By observing things around us, we tend to integrate different parts of visual stimuli and organize them into meaningful ways. In general, we carry out this perceptual elaboration of stimuli completely unconsciously, so it seems to us that we grasp things in this way simply because “they are like that.”
This impression of adherence of the percept to objective reality is normally quite correct, but sometimes perception misleads us as illusory perceptual configurations are created. Sowhat are perceptual illusions? In this Psychology-Online article we are going to see its causes, the different types and some examples.
What are perceptual illusions?
Perceptual illusions represent, unlike perceptual constancy, an inaccurate perception of real objects. Illusion is, therefore, a perceptual alteration by which perception that does not conform to the characteristics of the stimulus causes a discrepancy between the physical world and the perceived world.
It should be said that perceptual illusions They are not only optical illusions, since the latter is based on the introduction of visual tricks that work with human perception; while perceptual illusions are rather a cognitive phenomenon that has as its protagonist the brain processing of sensory information.
Causes of perceptual illusions
The phenomena of perceptual illusions are unequivocal examples of a general truth: perception is organized and cannot be considered simply “given” by the impression of external events. In this way, perceptual illusions are produced by a series of influences:
- Biological influences: our nature of attention is selective and we also see images as perceptual sets (we fill in the spaces of the image to complete it).
- Psychological influences: Perceptual illusions are a product of the emotional context and the schemes learned throughout our lives.
- Sociocultural influences: are those that integrate cultural assumptions and expectations, as well as the effects of the physical context.
Types of perceptual illusions and examples
To better understand what perceptual illusions are, it will help you read the following examples on the subject:
1. Ponzo Illusion
Depth perception It can be altered by drawing two divergent straight lines on the sheet. If equal elements are added to the drawing, but appropriately distanced, the objects that are at the convergence of the lines appear further away and therefore higher than those that are where the lines diverge more.
2. The illusion ofe Kanizsa
Three colored discs placed on the same plane and from which a small portion has been cut out give the illusion that a white triangle is also drawn on the sheet. There is actually no triangle, as is the case when rearranging floppy disks: our mind completes the picture with just the details.
3. The Necker cube
What is the front face of the cube? And the back part? The brain cannot decide why has no reference points to determine which part of the cube is closer and which is farther away.
4. Illusions related to color
In Rubin’s cup Both the object (the cup) and two human profiles can be distinguished depending on whether more attention is paid to the white of the cup or the black of the background.
Another deception in color perception is that which occurs when a homogeneous strip of color is superimposed on a blurred background: the end of the strip that is in the darkest part of the background will appear lighter and vice versa.
5. The impossible figures
There are objects that can only live on paper, but they are totally unrealizable. An example is the endless staircase, in which you can go down or up to infinity because the first and last steps coincide. Endless stairs and other impossible objects are also frequently found in many works made by Maurits Cornelis Escher.
6. Ambiguous images
Young or old? In “My Wife and My Mother-in-Law”, a caricature made by the English artist WE Hill in 1915, you can see both a young woman filmed in three quarters and the profile of a pensive old woman.
Differences between perceptual illusions and hallucinations
Perceptual illusions and hallucinations are phenomena in which an erroneous perception is made. However, unlike the perceptual illusion, which misinterprets a truly existing stimulus, hallucination encounters an external stimulus that does not exist absolutely.
Some examples of hallucinations are: when a person hears a voice without there being a sound or, on the other hand, sees a person and object where there is really nothing or no one. Click on our title if you want to know more about this topic.
Examples of perceptual illusions
Other examples of perceptual illusions that commonly occur are:
The illusion of the moon
The moon appears smaller when it is at its zenith than when it is at the horizon. The explanation of this phenomenon is that The magnitude of an object is determined by comparing it with the environment.
In this way, when we see the moon on the horizon we compare it with elements of the landscape while when it is at the zenith there are no reference points and for this reason it appears smaller to us.
The contrast between black and white
Another situation of perceptual illusion can be easily verified by looking at certain floors with black and white marbles that represent a series of cubes seen of disequilibrium. At times it seems to us that the white faces are “closer” to us, as if they stood out like an extended peak.
However, if we continue to observe, at some point the arrangement is reversed: the white parts move away from us as if they were cavities and the dark parts appear to stand out.
If you liked this article about perceptual illusions, we recommend you read our article, which talks about erroneous interpretations about reality, which prevent us from experiencing the situations that occur to us objectively.
This article is merely informative, at Psychology-Online we do not have the power to make a diagnosis or recommend a treatment. We invite you to go to a psychologist to treat your particular case.
If you want to read more articles similar to Perceptual illusions: what they are, causes, types and exampleswe recommend that you enter our category.
Bibliography
- Burla, F., Capozzi, S., Lozupone, E. (2007). Elements of psychology, pedagogy, sociology for the health profession. Milan: Franco Angeli.
- Canestrari, R., Godino, A. (2002). Introduction to general psychology. Milan: Mondadori.