Effects of saliency, not global dominance, in patients with left parietal damage

Carmel Mevorach*, Glyn W. Humphreys, Lilach Shalev

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

Neuropsychological and functional imaging studies have shown a general right hemisphere advantage for processing global visual information and a left hemisphere advantage for processing local information. There is also evidence for the left parietal lobe being important for switching attention between local and global levels. Here we examined whether the left parietal lobe is associated with another aspect of attentional control over hierarchical visual processing; namely, ignoring the irrelevant aspect of the stimulus when it is more salient than the target attribute. In experiment 1 a group of left parietal patients were abnormally affected by a salient local stimulus that significantly interfered with their ability to identify global shapes. This effect was reversed in experiment 2 when small sized compound letters were used (where the global shape was more salient than the local letters). The patients then had difficulty ignoring the global shape. Experiments 3 and 4 demonstrated that the failure to accurately identify global form in experiment 1 could not be attributed to a difficulty in spreading attention across a large area. Finally, in experiment 4 the effect of a salient irrelevant stimulus was significantly attenuated when the irrelevant level did not map onto a response. The data indicate that damage to the left parietal lobe disrupts the ability to select attributes of stimuli that have low salience when other attributes have high salience for the task.

Original languageEnglish
Pages (from-to)307-319
Number of pages13
JournalNeuropsychologia
Volume44
Issue number2
DOIs
StatePublished - 2006
Externally publishedYes

Funding

FundersFunder number
Anglo Israel Association
Medical Research Council
Stroke Association

    Keywords

    • Attentional control
    • Global/local processing
    • Response selection
    • Stimulus selection

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