Böckler, A. , Knoblich, G. & Sebanz, N.
Donders Center for Brain, Cognition, and Behaviour, Nijmegen, NL
People take a co-actor’s perspective on a jointly attended scene into account and give up their egocentric view when the other’s spatial perspective is noticeably different. Present experiments investigated whether people’s performance is also affected by a co-actor’s focus of attention - even when spatial perspectives do not differ. Two participants were sitting next to each other while each performed a two-choice Navon task, responding to the identity of letters consisting of similar (congruent) or different (incongruent) smaller letters. Stimuli and responses of the two participants were kept independent. The critical manipulation concerned the focus of attention: participants either attended to the same aspect of the letters (e.g. both to the local aspect/small letters) or they attended to different aspects. Results revealed a significant slow-down of responses when participants focused on different aspects. This slow-down did not depend on participants attending to the same stimulus location, but the effect broke down when the other’s stimuli could not be perceived. An EEG-study revealed effects of the co-actor’s focus of attention on components related to attentional processing. Taken together, this may indicate that the co-actor’s different focus can’t be ignored and induces the need to re-focus on one’s own stimulus aspect.