Apparent motion cues distort object localisation in egocentric space.

The visual localisation of objects in space is thought to rely on retinal information defining the environmental context and non-retinal cues from proprioception and motor commands. Here, the influence of dynamic contextual cues on the perception of egocentric space in a reaching task was investigated. Compared to performances with realistic motion or static cues, target localisation was less accurate when apparent motion was used to provide contextual information about space between the hand and the target. This effect could not be explained by the 'presence' of motion, or a bias in depth perception. Since the distortion was connected with the reaching area it was concluded that cognitive factors can unconsciously influence the perception of egocentric space, in particular distance estimation. We propose a mechanism for this whereby signals from areas MT/MST (middle temporal/medial superior temporal) create a perceptual bias through cortico-cortical connections with posterior parietal cortex.