[Effects of natural mood changes on discrimination performance and response trends in pattern recognition].

The effects of mood on thinking and behavior are characterized by "loosening" in the case of positive feeling states and "tightening" for negative ones (Fiedler, 1988). Style of cognitive processing, effort expenditure, and capacity models are discussed as explanatory concepts. To compare these approaches, the theory of signal detection provides methods for the independent evaluation of parameters of response bias and discrimination (and also efficiency). A laboratory experiment (Klauer et al., 1991) was replicated and supplemented by a field study. In the sense of convergent and discriminant validation of the insufficient techniques of mood induction, the naturally occurring mood changes of everyday life were used as mood manipulations. 13 subjects (M = 25.9 years of age, SD = 3.8) reported their feeling states on 18 days for self-selected episodes, which represented the range of their mood changes. Immediately after each mood report, they worked on a visual discrimination task. The indices of signal detection theory for response bias, discrimination, and efficiency were calculated in each cases, and correlated with measures of emotional and unspecific feeling states. Along with a shift from negative to positive feeling states, a trend towards a liberal response bias, a higher discrimination rate, and a greater efficiency resulted. Our findings replicate the laboratory experiment and support the effort expenditure and cognitive processing style view, rather than the reduced-capacity explanation. Speculations are offered concerning the emotional and cognitive processes which led to these results.