More informations on perception itself as I realised that I’ve just went straight into the various types of perceptions in relation to illusions and colours. Sensation and Perception by E. Bruce Goldstein (Eighth Edition) is a book that covers various aspects of perceptions of which it includes the basics/introduction of it.

Perception is the ability to be aware of something through the senses and this experience is the result of “behind the scenes” processes of which determine our experience and reaction in the environment. The four processes are — Stimulus, Electricity, Experience & Action, Knowledge.

Stimulus

Things that stimulates our receptors and there are two kinds – in the environment and within a body. The environment stimulus is basically everything we can perceive within an environment while attended stimulus focuses on a particular thing of which it forms an image on the retina. This image then becomes a representation of that particular thing.

Electricity

Electric signals “created by the receptors and transmitted to the brain”. (Page 5) It transform energy such as light or mechanical pressure from the environment to the nervous system. This process is also known as transduction where transformation of energy from one form to another takes place. It is important for the signal to transmit to the brain in order to be able to perceive.

Experience & Action

Being able to “perceive, recognise and react to the stimuli”.

Knowledge

Any informations a “perceiver brings to a situation”(Page 9). This process is considered the most important among the rest due to its influential ability to categories objects from acquired knowledge. There are two kinds of processing — Bottom-up (Data-based) and Top-down (Knowledge-based). Bottom-up is basically incoming data of which usually provides as a starting point for perception. Top-down is based on knowledge and often one could be or not be aware of this process.

“Newton’s idea is that the colours that we see in response to different wavelengths are not contained in the rays of light themselves. Instead, these colours are created by our perceptual system as colour is not a property of wavelength but is the brain’s way of informing us what wavelengths are present.” (Page 206)

Thus, perceptual qualities such as colours are created by the nervous system instead.

Ted Talk by Beau Lotto, a Neuroscientist and Artist where he covered on Optical Illusion. At the near end of the video (15:00), he demonstrated his last experiment that left me questioning myself.

Some points noted:

• Colour enables us to see the similarities and differences between surfaces, according to the full spectrum of light that they reflect.
• Light that falls onto our eyes is determined by multiple things in the world, not only the colour of objects, but also their illumination and space between us and those objects. Thus, the vary in any one of those parameters change the colour of the light that falls onto your eye.
• Light that falls onto your eye, sensory information, is meaningless, because it could mean literally anything. There’s no inherent meaning in information, it’s what we do with that information that matters.