Our senses are amazing. Seeing, hearing, touching, smelling and tasting: they all work together to form sensations and stand in for each other if needed. When sensations are enhanced by our learnings and experiences we call it perception. Together, sensation and perception make humans truly unique.
Team work makes the sensory dream work
Each of our senses works effectively alone, but the truth is our senses often pair up to make us work more efficiently.
Scientific American notes, “To our brains, ‘taste’ is actually a fusion of a food's taste, smell and touch into a single sensation. This combination of qualities takes place because, during chewing or sipping, all sensory information originates from a common location: whatever it is we're snacking on.”
Another study noted the same is true of seeing and hearing, that how people interpret sounds depends on visual clues. They gave the example of when a car beeps its horn – people respond without alarm if they are in the safety of their own homes but are startled to hear the same horn when crossing a busy street.
Is one sense more important than the other?
It is an age-old debate and one for which there is no definitive answer. What makes a sense more or less valuable? And, are some senses fundamentally more important in making us human?
In the debate many people would normally opt for vision since the brain seems to have a vision focus. The primary brain area for processing visual stimuli, the visual cortex, takes up the largest area of any individual sense. Partly because of this vast processing resource, vision is the most acute sense we have for various kinds of discrimination. There are also several examples of where vision “highjacks” other senses if say there is a conflict. In the famous rubber hand illusion, stroking a realistic dummy hand in front of a person (and hiding their own hand) can make the person feel as if it is their own hand that is being stroked.
However there is research which indicates that the hierarchy of senses actually depends on your culture. Speakers of 20 diverse languages, including three different sign languages, were asked to describe colours, shapes, sounds, textures and smells. If the commonly held hierarchy of the senses were true, participants in the study should have been able to communicate about vision most easily, followed by sounds, the textures, finishing with taste and smell. However while English speakers behaved predictably, describing sights and sounds with ease, speakers of other languages performed much better on the other senses. Speakers of Farsi and Lao could perfectly identify taste, for example, perhaps reflecting the importance of cuisine in their culture. Speakers of Umpila, a traditional hunter gatherer group from Australia, outranked all other cultures in talking about smell.
Our brain allocates priority to things we sense
Do we simply see, hear and smell everything around us without prejudice or is there prioritisation in play here? The fact is, we can “hear” many different sounds at once, but we can only listen to a couple at a time. Our ears automatically pick out noises we’re conditioned to react to, like an ambulance siren or a baby’s cry. It is a similar story with things we look at. When looking at a painting, most people’s eyes are drawn to the same spots. The first things we look for in an image are human faces. So after staring at an artwork for five seconds, you may be able to say how many people are in it and what they look like, but probably unable to list the inanimate object in the scene.
Our senses therefore are constantly detecting but our brain decides which objects, noises and tastes need to come to the forefront.
Do senses replace each other?
Novelty concepts such as dining in the dark which have risen in popularity over the past decade would indicate so. This is where restaurant-goers give up their sense of sight as a way to have a “heightened” mealtime experience.
But the novelty is also supported by research. In behavioural tests, a team from Canada's University of Western Ontario determined that domestic cats born deaf have better peripheral vision and motion-detection abilities than cats born with normal hearing—a finding that parallels visual test results in deaf people. Blind people have a similar experience - since they no longer need to use the relevant part of their brain to process images, more energy and processing power is shifted to the senses of hearing and touch, which will improve their ability to move through the world. For example, blind individuals often use a technique called “clicking”, in which they make small clicking sounds and then interpret the echo they hear to determine the environment around them. This echolocation technique can even allow people to determine specific objects and walk normally without bumping into walls or obstacles. The heightened sense of hearing allows the brain to differentiate the echoes that return after these clicks, a feat that seems impossible to those of us who typically rely on vision.
This is all thanks to our unique plastic brain. When certain pathways are “closed off,” the brain is able to take a detour of sorts. New connections are always forming, old or unused connections weaken over time; thus, the brain is always morphing and responding to the environment and the signals provided to it.
Sensation versus Perception
Sensation and perception are two separate processes that are very closely related. Sensation is input about the physical world obtained by our sensory receptors, and perception is the process by which the brain selects, organizes, and interprets these sensations. In other words, senses are the physiological basis of perception. Perception of the same senses may vary from one person to another because each person’s brain interprets stimuli differently based on that individual’s learning, memory, emotions, and expectations. The philosopher Immanuel Kant put it wisely when he said: “we see things not as they are but as we are“.
The great illustration of the difference between sensation and perception is if someone were to park their car and walks away from it while continuing to look back at it. As they got further and further away from their car, it would appear as if the car is getting smaller and smaller. But in this situation would we really think our car is shrinking? Our senses (vision) tell us that it is, but from past experiences we have learned that objects do not grow or shrink as we walk toward or away from them. Thank you perception!