Body and head tilt reveals multiple frames of reference for spatial attention

Most modern theories of spatial attention suggest that it is based on a maplike representation that prioritizes information in some spatial locations over others. However, movement through space changes the relationship between what is "out there" and a person's viewpoint. Does spatial attention move with the viewer, or does it stay in environmental locations? Several recent psychophysical and neuroscience studies have attempted to address this question by probing attention following saccadic eye movements. The alignment of the head and body to the external environment in these studies, however, makes it impossible to determine whether attention is based on the viewer's location in space or on the external environment. The current study therefore introduces a head and/or body tilt through the vertical plane to dissociate viewer-centered from environment-centered representations. Participants first acquired a long-lasting attentional bias to a region of the search display that was likely to contain a target. They then tilted their head or body, and the location of the spatial bias was evaluated. The results suggest that attention has both a viewer-centered component that rotates with the viewer's head and an environmentcentered component that is tied to environmental locations.