Abstract

Visual discomfort is the adverse effects of viewing certain stimuli, for example striped patterns and op-art stimuli. This could be due to eye-movements (Zanker, Hermens and Walker, 2010), alternatively discomfort could arise from excessive neural responses (Juricevic, Land, Wilkins and Webster, 2010).

If excessive neural responses are responsible for discomfort, this judgements should relate to the magnitude of the EEG response. Spatial frequency content affects the level of discomfort (Wilkins et al, 1984; Fernandez and Wilkins, 2008). As the visual system is differentially sensitive to spatial frequency (Campbell and Robson, 1968), particularly those judged most uncomfortable (Wilkins et al, 1984), stimuli were matched for perceived contrast.

Two measures of EEG amplitude were taken, transient responses from pattern reversal at 1Hz, and steady-state responses, from 5 and 10Hz. Results show that the transient response amplitude follows the same pattern as discomfort judgements, in accordance with the predictions of hyperexcitation. However, the steady state stimuli show a different pattern of results for the discomfort judgements, possibly due to perceptual phenomena such as frequency doubling.