Riggio, L. 1 , Marino, B. F. 1 & Mussi, D. R. 2
1 Dipartimento di Neuroscienze, Università di Parma, Parma, Italy
2 Dipartimento di Psicologia, Università di Parma, Parma, Italy
It has been shown that inhibition of return (IOR) amplifies the Simon effect. In the present study we tested whether IOR may also modulate the social Simon effect, recently observed by distributing the standard Simon task between two individuals. To this end, 24 pairs of participants performed a joint shape discrimination task in which each participant had to respond to only one of two possible shapes presented to the right or to the left of fixation. Participants’ responses were assessed in relation to shape and location of the current and previous trials (IOR paradigm). Responses to successive trials were given by the same participant when the shape was repeated and by different participants when the shape changed. Results showed that the repetition of stimulus location determined a large inhibitory effect when the shape was not repeated, and a small facilitatory effect when the shape was repeated. In addition, we found a social Simon effect that was modulated by repeating stimulus location and by the gender of participants’ pairs. In particular, IOR reduced the social Simon effect rather than amplifying it, in contrast to the standard Simon effect