Nat Precedings080208.rtf

A number of investigators have found perceptual deficits in schizophrenic subjects. It has also been indicated that those with schizophrenia suffer from reduced attention. This raises the possibility that their perceptual deficits may wholly or in part reflect attentional effects. The present study used computer simulations to examine the potential effects of inattention on performance measures determined with three psychophysical methods: the Two Alternative Forced Choice (2-AFC) Staircase Method, the Two Alternative Forced Choice (2-AFC) Fixed Stimuli Method, and the Yes/No Method. It is shown that both 2-AFC methods are susceptible to attentional effects but, in contrast, the Yes/No Method may allow for the differentiation of attentional effects from sensory sensitivity and subjective criterion effects. The simulations indicate that it may be possible to control for attention effects by using Yes/No Method in combination to a 2AFC method. Key words; Attention; schizophrenia; vision; psychophysics; 2-AFC methods; Yes/No methods. N at ur e P re ce di ng s : d oi :1 0. 10 38 /n pr e. 20 08 .1 58 4. 1 : P os te d 9 F eb 2 00 8