Refining the dual-stage account of intertrial feature priming: does motor response or response feature matter?

Numerous studies have shown that repetition of search-relevant attributes facilitates visual search performance. For example, Maljkovic and Nakayama (1994) showed that when observers search for a target defined by its color and report its shape, repetition of the target color speeds search, an effect known as priming of pop-out. While intertrial feature priming in search was initially thought to affect perceptual processes, the idea that it also affects postselection stages of processing is increasingly acknowledged. However, because in previous studies repetition of the motor response has typically been confounded with repetition of the response feature, it is not clear what mechanisms underlie the postselection effect of intertrial priming. In the present study, we dissociated the two repetition types. The results showed that repetition of the target-defining attribute from the previous trial affects selection of the motor response but not discrimination of the response attribute. The implications for current accounts of intertrial priming are discussed.