What is perception and how does it work?

You reach for a cup, recognise a familiar voice or step around a puddle without stopping to analyse every detail. Each action depends on perception. Information about the surroundings becomes meaningful enough for you to do something with it.

Perception is the process through which we pick up, organise and interpret sensory information. It helps us recognise objects and events, orient ourselves and respond to what is happening. Understanding perception means looking at the relationship between our senses, previous experience and the activities in which we are involved.

Sensation and perception

Sensation concerns the detection of stimulation. Light reaches the eyes, pressure deforms the skin and sound waves reach the ears. Sensory receptors convert aspects of this stimulation into signals that the nervous system can use.

Perception concerns what we make of that information: a face, a rough surface, a voice approaching from behind. These are useful distinctions, although sensory processing and interpretation are closely connected rather than two completely separate stages.

Imagine hearing a short sound outside. You might first be uncertain whether it came from a bicycle bell, a phone or someone striking a glass. Seeing a cyclist gives the sound a context. What you hear becomes part of a more coherent event.

Different forms of perception

Vision provides information about such properties as shape, colour, movement and distance. Hearing helps us locate and distinguish sounds, including speech. Smell and taste contribute to how we experience food and detect aspects of the environment.

The familiar five senses are only a starting point. Proprioception concerns the position and movement of the body, while the vestibular system contributes to balance and orientation. Within bodily sensation, touch, temperature and pain also need to be distinguished. Calling all of this simply touch can hide important differences.

Consider picking up a cup. You see its shape and position, feel pressure against your fingers and sense the position of your hand. If the cup is unexpectedly hot, your response changes. Several sources of information contribute to the same activity.

How the senses work together

In everyday life, information from different senses often concerns the same object or event. We can both see a person speaking and hear their voice. We can inspect a surface with our eyes and explore it with our fingers.

Ernst and Banks (2002) investigated how people combined visual and haptic information when judging height. Participants combined the information in a way that was close to a statistical model giving greater weight to the more reliable cue. The finding concerns a particular experimental task; it does not mean that sensory information is always combined perfectly.

This is one reason perception is relevant to multimodal communication. Several forms of information can contribute to what we understand, and the relationship between them matters.

Attention changes what we notice

A detailed environment can contain much more information than we report noticing. A task directs our attention towards some events and away from others.

Simons and Chabris (1999) demonstrated this in their research on inattentional blindness. People monitoring an activity could miss an unexpected event in the same scene. Detection depended on factors including the demands of the task. The study illustrates a limit of awareness: something may be available to vision without becoming something we consciously notice.

An everyday example is searching a crowded desk for a particular document. You might overlook an object that someone else notices immediately. This example is an illustration, rather than a test of the same experimental effect, but it helps us ask what a person was attending to before assuming that they simply failed to look.

Affordances and the possibilities for action

James J. Gibson introduced affordances as possibilities for action offered by an environment in relation to an animal's capabilities (Gibson, 1979). A surface may afford sitting, a gap may afford passage and an object may afford grasping. The relationship matters: a gap passable for a small child may be too narrow for an adult.

An affordance is not identical to a visual hint about what to do. Norman (1999) distinguished actual possibilities for action from perceived affordances and learned conventions in design. A door may physically allow pulling while its appearance leads someone to push. This distinction helps explain why a usable design must consider both what people can do and how they discover it.

In the cup example, the handle offers a way of grasping it. Whether that action works also depends on the person's hand, the handle's size and the cup's position. Perception is closely connected to the practical question of what can be done here.

Experience and interpretation

Past experience helps us recognise familiar objects and situations. The same sound can be immediately meaningful to someone who works with a particular machine and puzzling to a visitor. The visitor can learn what to listen for.

This does not make perception arbitrary. There is a world that constrains what we can perceive and do. At the same time, familiarity, attention and the available information can differ between people. When two people report different things, a useful first question is what each could see, hear or otherwise detect from their position.

The question becomes especially interesting when the object of perception is another person. The companion article on social perception considers how we move from seeing and hearing someone to forming an impression of them.

Perception in everyday life

Understanding perception can help us design clearer environments, explain an unfamiliar task and examine misunderstandings. Before deciding that a signal was obvious, consider whether it was detectable, whether attention was directed towards it and whether its meaning was familiar.

The next time you reach for a cup, notice how little deliberate effort the action requires. Seeing, feeling and moving come together in an activity that usually seems straightforward. Perception makes that everyday coordination possible.

References

Ernst, M. O., & Banks, M. S. (2002). Humans integrate visual and haptic information in a statistically optimal fashion. Nature, 415, 429–433. https://doi.org/10.1038/415429a

Gibson, J. J. (1979). The ecological approach to visual perception. Houghton Mifflin.

Norman, D. A. (1999). Affordance, conventions, and design. Interactions, 6(3), 38–43. https://doi.org/10.1145/301153.301168

Simons, D. J., & Chabris, C. F. (1999). Gorillas in our midst: Sustained inattentional blindness for dynamic events. Perception, 28(9), 1059–1074. https://doi.org/10.1068/p281059

Adapted from the Swedish article: https://www.vardagspsykologi.com/vad-menas-med-perception

 

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