Examining the effects of free gaze and dynamic video stimuli on engagement, eye movements, and EEG signal quality in a visual aesthetic rating task
AO_SCPLOWBSTRACTC_SCPLOWFree gaze and moving images are typically avoided in EEG experiments due to the expected generation of artifacts and noise. Yet for a growing number of research questions, loosening these rigorous restrictions would be beneficial. Among these is research on visual aesthetic experiences, which often involve open-ended exploration of highly variable stimuli. Here we systematically compare the effect of conservative vs. more liberal experimental settings on various measures of behavior, brain activity and physiology in an aesthetic rating task. Our primary aim was to assess EEG signal quality. 43 participants either maintained fixation or were allowed to gaze freely, and viewed either static images or dynamic (video) stimuli consisting of dance performances or nature scenes. A passive auditory background task (auditory steady-state response; ASSR) was added as a proxy measure for overall EEG recording quality. We recorded EEG, ECG and eyetracking data, and participants rated their aesthetic preference and state of boredom on each trial. Whereas both behavioral ratings and gaze behavior were affected by task and stimulus manipulations, EEG SNR was barely affected and generally robust across all conditions, despite only minimal preprocessing and no trial rejection. In particular, we show that using video stimuli does not necessarily result in lower EEG quality and can, on the contrary, significantly reduce eye movements while increasing both the participants aesthetic response and general task engagement. We see these as encouraging results indicating that - at least in the lab - more liberal experimental conditions can be adopted without significant loss of signal quality. HighlightsO_LIWe assess trade-offs between EEG quality and behavior for common task constraints C_LIO_LIInvestigated constraints: fixation task vs. free gaze, and video vs. static stimuli C_LIO_LIMeasures: EEG quality, aesthetic preference, task engagement, gaze and heart rate C_LIO_LIVideo stimuli reduce eye movements, increase engagement and do not affect EEG SNR C_LIO_LIFixation task only slightly increases SNR and does not influence ratings C_LI