Population Screening for Perceptual Phenomena


Research suggests that what constitutes a ‘normal’ perceptual experience can vary widely between people. From time to time, most people experience perceptual phenomena such as static in the visual field, ringing in their ears, or floaters (etc). Sometimes these perceptual phenomena co-occur in interesting ways and can impact other aspects of cognition. This project aims to develop a screening tool for future researchers to use to identify people with certain patterns of perceptual experience. The screening tool will include a questionnaire and a series of visual tasks conducted online. Finally, this project also aims to validate the use of online visual tasks against traditional laboratory-based methods.

Research Questions / Hypotheses

  • Is screening of specific populations using questionnaires and behavioural tasks a reasonable way to identify people with certain perceptual phenomena?
  • What is the prevalence of certain perceptual phenomena among participants in the School of Psychological Sciences' Research Experience Program?
  • How does visual comfort differ between people with certain perceptual phenomena and other participants?
  • Are online tasks a valid proxy for lab-based psychophysical tests?


328 REP students participated in the study this semester. Five participants were excluded because they did not complete the screening questionnaire. We will not be conducting analyses on data from the visual tasks until later this year. At this point, further participants may be excluded if there is not sufficient data on their visual performance to conduct analyses. For example, we are aware of a problem with the server on which we host our visual tasks which has led to a small amount of data loss.


Our study involved a screening questionnaire, investigating whether participants experience certain perceptual phenomena. Participants who experienced certain phenomena of interest also answered questions about how often they experience these phenomena, and whether the phenomena impacted their lives. As well as original questions developed by the researchers, the questionnaire included aspects of the European School for Interdisciplinary Tinnitus Research Screening Questionnaire (ESIT-SQ) and the Tinnitus Handicap Inventory (THI). Regardless of their questionnaire responses, all participants then took part in some visual tasks. The first task involved visual experience matching. Participants were asked to look at a series of images and identify which best matched their own visual experience. For each series of images, a scenario was provided in a question, such as “Which looks most like how you see the blue sky?”. Participants were asked to make their judgments as quickly and accurately as possible. The second task investigated visual comfort using MoirĂ© patterns. Participants were asked to identify which of two MoirĂ© was most comfortable to look at, and to do so as quickly as possible. The final task was a variant on the exogenous Posner cuing paradigm, adapted from the work of Taylor et al. (2018). First, participants saw a fixation cross appear on the screen. Participants were instructed to keep their eyes on the fixation cross. Next, a series of circles appeared around the cross. Then, all but one circle was dimmed, ‘cuing’ the remaining circle and drawing the participant’s attention to that circle. Finally, a Gabor (a striped shape) appeared inside one of the circles. Sometimes, it appeared inside was the ‘cued’ circle and sometimes it did not. Participants were instructed to press the space bar on their computer as soon as they saw the Gabor appear.


Our main analyses will be conducted after the conclusion of semester 2’s REP. Participants from this semester will be invited to take our study again, for us to investigate the test-retest reliability of our screening tool (i.e., whether participants respond the same way after a period of time has passed). Apart from investigating test-retest reliability, we will investigate how many participants experienced any of the perceptual phenomena we are interested in; how many participants experienced several phenomena; and whether there are certain patterns of phenomena which often occur together. For example, is tinnitus commonly experienced alongside any of our visual phenomena? Finally, we will investigate whether people who experience certain perceptual phenomena performed differently on the visual tasks.


The results of this study may help future researchers identify people who experience certain perceptual phenomena of interest. This is important because it will allow researchers to study people who experience these phenomena without having to advertise for participants with specific experiences. The results will be communicated in journal articles, conference presentations, two Honours theses, and a PhD thesis.