The process of organizing and interpreting information, enabling us to recognize meaningful objects and events.

Perception allows us to take the sensory information in and make it into something meaningful. Perceptions can vary from person to person due to the fact that everyone has a different level of intellect, different preconceived ideas and ideologies and most importantly different opinions. A particular thing or situation can be perceived differently depending upon the above mentioned factors.

 People perceive things differently. We choose to select different aspects of a message to focus our attention based on what interests us, what is familiar to us, or what we consider important. Often, our listening skills could use improvement. Listening and thinking are directly related. Person perception is a very subjective process that can be affected by a number of variables. Factors that can influence the impressions you form of other people include the characteristics of the person you are observing, the context of the situation, your own personal traits, and your past experiences.




Perception of depth and distance : In two dimensional surfaces

Depth perception is the ability to perceive the world in three dimensions (3D) and to judge the distance of objects. Your brain achieves it by processing different pictures from each eye and combining them to form a single 3D image.

Depth perception arises from a variety of depth cues. These are typically classified into binocular cues that are based on the receipt of sensory information in three dimensions from both eyes.

Monocular cues that can be represented in just two Dimensions and observed with just one eye.

Some important monocular cues that in judging the distance and depth in two dimensional surfaces are as follows:

Relative Size : The size of retinal images allows us to judge distance based on past and present experiences with similar objects as the object gets away the retinal image becomes smaller and smaller one tends to perceive an object farther away when it appears small and closer when it appears bigger.

Example – The last tree in the lane appears to be smallest and as the distance decreases , the first one which is near to us , we perceive it as the biggest tree.



Overlapping : These cues occur when some portion of the object is covered by another object the overlapped object is considered farther away whereas the object that covers it appears nearer.

Example : Here in this picture we perceive the triangle which is overlapped by the other one , a little far away.



Linear Perspective :  This reflects a phenomenon by which distant objects appear to be closer together than the nearer objects for example parallel lines such as rail tracks appear to converge with increasing distance with a vanishing point at the horizon the mode the lines converge the farther away they appear.

System of creating an illusion of depth on a flat surface. 

In this example they seem to meet at a point as we go further and further. But they are parallel lines.




Aerial Perspective : The air contains microscopic particles of dust and moisture that make distant objects look hazy or blurry this effect is called idiot perspective for example distant mountains appear blue due to the scratch scattering of blue light in the atmosphere whereas the same mountains are perceived to be closer when the atmosphere is clear.


Light and Shade : In the light some parts of the object get highlight some parts become darker highlights and shadow provide us with the information about an object distance .

Relative Height : Larger objects at received as being closer to the viewer and smaller objects as being farther away when we expect two objects to be the same size and they are not the larger of the two will appear closer and the smaller will appear farther away.

Texture Gradient : It represents phenomena by which the visual field having more density of elements is seen farther  away.

As distance increases, a texture gradually becomes denser and less distinct Texture gradient refers to the gradual reduction of detail that occurs in a surface as it recedes into the distance, compared with a surface that is close and perceived in fine detail

Motion Parallel : It is a kinetic monocular cue and hence not considered as a pictorial cue it occurs when objects at different distances move at a different relative speed the object appears to move slowly than the object that is closed the rate of an object movement provides a cue to its distance for example when we travel in a bus closer objects move against the direction of the bus whereas the farther objects move with the direction of the bus.



An illusion is a sensory distortion that can fool a person’s senses. Illusions can involve any of the senses, but visual (optical) illusions are the best understood by science. … Illusions occur when a situation distorts a person’s capacity for depth and motion perception and perceptual constancy.

Some famous illusions are as follows :

Muller Lyer  Illusion :



Here we tend to see 1st line as smallest , middle one as the largest.

But all the lines are of same length , only the arrow changes the perception.


Optical Illusion

Young lady old lady. 

Some perceive this picture as young lady where as in the same picture illusion of an old lady is also there . If you closely notice , the ear of the girl as the eye of the old lady, then you would be able to see the other perspective also.






Zöllner Illusion

The illusion is a classic optical illusion named after its discoverer, German astrophysicist Johann Karl Friedrich Zöllner.

A visual illusion in which parallel lines appear to diverge when one of the lines is intersected by short diagonal lines slanting in one direction, and the other by lines slanting in the other direction. [ Johann Karl Friedrich Zöllner)




Rabbit or Duck ??



Refrences :




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