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7.1: Introduction

Open Neuroscience Initiative · LibreTexts

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    From LibreTexts, under CC BY-NC 4.0, as the source states it; its equations are written in TeX, which the PDF shows typeset. This page at LibreTexts.

    Austin Lim, PhD (DePaul University)

    Editor: Dana Simmons, PhD (University of Chicago)

    Allison Morales, OD (Illinois College of Optometry)

    At over 400 miles of explored passages, the Mammoth Cave system in Kentucky is the longest known cave system on Earth. During the cave tour, the guides momentarily extinguish all the lights. The void that follows is overwhelmingly eerie. Opening and closing your eyes makes no difference. You may have difficulty figuring out which way is up and down, and might even lose your balance when you tilt your head.

    Humans are remarkably dependent on the visual system to gain information about our surroundings. Consider how tentatively you walk from the light switch to your bed right after turning off the lights!

    The visual system is complex and consists of several interacting anatomical structures. Here, we will describe the process of how photons of light from our surroundings become signals that the brain turns into representations of our surroundings.

    Sensation vs. perception

    The following 3 chapters are focused on sensation and perception. By definition, the words “sensation” and “perception” are very similar. However, in psychology and neuroscience, the two have slightly different meanings. Both terms are related to processes of getting information from the environment. “Sensation” is the detection of stimuli, whereas “perception” is the interpretation of those stimuli. The quantity of stimuli that you sense far outnumbers what can realistically be perceived. For example, imagine you are at a loud party, having a conversation with someone. You sense so many things here: all the friends and strangers you see, the smells of sweat or food, and the sounds of music and various voices. But while speaking to your friend, all you perceive is the person in front of you while all the other stuff fades into the background.

    Perception is also shaped by past memories. Consider the following scenario. You are at home, studying by yourself quietly, when you hear footsteps and the jingling of keys. This process is sensation. Based on the fact that you have a roommate, and you know they have a nightly routine of studying late at the library before returning home, you interpret those sounds as your roommate coming home. This process is perception.

    Illustration
    Figure 7.1 Sensation refers to the ability to detect stimuli, while perception is concerned with interpretation of those stimuli.

    This page titled 7.1: Introduction was last modified on Wed, 08 Jul 2026 03:46:43 GMT and is shared under a CC BY-NC 4.0 license and was authored, remixed, and/or curated by Austin Lim via source content that was edited to the style and standards of the LibreTexts platform.