1 3 Exp Brain Res DOI 10.1007/s00221-013-3798-4 RESEARCH ARTICLE Dissociating affordance and spatial compatibility effects using a pantomimed reaching action Samuel Couth · Emma Gowen · Ellen Poliakoff Received: 9 September 2013 / Accepted: 27 November 2013 © Springer-Verlag Berlin Heidelberg 2013 later kinematics of the reaching action was influenced by the spatial compatibility of the stimulus alone. Overall, the dissociation of affordance and spatial compatibility effects suggests that these effects are driven by visuomotor prim- ing and the inhibition of the incompatible spatial location, respectively. Keywords Spatial compatibility · Affordance · Kinematics · Visuomotor Introduction As we move through our environment and interact with it, we must recognise the most salient cues in order to effec- tively coordinate our behaviour. One class of cues consists of the intrinsic properties of an object and what they can offer us in terms of action, termed as object affordances (Gibson 1977). For example, a chair affords sitting, whilst a football affords kicking and a mug affords drinking. In support of this, neuroimaging has revealed that observing an affording object can elicit activation within the visuo- motor system, even if there is no intention to interact with the object (Grèzes et al. 2003; Pappas and Mack 2008). Meanwhile, other studies have measured the effect that affordances have on actions, in particular manual reac- tion times (RTs). For example, Tucker and Ellis (1998) employed a task-irrelevant paradigm where participants judged whether an object (e.g. a frying pan) was inverted or upright using a left/right button-press response. The object’s handle could either be oriented in the same direc- tion as the responding hand (compatible) or away from the responding hand (incompatible). Despite the fact that attention was not directed towards the affording features of the objects (handle orientation), RTs were faster in the Abstract Previous research has demonstrated faster reac- tion times in response to appropriately oriented action- inducing stimuli (affordance effect, e.g. Tucker and Ellis in J Exp Psychol Hum Percept Perform 24:830–846, 1998). However, it has been argued that faster responses may be due to a spatial compatibility effect. In the current inves- tigation, we aimed to dissociate the affordance and spatial compatibility effects. Moreover, we explored these effects beyond button-press responses by measuring detailed kin- ematics of the arms and hands during a naturalistic reach response. Participants were presented with images of a door handle (affording) or an abstract (non-affording) stim- ulus and made a pantomimed reach response with either hand depending on a colour change of the stimulus (i.e. Blue = left, Green = right). Stimuli could be aligned as spatially compatible or incompatible with the responding hand. The colour change occurred after a delay of 0, 500 or 1,000 ms. Only spatially compatible affordance stimuli facilitated reach onset compared to other stimuli and com- patibility combinations, replicating previous reaction time studies. Therefore, in the absence of graspable stimuli, spatial compatibility alone was not sufficient to facili- tate reach onset. There was also a larger outwards devia- tion of reach trajectory for spatially incompatible abstract stimuli compared to spatially compatible abstract stimuli, which waned with stimulus onset delay. However, no such affect was observed for the affording stimuli. Accordingly, S. Couth (*) · E. Gowen Faculty of Life Sciences, University of Manchester, Carys Bannister Building, Dover Street, Manchester M13 9PL, UK e-mail: Samuel.couth@manchester.ac.uk E. Poliakoff School of Psychological Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK