The interference of local over global information processing in children with attention deficit hyperactivity disorder of the inattentive type
ABSTRACT A classic finding in perception of compound patterns is normal individuals cannot skip global analysis in local-oriented processing, but they can successfully resist local analysis in global-oriented processing-the so-called global interference . Recently, studies examining the role of brain hemisphere activity in the Navon task have indicated that the processing of global and local information can be, respectively, attributed to the right and left hemispheres. Moreover, many neuroimaging researches have revealed that certain core symptoms of attention deficit hyperactivity disorder (ADHD) are related to dysfunction of right hemisphere. These findings imply that global interference will be substantially less evident, and possibly even replaced by local interference in ADHD. The present study compared the performance of children with and without attention deficit hyperactivity disorder of the inattentive type (ADHD-I) in the processing of global and local information to examine the local interference hypothesis in ADHD. An ADHD-I group (n=15) and a paired control group (n=19) completed tasks using two versions of the Navon task, one requiring divided attention, in which no information was given to participants regarding the level at which a target would appear, and the other requiring selective attention, in which participants were instructed to attend to either the local or the global level. The results showed that children with ADHD-I exhibited local interference, regardless of which attention procedure was used. These results support the weak right hemisphere hypothesis in ADHD, and provide evidence against the deficit hypotheses for ADHD in the DSM-IV criteria , which postulates that inattention symptoms may manifest as a failure to provide close attention to details.
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ABSTRACT: Background: "Global processing bias" is an automatic tendency to process the global picture prior to the local details. The right hemisphere is known to be more dominant in global processing, and some researchers have demonstrated its important role in alertness. Converging evidence implies some dysfunction in right hemisphere activation in people suffering from attention deficit hyperactivity disorder (ADHD). Global processing is yet to be understood in ADHD. Objective: We examined whether adults with ADHD show deficient global processing and whether this could be alleviated by the presence of an alerting signal. Method: Adult participants (20 ADHD, 20 typically developing controls) responded to a global-local Navon task in which they were asked to respond to the large stimulus or the small component stimuli, and to a Navon-like task with an alerting cue. Reaction time and accuracy were measured. Results: Unlike controls, adults with ADHD did not have global precedence; irrelevant global stimuli (when asked to respond to the local level) and irrelevant local stimuli (when asked to respond to the global level) produced similar interference in ADHD participants. Appearance of an alerting cue increased global processing bias (i.e., increased interference from global stimuli in the local block and reduced interference from local stimuli in the global block) for both groups, such that global processing in ADHD participants was comparable to that of controls. Conclusion: ADHD participants showed lack of a global processing bias. Most important, global processing bias was reinstated by an alerting cue. Implications for the definition of ADHD, which currently emphasizes failure to pay close attention to details, will be discussed. Moreover, the current results have important implications for social functioning of people suffering from ADHD. (PsycINFO Database Record (c) 2013 APA, all rights reserved).Neuropsychology 08/2013; 27(5). DOI:10.1037/a0033655 · 3.43 Impact Factor
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ABSTRACT: The purpose of this study was to assess the visual processing of global and local levels of hierarchical stimuli in domestic dogs. Fourteen dogs were trained to recognise a compound stimulus in a simultaneous conditioned discrimination procedure and were then tested for their local/global preference in a discrimination test. As a group, dogs showed a non-significant trend for global precedence, although large inter-individual variability was observed. Choices in the test were not affected by either dogs' sex or the type of stimulus used for training. However, the less time a dog took to complete the discrimination training phase, the higher the probability that it chose the global level of test stimulus. Moreover, dogs that showed a clear preference for the global level in the test were significantly less likely to show positional responses during discrimination training. These differences in the speed of acquisition and response patterns may reflect individual differences in the cognitive requirements during discrimination training. The individual variability in global/local precedence suggests that experience in using visual information may be more important than predisposition in determining global/local processing in dogs.Animal Cognition 12/2013; 17(4). DOI:10.1007/s10071-013-0720-1 · 2.63 Impact Factor