather than suppression, between ears.

Auditory Perception↗

PubMed2002

Random number generation in autism.

This study explored the ability of individuals with autism to generate a unique series of digits. Fourteen low-functioning individuals with autism, 14 intellectually disabled individuals, and 14 postgraduate university students generated a series of pseudo-random digits. Individuals with autism were more likely to repeat previous digits than were either of the control groups. The normal control group, however, was less likely to attempt cycling through all digits before repeating. Accordingly, low-functioning individuals with autism may exhibit a short-fall in response inhibition. This finding supports the executive dysfunction theory of autism.

Adolescent↗

PubMed2002

The octave illusion revisited: suppression or fusion between ears?

The octave illusion occurs when each ear receives a sequence of tones alternating by 1 octave but with the high and low tones in different ears. Most listeners perceive these stimuli as a high pitch in one ear alternating with a low pitch in the other ear. D. Deutsch and P. L. Roll (1976) interpreted this phenomenon as evidence for a what-where division of auditory processing caused by sequential interactions between the tones. They argued that the pitch follows the frequency presented to the dominant ear but is lateralized toward the higher frequency component. This model was examined in 4 experiments. Results indicate that the perceived pitch approximates the fundamental frequency and that the illusion does not depend on sequential interactions. The octave illusion may arise from an interaction between dichotic fusion and binaural diplacusis rather than from suppression as proposed by Deutsch.

Adolescent↗