Freely selected and forced responses quickly bind to the target location, but not to the target identity, that activates them in a visuo-spatial task


Target objects are identified by analyzing their features (i.e., colour, shape, size, etc.) separately and automatically; hence, post-identification, must later bind together to form a comprehensive object. This study looked into whether target identities and/or locations bind to their assigned responses. Subjects experienced a visuo-spatial task involving paired sequential trials; first the 'prime' and then the 'probe'. Correct manual responses were determined by target location, some locations allowing for a 'free choice' of two permissible outputs, while other locations required a 'forced choice' response. Critical free choice trials involved a competition between a former prime target response and a control response, and involved between-hand or within-hand finger responses. Targets appeared randomly at 'free choice' and 'forced choice' locations. When the prime target's location was repeated on the probe, subjects showed a significant bias toward choosing the just-executed prime response, indicating that self-selected prime trial responses strongly bind to the target-occupied locations generating their execution; however, they did not bind to the target's identity. In this way, freely chosen prime responses behaved like responses that are predetermined (Hommel, 2007) by the prime target; binding to relevant (location), but not to irrelevant, target properties (Hommel, 2004). When the prime-probe target location changed, the free choice bias reversed; subjects preferred the control response, presumably because this avoided a location-response binding violation. Longer latencies for the just-executed versus the control responses supported a violation aversion selection force.

Acknowledgments: This work was supported by a grant from the Natural Sciences and Engineering Research Council of Canada to the second author.