In this case, even when two pieces or objects are identical in shape and size, one looks bigger than the other, which is a result of the misleading perspective cue.

Illusion of Perspective: Another name for this illusion is the Ponzo illusion.

Further, it is caused as a result of our interpretation of angles at the ends of the lines. In this case, both the lines are similar but still, the bottom line is perceived by the person as longer.

Illusion of Length: It is also called as Muller-Lyer Illusion.

It basically depends on how far or near the object is.

Illusion of Size: In this type of illusion, the person has the wrong perception of the size of the object.Conversely, in the case of imagination, the perceived object is a creation of the mind of the person concerned, which is not the case of illusion. One should not confuse between an illusion and dream, and also between illusion and imagination, because in the case of illusion the perceived stimuli are present however in the case of a dream, there is no object present in reality. Further, the misperception of a real external stimulus generally takes place when the basic level of sensory stimulation i.e. So, the misperception arising out of a misinterpretation of the information gathered by the sensory organs is regarded as an illusion. Illusion can also be termed as an error of perception. Therefore, in an illusion, we mistakenly perceive an object for some other object. When a person wrongly perceives one object in a way that is not the same as the actual quality of the object, it is called illusion. Perceiving a snake while there is nothing. No, it is not normal, it represents mental illness. Hallucination is a false sensory perception, which a person experiences without actual external stimulus.Įxperienced by the person concerned only. Illusion is the misperception of an real external stimulus like perceiving the shape, size, color, texture, height, etc.

This post will help you understand the basic difference between illusion and hallucination. However, in illusion, there is some external stimulus that is to be seen or heard, but the impression received by the person concerned is misinterpreted. When there is hallucination, an individual is seen in complete darkness or hears some voices when there is no sound at all.

Size perception definition