Is there any difference between the spatial response code elicited by bilateral symmetrical biological and non-biological stimuli?

Abstract: The aim of the present study was to investigate whether the biological relevance of the stimulus could enhance task-irrelevant spatial information delivered by a pair of bilateral stimuli. Participants had to perform a Simon-like task in which they were required to respond to the color of two framed squares (on and off-centered), two framed arrows, or two schematic eyes by pressing one of two keys on the left and on the right of the body midline. Results showed that regardless of stimulus type responses towards the direction indicated by the stimuli (corresponding stimulus-response pairings) were faster than responses against it (non-corresponding stimulus-response pairings). It is argued that the biological relevance of the stimuli does not seem to play a crucial role in the automatic processing of stimulus inherent spatial properties.