Observed bodies generate object-based spatial codes

Contemporary studies of spatial and social cognition frequently use human figures as
stimuli. The interpretation of such studies may be complicated by spatial
compatibility effects that emerge when researchers employ spatial responses, and
participants spontaneously code spatial relationships about an observed body. Yet,
the nature of these spatial codes – whether they are location- or object-based, and
coded from the perspective of the observer or the figure – has not been determined.
Here, we investigated this issue by exploring spatial compatibility effects arising for
objects held by a visually presented whole-bodied schematic human figure. In three
experiments, participants responded to the colour of the object held in the figure’s left
or right hand, using left or right key presses. Left-right compatibility effects were
found relative to the participant’s egocentric perspective, rather than the figure’s.
These effects occurred even when the figure was rotated by 90 degrees to the left or to
the right, and the coloured objects were aligned with the participant’s midline. These
findings are consistent with spontaneous spatial coding from the participant’s
perspective and relative to the normal upright orientation of the body. This evidence
for object-based spatial coding implies that the domain general cognitive mechanisms
that result in spatial compatibility effects may contribute to certain spatial
perspective-taking and social cognition phenomena.