Psychometric functions for hybrid difference discrimination/increment detection tasks.

Psychometric functions collected from difference discrimination tasks typically have slopes near 1, whereas those from increment detection tasks have slopes near 2. Experiments exploring the effect of stimulus configuration on the psychometric function were undertaken. Some stimuli were configured to conform to difference discrimination and increment detection tasks, while other "hybrid" stimulus configurations had physical properties associated with both tasks. The results suggest that these hybrid configurations may have psychophysical properties that fall in between those found for difference discrimination and increment detection tasks.