1. the tendency for a study participant to give one answer or type of answer more than others, regardless of the stimulus condition. There are several different types of response bias, including the halo effect, nay-saying, and yea-saying. See also response set; response style.

2. in signal detection theory more specifically, the overall willingness to say yes (signal present) or no (signal not present), regardless of the actual presence or absence of the signal.