Sensory Perceptions

Sensation and Perception The issue of being able to trust one's senses has been the topic of many philosophical debates and whole books have been written on this debate. There are convincing arguments made for both sides of the issue. Nonetheless, anyone who ambulates, operates a motor vehicle, eats, interacts with others, etc. trusts the information that their senses give them (Christian, 2011).

Sensory information is the result of physical stimuli collected by sense organs and transferred and processed in the brain, whereas perception is the interpretation of these stimuli that occurs at the higher levels of the brain (Hatfield, 2013). Sensory information in the absence of frank brain damage is an actual reflection of the physical stimulation that is delivered to the various processing areas of the brain (Hatfield, 2013). One's perception of the world is open to subjective interpretation (Hatfield, 2013).

The big question regarding whether one can trust their senses should not be a yes or no question nor should it be an absolute question. So, if the question is "Should you always trust your senses (perceptions)?" The answer is no; however, if the question is "Should you generally trust your senses (perceptions)?" The answer is yes. The dilemma occurs when deciding when to put faith in one's senses/perceptions and when to question and rationally inspect them. For instance, let's suppose you are driving down the freeway.

Should you trust your sensory information? Well, any person that is going to get in a car and drive must certainly have pretty good faith in their senses because driving relies on a combination of sensory feedback, automatic brain processes, controlled brain processes, and the integration of these with motor behaviors.

If you see a car stopped in front of your vehicle you will trust this sensory registration (or perception) and stop your car in order to avoid a collision (otherwise if you decide not to trust them and decide that there is really no car stopped in the road you will be in trouble). However, when looking to change lanes while driving there is good reason not to always trust your perceptions.

As it turns out the brain automatically reconstructs the sensory stimulation in order to form a perception and with regards to visual information there is a blind spot in the visual field where the optic nerve is located in the retina (Snowden, Snowden, Thompson, & Troscianko, 2012). If we were to actually perceive the world as our senses reproduce it there would be a blind spot in our visual world; however, the brain fills in the blind spot based on the visual information around that particular area (Hatfield, 2013).

So we perceive the world visually without a blind spot. If one changes lanes without looking over one's shoulder one may actually run into a car that was perceived as not being there. Moreover our perceptions of the world can be influenced by certain cognitive biases. Our general knowledge of the world is certainly very much dependent on sensory information (Christian, 2011). However, we are also biased to perceive certain relationships or certain things.

For instance, Heider and Simmel (1944) performed a classic study where a circle, a small triangle, and a large triangle moved about and then one of them went inside of a large rectangle. Participants interpreted the scenario as two males (triangles) fighting over a female (circle). Certainly one could trust one's sensory information regarding what was seen but the perceptions based on the sensory information were a little exaggerated. There is a tendency for people to search for cause and effect explanations.

Thus, one's expectations and memory of past events can significantly affect one's perceptions; however, memory may bias perceptions. First, memory is not infallible and one's recall of events can easily be influenced by the conditions under which one recalls them (e.g., Loftus, 1982). Secondly, the process of recollecting an event or situation involves an actual re-creation of that memory in the brain thus making memories susceptible to environmental conditions and previous memories that can interfere with and change the accuracy of the recollection (Hatfield, 2013).

Finally, other perceptions, schemas, his beliefs, etc. interfere with how we perceive events and how we remember things such as how we are fooled by certain visual illusions, form prejudices, etc. (Hatfield, 2013; Snowden et al., 2012). Thus, memory interferes with perceptions/senses at multiple levels. While the undamaged or normally developed brain receives sensory information accurately, perception can also be drastically affected by how people direct their attention.

For example, very famous study by Simons and Chabris (1999) had participants watch a video of a part of a basketball game and instructed them to count the number of times the players passed the ball. In the middle of the video a lady dressed in a gorilla suit walked across the scene, stopped in the middle of the scene, beat her chest, and then walked off camera.

While 100% of the participants reported the correct number of passes nearly 60% of the participants reported never seeing anything other than the players passing the ball. When viewing the video again and told not to count passes but to just watch the video they were surprised to see the gorilla enter the scene. Selective attention has a survival value, but it also can result in perceptions being faulty and inaccurately representing reality. Thus the real question.