Non-target flanker effects on movement in a virtual action centred reference frame.

Visual selective attention is thought to underly inhibitory control during pointing movements. Accounts of inhibitory control during pointing movements make differential predictions about movement deviations towards or away from highly salient non-target flankers based on their potential cortical activation and subsequent inhibition: (1) Tipper et al. (Vis Cogn 4:1-38, 1997) "response vector model" predicts movements away from highly salient flankers; (2) Welsh and Elliott's (Q J Exp Psychol 57:1031-1057, 2004a and J Mot Behav 36:200-211, 2004b) "response activation model" predicts movements towards highly salient flankers early in the response, that is resolved by a race for inhibition. To eliminate the confounds of physical properties, such as obstacle avoidance and information cues of non-target objects, pointing was conducted in a virtual environment (graphical user interface). Participants were 14 skilled computer users who moved a computer cursor with a mouse to virtual targets. Analysis revealed non-target flankers significantly interfered with movement consistent with action centred selective attention, and reflecting a proximity-to-hand effect. Spatial analysis revealed evidence of highly salient flankers attracting movement, and less salient flankers repelling movement, supporting Welsh and Elliott's response activation model. These effects were achieved in a virtual 2D environment where interference caused by the physical properties of objects was less cogent.