Interpreting ambiguous stimuli: Separating perceptual and judgmental biases

Interpreting ambiguous situations is not a purely data-driven process but can be biased towards positive interpretations by top-down influences. The present study tries to identify the underlying processes of these top-down influences. There are two separable types of processes that can be influenced by motivational biases: A perceptual bias affects information uptake whereas a judgmental bias affects acceptance criteria for positive and negative outcomes. In the present study, motivated influences on perception and judgment were investigated with a simple color discrimination task in which ambiguous stimuli had to be classified according to their dominating color. One of two colors indicated a financial gain or a loss, whereas a third color was neutral. To separate perceptual and judgmental biases, Ratcliff's [Ratcliff, R. (1978). A theory of memory retrieval. Psychological Review, 85, 59-108] diffusion model was employed. Results revealed motivational influences on perception and judgment.