On the relationship between affordance and Simon effects: Are the effects really independent?

Abstract

The aim of the present study was to investigate the relationship between the affordance effect (i.e., the advantage for responses corresponding spatially with the location of an object's graspable part) and the Simon effect (i.e., the advantage for responses corresponding spatially with stimulus location) and to assess whether they both occur at the response selection stage. In two experiments participants were required to respond according to the vertical orientation (upward or inverted) of photographs of graspable objects, located to the left or right of fixation, with their handles oriented to the right or left. In Experiment 1 the response was a buttonpress; in Experiment 2 was a reaching movement. Our results showed that both Simon and affordance effects emerged in response times but not in movement times. In Experiment 1, the two effects did not interact, whereas a clear interaction emerged in Experiment 2. These results seem to suggest that the interaction between Simon and affordance effects may depend on the type of required action.

Keywords:

• Affordance effect
• Motor control
• Response selection
• Simon effect

Acknowledgements

This work was supported by the EU FP7 project ROSSI, Emergence of communication in RObots through Sensorimotor and Social Interaction, Grant No. 216125. We thank Roberto Bolzani for statistical assistance, Peter Wühr, Claire Michaels, and an anonymous reviewer for helpful comments on an earlier version of the manuscript.

Notes

¹To note, our use of the term “affordance” slightly departs from Gibson's use (1979). Indeed, according to Gibson, affordances are properties of the environment taken with reference to the behaving animal. As such, affordances are not ascribed to objects on the basis of perception or by virtue of representation; they are simply perceived. Differently, in line with the concept of microaffordances introduced by Ellis and Tucker (2000), we refer to those object properties whose representation affords a specific action.

²An analysis of variance with responding hand and handle position as within-subject factors, and condition as between-subjects factor showed only a significant Responding hand×Handle position interaction, F(1, 30) = 10.87, p<.01. Right responses were faster when the handle was on the right (532 ms) than when it was on the left (540 ms). Similarly, left responses were faster when the handle was on the left (530 ms) than when it was on the right (541 ms).

³The analysis of variance with responding hand and handle position as within-subject factors showed that the interaction between responding hand and handle position did not reach statistical significance, F(1, 11) = 2.73, p=.13, meaning that the affordance effect was nonsignificant irrespective of responding hand.

⁴We thank Peter Wühr for suggesting this possibility.