Reducing the saliency of intentional stimuli results in greater contextual-dependent performance

Wright and Shea (1991) described intentional stimuli as explicitly identifi ed information necessary to successfully perform a task, whereas incidental stimuli are not explicitly identified as crucial to task performance but h ave the potential to become associated with particular responses because of their selective presence in the training environment. Shea and Wright (199 5), using a speeded-choice RT task, indicated that manipulating the strengt h of association between incidental information and the responses, by chang ing the discriminibility of incidental stimuli while fixing the strength of the association between the intentional stimuli and each response, had a s ignificant impact on task performance. The present experiment further exami ned the role played by incidential stimuli when the strength of association between the intentional stimuli and the associated responses was reduced, by minimising stimulus-response compatibility. It was assumed that this lat ter manipulation would have a similar impact as increasing the strength of incidential stimuli-response relationships. That is, the relative contribut ion of the incidental stimuli would increase, resulting in an increase in c ontest-dependent behaviour during tests in which the intentional and incide ntal stimuli activated different responses. The results were in agreement w ith this prediction and consistent with a model For contextual-dependent pe rformance proposed by Shea and Wright (1995) as well as with the outshining hypothesis forwarded by Smith (1988, 1994).