Limitations of parafoveal processing in peripheral vision

¶ … Visual Consciousness

Visual Perception

In conducting this study, the first step I took was to procure a book with a cover on it that I would attempt to read. I have read most of my books, but am unfamiliar with the text on the front of them. I actually selected one of my larger books (it is a coffee table book) in order to maximize my chances of reading. Next, I sat in a comfortable spot and entirely covered my left eye with my left hand. Once I was sure I could not see out of it, I fixated my right eye on a tiny crack in the wall. After doing so, I extended the book in my right hand as far to the right as I could, so that I could not even see it at first. Then, while maintaining my eye on the same crack, I slowly moved the book closer and closer to the point on the wall at which my eye was fixated. Eventually, I moved the book close enough to the spot my eye was fixated upon, at which point I was able to read the text on the front.

Relationship of Findings to the Readings

My research indicates that not only are there severe limitations to parafoveal processing, but also that assuming that parafoveal processing is reliable is an illusion. In this respect, the front end mental processes are circumscribed, which affects the more central ones related to decision making based on that information (Pashler and Johnson, no date). This concept is directly related to the readings regarding blindsight perception. Blindsight is "a kind of residual vision found in individuals who have suffered damage to striate cortex" (Brogaard, 2012, p. 595). There are congruencies between the restricted vision of blindsight patients and that involving parafoveal processing. My research indicates that anyone who claims to be able to use peripheral vision as proficiently as vision involving one's foveal is instead relying on "cognitive phenomenology but not…visual phenomenology" (Overgaard and Grunbaum, 2011, p. 1856). In both cases (those with blindsight and those with parafoveal-based sight) there is strong evidence that suggests that individuals claiming to perceive stimuli are merely guessing.

Additionally, it is notable that there are similarities in the limitations of peripheral vision and that of blindsight. Many of the properties regarding the book that I was able to discern prior to reading it are discussed within the readings. For instance, prior to being able to read the words on the book, I was able to distinguish some of its characteristics pertaining to its movement, shapes, and color, all facets that are discernible with blindsight (Overgaard and Grunbaum, 2011, p. 1855). The more important between the readings and my research, however, is that "an experience that represents a visually processed stimuli need not itself be visual" (Brogaard, 2012, p. 596).

Implications for Understanding Human Experience and Professional Practice

The implications of my research and the reading relate to the fact that there are many cognitive processes involved with stimuli, processing, and representations other than those involving the physical senses. These processes help to account for stimuli requiring selective attention, which in turn makes individuals conscious of things (Baars, 1997, p. 99). However, in some cases processing is related to more than one physical sense, such as what frequently occurs when individuals have visual impairment conditions such as prosopagnosia or achromatopsia, in which restricted vision is augmented by a host of other senses to help people identify characteristics and properties of objects (Celestia, 2010, p. 62). Therefore, it is apparent that perception of objects, particularly that involving sight, pertains to both sensory and extrasensory factors. Some of the more salient of the latter include experience, which is preserved within the mind in the form of memory.

Therefore, it is critical to acknowledge the role that memory and "working memory" (Overgaard and Grunbaum, 2011, p. 1855) play in the process of perception. The ramifications of doing so allude to the fact that not all perceptions are explicitly based on reality and the external stimuli that is a part of it. Some perceptions can be based on previous stimuli and working memory, and are recalled to aid individuals in perceiving present stimuli. This alludes to the fact that there may actually be inaccuracies present with sensory perception, for the simple fact that other aspects of cognition can frequently augment or "modulate" (Railo et al., 2011, p. 972) perceptions so that they are not directly related to the external stimuli of the moment.

Concluding Remarks

The relationship between the cognitive aspect of sensory information and other cerebral processes is profound. Moreover, it appears as though the latter can greatly inform the former. Railo et al. (2011) state that various cognitive outputs can alter and modify perceptions (p. 974) -- which should be taken into account whenever perceptions are used in accordance with important decisions, such as those related to the law.