Exogenous cues make search less effortful

In visual search, a cue predicting the location of an upcoming target facilitates the speed of target report, with the benefit of the cue being proportional to its predictive validity. Although behavioral data supports the facilitation of search performance by a predictive cue, it is unclear whether validly cuing the target location can reduce the mental effort involved in searching for the target. In the current experiment, participants searched for a target among distractors and identified whether the target had a gap on the left or the right. Each trial was preceded by an exogenous cue that could appear at the location of one of the items. Participants completed three types of blocks where the cue validity was initially set to 25%, 45%, or 65%. After the initial validity was indicated, participants were given the option to use a hand dynamometer to exert physical effort to increase the cue validity up to 85%. The duration of each trial was fixed at three seconds using a dynamic inter-trial-interval, and participants were explicitly informed that there was nothing they could do to shorten the duration of the experiment. We observed a robust validity effect for the exogenous cue in both response time and accuracy, indicating that participants used the cue to help localize the target. Participants were also strongly motivated to increase cue validity, exerting near-ceiling levels of force regardless of block type. That is, regardless of how high the validity of the cue was initially set to, participants were willing to exert their maximal physical effort to bring validity up to 85%. Our findings suggest that validly cuing the target location reduces the mental effort of searching, to the degree that participants are willing to trade off some measure of physical effort in order to achieve this reduction in mental effort.