Abstract
Mounting evidence suggests that Inhibition of Return (IOR) can be elicited when one person is required to move to a target location recently acquired by a second person. These effects occur even when vision of the onset of that target is occluded, suggesting that observation of a second person's movement is sufficient to elicit the effect. One explanation for this effect (Welsh et.al, 2005, 2007) involves the activation of the mirror-neuron system during between-person trials serving to trigger the same inhibitory processes active during within-person trials. This study further explored this explanation by manipulating, not only vision of the between-person target location, but also the ability to physically interact with that location. It was hypothesized that if the mirror neuron system subserved between-person IOR, results would be consistent with Welsh et al (2005) when both vision of, and the ability to physically interact with, the second person's target is blocked. If, on the other hand, inhibition depends upon one's ability to physically interact with a target, between-person IOR effects would be eliminated when vision of the target location is available but the opportunity to physically interact with it is blocked (i.e., a see-through screen). Results suggest that while the opportunity to interact with a second person's target does not appreciably moderate between-person IOR, neither does the observation of another person's movement toward a specific location elicit it if the target is never in view. These findings are inconsistent with a strong mirror neuron explanation for between-person IOR.Acknowledgments: NSERC