Objectives: To examine hierarchical visuospatial processing in children with neurofibromatosis type 1 (NF1), a single gene disorder associated with visuospatial impairments, attention deficits, and executive dysfunction. Methods: We used a modified Navon paradigm consisting of a large “global” shape composed of smaller “local” shapes that were either congruent (same) or incongruent (different) to the global shape. Participants were instructed to name either the global or local shape within a block. Reaction times, interference ratios, and error rates of children with NF1 (n=30) and typically developing controls (n=24) were compared. Results: Typically developing participants demonstrated the expected global processing bias evidenced by a vulnerability to global interference when naming local stimuli without a cost of congruence when naming global stimuli. NF1 participants, however, experienced significant interference from the unattended level when naming both local and global levels of the stimuli. Conclusions: Findings suggest that children with NF1 do not demonstrate the typical human bias of processing visual information from a global perspective. (JINS, 2017, 23, 446–450)

The present study examined whether patients with obsessive-compulsive disorder (OCD) focus on details at the expense of global aspects. A recent study of our group using Navon letters (e.g., the letter “S” composed out of “A” letters) did not yield differences between OCD patients and controls on local processing. However, the task used may have lacked sensitivity, because it did not involve a response conflict condition (i.e., global and local level associated with different responses). In the current study, we gradually varied between-level conflict. Twenty-eight OCD patients and 30 healthy controls had to attend to the global and the local level of each item. OCD patients displayed comparable performance: Patients neither displayed a preference to respond to the local level nor enhanced interference from the local level. In conclusion, the present study does not support the idea that a generalized bias to “miss the forest for the trees” forms part of the vulnerability to OCD. (JINS, 2008, 14, 489–493.)

Research conducted with the Rey-figure task has suggested that patients with obsessive-compulsive disorder (OCD) process local aspects of a complex stimulus more efficiently than the overall gestalt. The aim of the present study was to investigate if this “local bias” is established already during early stimulus encoding or occurs only during later processing, once a percept has been formed (e.g., memory retrieval). To this end, responding to local and global targets of hierarchical letters (e.g., an “E” composed out of small “T”s) was assessed in 30 OCD patients and 28 healthy controls. OCD patients and controls performed comparably on all parameters. These results lend no support to the notion of an early perceptual bias towards local elements in OCD patients. It remains to be tested whether a bias towards local features is confined to situations where local and global features compete for selection. (JINS, 2006, 12, 566–569.)

This study explored the claim that individuals with autism and Asperger's disorder tend to process locally rather than holistically. Participants observed a large or “global” number composed of smaller or “local” numbers. The response was contingent upon the identification of either the large stimulus or the small stimuli. Relative to age, sex, and IQ matched controls, global processing in children and adolescents with autism (N = 12) and Asperger's disorder (N = 12) was more vulnerable when the local stimuli were incongruent. The autism group made more global errors than their matched control group, regardless of whether there was local incongruence. In contrast, the Asperger's disorder group made a similar number of global errors as their respective control group. These results were discussed in relation to an “absence of global precedence” notion, “weak central coherence” theory, and right-hemisphere dysfunction. The neurobiological significance of these findings were discussed in the context of a fronto-striatal model of dysfunction.

Two tasks were used to assess the processing of whole versus parts of objects in a group of high-functioning children and adolescents with autism (N=11) and a comparison group of typically developing peers (N=11) matched for chronological age and IQ. In the first task, only the children with autism showed a global advantage, and the two groups showed similar interference between levels. In the second task, the children with autism, despite longer RTs, showed similar performance to the comparison group with regard to the effect of goodness on visual parsing. Contrary to expectations based on the central coherence and hierarchisation deficit theories, these findings indicate intact holistic processing among persons with autism. The implications of these findings are discussed in relation to apparently discrepant evidence from other studies.