Self-initiated encoding facilitates object working memory in schizophrenia: implications for the etiology of working memory deficit.
BACKGROUND
Working memory (WM) deficit is present in a majority of patients with schizophrenia but it is unclear which components of WM are impaired. Past studies suggest that encoding may be compromised. One important determinant of encoding is the deployment of selective attention to the target stimulus. In addition, attention and encoding are modulated by motivational factors. In this study, we investigated the effects of self-initiated encoding (i.e., voluntary attention) on WM.


METHODS
19 patients with schizophrenia and 19 matched control subjects participated in visual WM and control tasks. Encoding was manipulated by asking subjects to select from two face targets and memorize 1) one of the two identical faces (Non-preference condition), 2) one that is marked (Non-choice condition), and 3) one they prefer (Preference condition). WM accuracy for both location (spatial) and identity (object) was measured.


RESULTS
Overall, patients with schizophrenia were less accurate and slower than the control subjects but the deficit was greater for object WM. However, patients were more accurate in object WM when they selected a preferred face as their target during encoding (preference condition) compared with the other two conditions. This effect was not significant for spatial WM.


CONCLUSIONS
These results suggest that voluntary, self-initiated attention may facilitate object encoding especially if the selection of the target involves affective choice, and that attention may play different roles in encoding 'what' versus 'where' in WM. Since encoding affects all forms of memory, these results may have a more general implication for memory.
Kim
Jejoong
J
Department of Psychology, Vanderbilt University, 111 21st Ave South, TN 37240, USA.
Park
Sohee
S
Shin
Yong-Wook
YW
Jin Lee
Kyung
K
Kwon
Jun Soo
JS
D000328:Adult; D001288:Attention; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy*; D009483:Neuropsychological Tests; D011930:Reaction Time; D012559:Schizophrenia / Q000150:complications*; D020377:Self Efficacy; D012932:Social Facilitation