Implicit and Explicit Learning of a Covariation Across Visual Search Displays

The goal of this study was to extend prior reports of implicit learning in visual search (e.g., Chun & Jiang, 1999) by employing eye movement monitoring and reaction time measures to contrast implicit and explicit learning. Towards this end, participants’ eye movements were monitored as they performed a visual search task in the ‘change blindness’ flicker paradigm. In each trial, participants were asked to detect a letter that differed in shape or color across otherwise identical alternating letter arrays. In a subset of trials, for some participants the background luminance covaried with target color (Color rule condition) and for other participants letter thickness covaried with target shape (Shape rule condition). In addition, half of the participants were told of the existence of a covariation (Informed group) and the other half were not notified of this regularity and in a post-experimental interview reported no awareness of this covariation (Uninformed group). In both groups, reaction time data indicated that visual search was facilitated for trials that contained the covariation, and eye movement data showed that participants guided eye movements to potential targets based on the covariation information. Further, Informed participants in the Color rule condition were able to use covariation information to a greater extent than those in the Shape rule condition. In contrast, no differential sensitivity across rule conditions was found for Uninformed participants. Implications to the study of implicit learning in visual search are discussed.