Perception

What is perception?

Perception (from the Latin perceptio, percipio) is the organization, identification, and interpretation of sensory information in order to represent and understand the environment. All perception involves signals in the nervous system, which in turn result from physical or chemical stimulation of the sense organs. For example, vision involves light striking the retina of the eye, smell is mediated by odor molecules, and hearing involves pressure waves. Perception is not the passive receipt of these signals, but is shaped by learning, memory, expectation, and attention. Perception involves these "top-down" effects as well as the "bottom-up" process of processing sensory input. The "bottom-up" processing transforms low-level information to higher-level information (e.g., extracts shapes for object recognition). The "top-down" processing refers to a person's concept and expectations (knowledge), and selective mechanisms (attention) that influence perception. Perception depends on complex functions of the nervous system, but subjectively seems mostly effortless because this processing happens outside conscious awareness.

Since the rise of experimental psychology in the 19th Century, psychology's understanding of perception has progressed by combining a variety of techniques. Psychophysics quantitatively describes the relationships between the physical qualities of the sensory input and perception. Sensory neuroscience studies the brain mechanisms underlying perception. Perceptual systems can also be studied computationally, in terms of the information they process. Perceptual issues in philosophy include the extent to which sensory qualities such as sound, smell or color exist in objective reality rather than in the mind of the perceiver.

Although the senses were traditionally viewed as passive receptors, the study of illusions and ambiguous images has demonstrated that the brain's perceptual systems actively and pre-consciously attempt to make sense of their input. There is still active debate about the extent to which perception is an active process of hypothesis testing, analogous to science, or whether realistic sensory information is rich enough to make this process unnecessary.

The perceptual systems of the brain enable individuals to see the world around them as stable, even though the sensory information is typically incomplete and rapidly varying. Human and animal brains are structured in a modular way, with different areas processing different kinds of sensory information. Some of these modules take the form of sensory maps, mapping some aspect of the world across part of the brain's surface. These different modules are interconnected and influence each other. For instance, the taste is strongly influenced by its odor.

Why does perception vary from person to person?

Based on personal experiences and beliefs we create our perceptions on particular things, that is why they are differed. in essence your perception becomes your reality.

Belief  - 'mental acceptance of a proposition, statement, or fact, as true, on the ground of apparent authority, which does not have to be based on actual fact. ”  Assent to a proposition or affirmation, or the acceptance of a fact, opinion, or assertion as real or true, without immediate personal knowledge; reliance upon word or testimony; partial or full assurance without positive knowledge or absolute certainty; persuasion; conviction; confidence; as, belief of a witness; the belief of our senses a religious doctrine that is proclaimed as true without proof

(PhysOrg.com) -- Advances in cognitive neuroscience (the science of how the brain works when we think) have shown that what our eyes see and what our brain interprets are two different things. Professor Guillaume Thierry, Dr Panos Athanasopoulos and colleagues report in the prestigious journal Proceedings of the National Academy of Sciences USA that our language causes our brains to perceive colours differently.

To see whether language shapes our biological and physiological processes of colour perception, the researchers used a technique called event related brain potentials (ERPs). This technique tracks activity in the brain millisecond by millisecond.

Professor Thierry explains: “We know that the visual system in our brain begins processing stimuli like colour a few tens of milliseconds after light has hit the retina of the eye. We also know that language consciously invades our thinking about 200 milliseconds later. Using ERPs, we are able to look at very early stages of visual analysis, well before conscious language information is accessed.”

The researchers found differences in visual processing of light and dark blues between Greek and English speakers as early as 100 milliseconds, suggesting that indeed, speakers of different languages literally have differently structured minds.