Abstract
Popular wisdom holds that two heads are better than one, but do two heads engaged in visual search produce a benefit beyond a linear combination of performance from two individuals? We applied Miller’s (1982) coactivation model to the analysis of search by pairs of participants. When this model is applied to an individual’s search for multiple targets, it predicts that responses to two redundant signals will be faster on average than responses to the faster single signal (i.e., coactivation will exceed the benefits of a race-horse model). Here we examined whether two individuals searching together would produce coactivation, or only horse-race, benefits. We compared individual (n=18) and collaborative (pairs=9) search in a task involving two possible targets at two possible spatial locations. During individual search, each participant was responsible for detecting a target regardless of its identity or location. During collaborative search, each pair was instructed to divide the task by either location ("find either of the two targets, but when they are on your side of the display") or target ("find only one of the two targets, but monitor both sides of the display"). Because visual space can be analyzed by an individual in parallel, whereas multiple targets must be compared serially (Houtkamp & Roelfsema, 2009), we expected to find more evidence for collaborative coactivation in the divided-target condition. The results confirmed our prediction: when pairs of participants divided the search task by location they demonstrated only horse-race benefits, although when they divided by target they exhibited collaborative coactivation. These findings indicate that coactivation models, previously used to understand measurable improvements in individual performance with multiple redundant signals, can be utilized to understand collaborative performance in tasks of joint cognition.
Meeting abstract presented at VSS 2012