Perception

Perception is the organization, identification, and interpretation of sensory information, or information that is gathered through the senses, such as hearing, vision, taste, smell, and touch. Perception allows people to create meaning out of what they see, feel, hear, touch, and experience in the world.

Perception is closely related to sensation, or the detection of environmental stimuli. Sensation is the first step in the perceptive process and is referred to as bottom-up processing. It begins when the body’s sensory receptors in the nervous system receive information from stimuli. This information travels from the nervous system to the brain. Because perception involves the interpretation of sensory information, it is often called top-down processing. In other words, higher-level mental processing is used to interpret the received stimuli and make sense of it.

Perceptions are human constructs; they are ideas created in the mind based not only on environmental stimuli but also on context, personal experience, and expectations. Perception imposes meaning that does not exist in the physical stimuli alone. For example, a loud boom heard outdoors reaches the brain via the sense of hearing. However, it is higher-order processing within the brain that helps the person hearing the noise to perceive that it is thunder (or fireworks, or a car backfiring, etc.). Similarly, if a person reaches into the murky waters of a lake and feels rough scales brush by his or her fingertips, it is the person’s higher-order processing that helps the person perceive that he or she has touched a fish rather than a rock, a weed, or an eel.

The goal of perception is to take in information about the world through the senses and make sense of it.

Gestalt Principles

Gestalt is a term that roughly translates to "unified whole." Gestalt principles of perception were developed by German psychologists in the early twentieth century to explain the observation that humans often experience things that are not a part of simple sensations. For example, when viewing a sequence of rapidly flashing lights, humans generally see motion rather than individual lights being turned on and off quickly.

Gestalt principles, which are sometimes referred to as Gestalt laws, predict the different ways humans will organize visual elements into groups in order to make sense of them. Although many Gestalt principles have been identified, the following are commonly cited:

Figure/ground is one of the defining principles of Gestalt psychology. It refers to the fundamental way that humans organize what they see, by being able to distinguish elements from the framework, or background. For example, when viewing a posed studio photograph, individuals can distinguish the human face (the figure) from the photo backdrop (the ground). Similarly, when admiring new furniture in a living room, people can distinguish the individual elements (couches, chairs, tables) from the background (the surrounding walls).

Similarity refers to objects with similar visual properties. For example, when viewing objects with a similar shape, size, color, orientation, texture, etc., it is easy to group these objects together visually.

Closure refers to the tendency to add the missing parts to an object, or "close" it. For example, if a square drawn on a piece of paper is missing one of its sides, the mind will "see" the missing side in order to complete the object and perceive it as a square.

Proximity refers to objects that are physically close to each other. The mind tends to view these as a single object rather than separate objects. For example, a particular painting technique is known as pointillism. Images created using pointillism consist of thousands of tiny dots placed close to each other. Viewers of such images see the dots together to form shapes rather than as individual objects.

Common fate refers to objects or elements that move together. The human mind groups these objects together because they share a common fate. For example, a flock of birds moving from one place to another is often perceived as a single element. Likewise, fireworks are made up of individual elements of light but are experienced by the audience as a single shape, such as a star or circle.

Gestalt psychology has developed over time to include more than just the relationship between what people see and what they perceive. Gestalt psychology has developed into the theoretical belief that all systems consist of interacting parts that can be isolated, analyzed, and reassembled as a whole. Many modern human endeavors have a Gestalt viewpoint. For example, systems theories consider both the parts (for example, the computer coding) and the whole (a computer system); family systems therapists work with individuals (parts) as part of and yet separate from the family (the whole).

Perceptual Models

Various models have been developed to describe the elements of the perceptual process more fully. For example, the template-matching model describes perception through the recognition of templates, or patterns. When reading text, viewers perceive individual letters and their meaning by identifying in the known templates of letters in the alphabet. They would recognize and differentiate, for example, an "A" from a "D" by considering the different templates of letters that make up the alphabet.

Feature-matching models, on the other hand, theorize that recognition occurs through the identification of specific features, or attributes, of objects. For example, recognizing the letter "A" would involve differentiating its straight-line features from letters such as "C" that have a rounded shape.

Bibliography

Bernstein, Douglas A. "Sensation and Perception." Essentials of Psychology. 7th ed. Cengage Learning, 2017.

Bruce, Vicki, Mark A. Georgeson, and Patrick R. Green. "Perceptual Organisation." Visual Perception: Physiology, Psychology and Ecology. 4th ed. Psychology Press, 2003.

Epstein, William, and William N. Dember. "Perception." Encyclopedia Britannica, 4 July 2024, www.britannica.com/topic/perception. Accessed 5 August 2024.

Kosslyn, Stephen M., and Robin S. Rosenberg. "Sensation and Perception: How the World Enters the Mind." Introducing Psychology: Brain, Person, Group. Version 5.1. FlatWorld, 2020.

Smith, Edward E., and Stephen M. Kosslyn. "Perception." Cognitive Psychology: Mind and Brain. Pearson. 2006.