Live social influences on human spatial attention and action

One of the major goals of behavioural research is to understand how people attend to and interact with objects. In this thesis, I was interested in placing these interactions in an embedded, interactionist framework. That is, I aimed to study them as they often occur in the real world – as part of naturalistic real-time social encounters. The focus of this thesis was on triadic social interactions involving two individuals (an actor and an observer) and one acted-on object. Within this system, I evaluated attention, spatial coding, gaze, and action towards objects that are located in the near space of an observer. I asked: how do social effects across these behaviours relate to one another? Can a guiding principle be identified that predicts when a behaviour should be socially modified? Across several studies, I find that willingness to look at meaningless content and willingness to reach for real objects are both reduced in the space near real others. But, covert attention, spatial coding of objects, and willingness to look at meaningful content did not change. To reconcile the potential conflict between these findings, I made a novel prediction: that willingness to attend and willingness to signal that one is attending can be and are dissociated in naturalistic social situations. This was directly tested using a task where the to-be-attended target is a person who can or cannot see the subjects’ gaze. The prediction was supported; participants selectively modify their visible gaze but not their concealed attentional state when their eyes can be seen. This thesis argues that when objects are located near live others, behaviour is modified to the extent that it has the potential to communicate. So, reaching and looking are modified in the near space of others not as a result of internal shifts in attention but as a process that regulates the social signals that we are willing to send to others.Medicine, Faculty ofGraduat