Sensation and Perception
The content in this chapter should be relevant to about 6% of all questions about the behavioral sciences on the MCAT.
This chapter covers material from the following AAMC content category:
6A: Sensing the environment
It’s your first time visiting a country in Europe. You can’t wait to see the glorious, ornate architecture, sample the local cuisine, and listen to the traditional music. You want to take in the sights and sounds of this culture—you want to have a sensory experience. To truly experience any location, your sensory receptors—for vision, hearing, taste, smell, and somatosensation—gather all of the information from the world around you, and your brain filters and processes that information to focus on the most salient details. This activity involves a complex interplay between sensory processes, neural tracts, and the brain itself.
You finally land in your European destination and begin to explore. You turn the corner on one street and are suddenly overwhelmed with an odd feeling of familiarity. But . . . I’ve never been here before! you think as the strange sensation of déjà vu sets in. Everything just seems “right”: the signs are in the proper place, the cars look familiar, and everything is bizarrely where you expect it to be. Déjà vu (French for “already seen”) comes from many sources, including processing information faster than expected. When you process an image (or other sensory input) for the first time, it actually takes longer than the next time you are exposed to that same stimulus. Thus, an exposure to the same scenery at an earlier time through a movie or television show may have primed you for déjà vu.
But we don’t feel déjà vu every time we see an image again; that’s where memory comes in—a topic we’ll discuss in Chapter 3 of MCAT Behavioral Sciences Review. Indeed, this phenomenon of déjà vu comes from the brain’s sensory receptors saying, Yes, you have seen this before! in tandem with the memory system saying, But I don’t know when or where!
In this chapter, we will focus on the concept of sensation and its associated receptors, including the eyes and hair cells in the ear, as well as perception and the complex brain functions associated with processing sensory information. We’ll briefly touch on the other sensory modalities, including vestibular sense, taste, smell, somatosensation, and kinesthetic sense, and consider the roles these senses play in helping us interact with the world.