Distractibility is Reflected in the Structure and Function of the Parietal Cortex
Sustaining attention and blocking goal-irrelevant information is a crucial function in everyday life. Kanai and colleagues combining neuroimaging, self-report judgements and TMS found evidence that indicates that a region of the left superior parietal cortex mediates this function.
The ability to avoid distractibility varies across individuals as measured by the Cognitive Failures Questionnaire (CFQ) (Broadbent et al., 1982). Studies on twins and families have showed that the ability to maintain attention in the presence of distractors is highly heritable (Boomsma, 1998). High degree of heritability suggests that the variability might be mediated by genetic influences on the brain, which may be expressed via variability in brain structure.
This hypothesis was tested by Kanai et al. by scanning 145 healthy adult individuals and obtaining their CFQ scores. They used voxel-based morphometry (VBM) to examine whether distractibility scores predicted brain structure. Their results revealed that the level of an individual’s distractibility in everyday life was predicted by variability in regional grey matter density of the left superior parietal lobe (SPL). Highly distractable individuals had larger grey matter density at the left SPL. This particular region has been implicated in top-down attentional control in previous studies (Mevorach et al., 2009). To examine whether there is a causal relationship between this region and distractibility, Kanai et al. applied transcranial magnetic stimulation (TMS) over the left SPL of the participants while they were performing an attentional capture paradigm. The results of the experiment suggest that the left SPL plays a role in suppressing distraction from task-irrelevant salient distractors in both visual fields.
Kanai R, Dong MY, Bahrami B, & Rees G (2011). Distractibility in daily life is reflected in the structure and function of human parietal cortex. The Journal of neuroscience : the official journal of the Society for Neuroscience, 31 (18), 6620-6 PMID: 21543590
Boomsma, D. I. (1998). Genetic analysis of cognitive failures (CFQ): a study of dutch adolescent twins and their parents. Eur. J. Pers., 12(5):321-330.
Broadbent, D. E., Cooper, P. F., FitzGerald, P., and Parkes, K. R. (1982). The cognitive failures questionnaire (CFQ) and its correlates. The British journal of clinical psychology / the British Psychological Society, 21 (Pt 1):1-16.
Mevorach, C., Shalev, L., Allen, H. A., and Humphreys, G. W. (2009). The left intraparietal sulcus modulates the selection of low salient stimuli. Journal of cognitive neuroscience, 21(2):303-315.