Both Chapter 5 of Psychology 2e and the associated video cover the difference between sensation and perception and the inner biological workings of human senses. They describe the biological functioning of vision, from the light passing through the cornea, pupil, and the lens and reaching photoreceptor cells – cones and rods. However, neither source provides much detail on the human field of vision, apart from briefly mentioning peripheral vision once. It is particularly notable because, as Strasburger (2020) points out, misconceptions regarding the human field of vision and especially peripheral vision have become prominent enough to find their way into textbooks. This paper will attempt to establish whether the erroneous idea of human peripheral vision extending to 90° at most on the temporal side is actually present in students.
The concept chosen from Chapter 5 and associated materials for further inquiry is peripheral vision. Such an inquiry is all the more necessary because Spielman et al. (2022) only refer to peripheral vision once in the entire chapter when noting that rods are responsible for it. Similarly, the video on sensation and perception also refers to the rods enabling peripheral vision but does not elaborate further (CrashCourse, 2014). The probable motivation behind this approach is that peripheral vision seems like an intuitively understandable concept that does not require a detailed explanation. However, Strasburger (2020) notes that this approach may result in students internalizing erroneous assumptions about vision. In his article, he analyzes some of the most common misconceptions about the human vision that have long been debunked scientifically yet still persist in the popular imagination and even textbooks. Among other things, Strasburger (2020) points out the false assumption that human peripheral vision on the temporal side does not extend further than 90° when it is actually closer to 110°. The author’s concern with the spread of this misconception among students calls for an empirical investigation.
For the purpose of this investigation, a survey containing six questions has been designed to test the students’ understanding of human peripheral vision based on their educational materials and personal experience. The questions were as follows:
- Do you remember the textbook and associated materials covering peripheral vision?
- (only if answered “yes” in the previous question) What did the textbook and other associated materials state about human peripheral vision?
- WITHOUT TESTING IT YOURSELF, estimate the extent of the human field of vision on the nasal side.
- WITHOUT TESTING IT YOURSELF, estimate the extent of the human field of vision on the temporal side.
- Estimate the extent of the human field of vision on the nasal side after having tested it yourself.
- Estimate the extent of the human field of vision on the temporal side after having tested it yourself.
This questionnaire aimed first to establish the students’ theoretical understanding of the human field of vision and then contrast it with the students’ own experience as they tested it themselves. To test their field of vision, the students were advised to move a hand, a pencil, or another stimulus before one opened the eye while looking straight ahead and estimate the extent of their peripheral vision. Questions about the field of vision on the nasal side serve as a reference point to establish the overall accuracy of the respondents’ estimations.
A total of 23 fellow students have been presented with this questionnaire. In the initial sample of 20, 3 students began to test their field of vision when answering questions 3 and 4 themselves despite the requirement not to do so, which is why their answers became inadmissible, and 3 more participants were enrolled for the required minimum of 20. Overall, 13 participants (65%) did not remember specific references to peripheral vision in educational materials. Among the 7 who stated to remember it, 1 failed to provide specifics, and 6 have stated that peripheral vision relies on rods, which is mentioned in educational materials (Spielman et al., 2022; CrashCourse, 2014).
As one can see, the survey provides moderate support for the prevalence of the notion that human peripheral vision on the temporal side is limited to 90°. More than half of the students originally maintained that it was 90° or less, but this proportion was reduced to a mere quarter after the students tested it themselves. The estimations of the field of vision on the nasal side, which is actually about 60°, demonstrate that the respondents judged the angles reasonably well, although they tended to err on the larger side (Strasburger, 2020). Thus, a considerable proportion of students hold a belief about the limits of their peripheral vision on the temporal side, even though it is easy to debunk through their everyday experience.
To summarize, the survey offers some support to the idea that human peripheral vision on the temporal side does not extend further than 90°. However, only 35% of respondents remember peripheral vision mentioned in study materials, and neither Spielman et al. (2022) nor CrashCourse (2014) mention angles. Hence, the causal link between textbooks and this belief, which is postulated by Strasburger (2020), is still questionable. An alternative explanation is that people estimate it to be 90° because it is a neat ‘round’ number, and a better questionnaire would be designed in a way that should somehow account for this possibility.
References
CrashCourse. (2014). Sensation and perception – CrashCourse psychology #5 [Video]. YouTube. Web.
Spielman, R. M., Jenkins, W. J., & Lovett, M. D. (2022). Psychology 2e. Openstax. Web.
Strasburger, H. (2020). Seven myths on crowding and peripheral vision, i-Perception, 11(3), 1–46. Web.