Attentional capture in schizophrenia and schizotypy: effect of attentional load

We examined the effect of attentional load on attentional capture in schizophrenia. On the basis of the ''resource limitations hypothesis'' in schizophrenia, we propose that attentional capture by an irrelevant distractor will be differentially affected by the attentional load for patients and healthy controls.

70 patients with schizophrenia, 15 schizotypals, and 54 controls were asked to attend to a central task while a lateral distractor moved. Participants were instructed either (i) to localise a black square (low-load condition), or (ii) to locate the larger number between two 1-digit numbers (medium-load condition), or (iii) to locate the larger number between two several-digit numbers (high-load condition). In the baseline condition, no distractor moved.

All groups showed attentional capture in the low-load condition. Patients and schizotypals resisted interference from the distractor in the medium and highload conditions. Controls resisted interference in the high-load condition.

The results suggest that attentional modulation is impaired in schizophrenia and in the schizophrenia spectrum.