Stairs as multifunctional spaces: Cortical responses to environmental affordances incorporate the intention to act

Abstract

Urban planning and design principles would benefit from enhanced understanding of how public spaces afford engagement. Place affordances refer to the behaviours that the architecture of a place enables the perceiving agent to enact and are incorporated into the early stages of human perceptual processes. However, less is known about how an agent's action intentions are integrated into the perception of affordances. In the present study, we presented participants with images of an architectural structure featuring lateral and central staircases with either high or low steps whilst recording brain activity with electroencephalography (EEG). Participants were primed to consider either reading a book, or meeting friends in the places, and were asked to rate the appropriateness of the places for the given activity and to select the location within the scene where they would conduct that activity. There was also a control condition with no primed activity that involved aesthetic ratings of the same places. Behavioural ratings showed that high steps were preferred for reading compared to low steps whereas step height was not a significant factor for conducting a social activity. Participants preferred the lateral stairs to read on, but shifted to the central stairway when the high steps were central with low steps on the lateral sides. In contrast, participants preferred the central stairway to conduct a social activity in all stair configurations. The EEG data showed no significant differences between the two activity conditions in early perceptual processes. However, pronounced differences in early brain dynamics were observed when participants judged places for activities compared to aesthetics. Specifically, latencies of the visual evoked P1 component were shorter and amplitudes were reduced for the aesthetic ratings, which also yielded larger P2 and P300 amplitudes, signifying modulation of perceptual and attentional processes for the exact same stimuli, by the intention to act. These results demonstrate the importance of human action intentions in the environment when considering place affordances.