Do we see only what we want? We all have heard of little grooming tips that help us delude the viewer to their advantage. Illusions assist in flattening unwanted curves, curving unwanted flatness, elongating unwanted shortness, shortening unwanted longness and so the list goes. How about a little example for those that think this is all nonsense? “The square on the left is identical to the one on the right, though it appears to be bent at the four corners.” This is one good example, among many, that shows how what we see opposes what we know, almost making what we know irrelevant. I believe there is also a different kind of relationship where what we know influences what we see and that is where things start to get interesting.

Unconsciously, I often find myself engaged in what some might call useless exercises that try to change what I see by changing what I think I see. For instance, I will look at a shadow cast on a table and try to convince myself it is just a darker shade of the table. Sometimes it works and sometimes it doesn’t, which is probably a part of the reason why there are opposing schools of thought on the subject of knowledge and perception. The main difference is between those that argue for top-down processing (meaning brain to eye) where knowledge can influence vision and those that argue for bottom-up processing (eye to brain) where the brain is just a “passive” receiver.

I belong to the camp that thinks bottom-up and top-down do not have to be mutually exclusive, especially since I have experienced both at one point or another. I would divide the type of influence knowledge has on perception into two. One is where the lack/presence of knowledge prevents us from seeing what is in our view and the other is where the lack/presence of knowledge makes us see in addition to what is in our view.

I recently read about a common finding among anthropologists that when they present photographs to members of cultural groups that have no knowledge of photography, the person looking at the photograph does not realize that he/she is seeing a close family member (for instance, a mother did not know what she was looking at when she was handed a picture of her son).¹ This can be an example of a case where the lack of knowledge is preventing perception. They have no prior knowledge about the workings of photography and may not even believe such a thing is possible. Therefore, they would most likely be unaware of what they are seeing.

If we look at the history of western art, we see how it was transformed by the knowledge of perspective. For instance, before this discovery, the accepted knowledge was that a man is bigger than an apple and so this proportion would be maintained in all depictions involving the two. However, once this was replaced by the knowledge of perspective then the proportion depended on how far away the apple and the man were from the viewer. In other words even though nothing about the way we see changed, until the knowledge of perspective was introduced, we could not really see the vanishing point. I wander if here we can also add as an example, the times we search everywhere for our cell phone while it is sitting in the most visible place and yet we fail to see it because we are sure it is intentionally hiding from us.

An emerging area of interest among researchers is whether or not the brain plays a part in creating what we see. Is it the case that we see what we expect to see? One amusing study was conducted by tracking the neural activity of a sleeping cat.² They observed that the types of neural activities evoked by a mental image were similar to those activities evoked by a real-life image. In other words these activities were not expected to take place with the eyes closed and during an absence of a real image. Without getting down to the workings of our visual mechanism, we may be able to identify experiences where we saw something when it was not really there. For instance, up until recently, I could have sworn Da Vinci’s Mona Lisa had eyebrows. Could it be that my introduction to her, as one of the most beautiful women ever painted in our history, assisted in filling in the missing eyebrows? (Allow me to digress here but is it not true that we often say we found someone to be beautiful once we got to know him/her, while nothing about the way they actually look changed? Could it be that what we know about them made us see something different?)

While reading up on the subject of knowledge and perception, I stumbled upon a surprising growing trend of collaboration efforts between scientists and artists. I found this interesting because I would naturally pair knowledge with the sciences and perception with the arts. One of the driving motivations for involving artists in scientific endeavors is to gain a fresh perspective or a new approach. Scientists are also finding that certain visual representations of existing concepts are limiting and therefore need artists to step in with some creativity. Whether or not these efforts prove successful, I believe art is a great tool for expanding knowledge and giving new insights. Art is intelligent enough to undertake the task of understanding human perception and then to use or in some cases to exploit it. Art can surprise by revealing the unexpected, enlighten by displaying the beauty of what was taken for granted and challenge by providing an alternative perspective.