[Affect and performance in simple problems].

We investigate the effects of emotional mood states on solving simple pattern comparison tasks. It is assumed that the effects of mood are mediated through response biases as well as effort expenditure. Departing from these assumptions, trend hypotheses are derived for the response biases evaluated by means of a signal detection analysis, for the response latencies, and for an adequate index of the underlying ability. The data support the hypotheses, and in particular, a positive mood state is found to improve performance. The assumption of mood-dependent differences in effort expenditure provides a parsimonious and integrative account of our results, while a reduced-capacity view cannot explain the findings obtained under positive mood induction.