In: Psychology
1. Top-down perception- When the perception of a new stimulus or reality of new perception is based on prior experiences and stored information. In this processing, a person first perceives the whole stimulus and then interpret its parts if needed.
Bottom-up perception- Here information is carried in one direction from the retina to the visual cortex. This concept explained by Gibson through the direct theory of perception, in which he said what we see is what we get from the environment. So, people first get information from environment then form belief, experiences, and memory on the basis of the given information. Here, people first, perceive individual parts of a stimulus and then organize them as whole if possible.
2. Light- It is the electromagnetic radiation in the section of the electromagnetic spectrum that can be perceived by the human eye.
Colour- It is the perception of light, how we are perceiving the light waves coming in the eyes after reflecting surfaces of objects. Various colours depending on the wavelength of the light.
3. There are several parts of eyes such as Iris, Pupil, Lens, Retina, Cornea, Optic nerve, Rodes, Cones, etc. but here I am going to discuss four parts of eyes-
Iris- It is the coloured part of eye. It helps to adjust size of the pupil to control the amount of light enters into the eye. It also helps to focus on the object.
Retina- It is the light-sensitive layer at the back of the eye. It consists of three layers- Ganglion layer, bipolar layer and photoreceptors(rods and cones).
Lens- It is the clear structure that helps to focus on objects by visual accommodations.
Cornea- It is the clear membrane that covered eye. It protects the eye and also focuses on the light coming into the eye.
4. Rods and cones are the photoreceptor cells. They are responsible for different aspects of vision. Cones are sensitive to different wavelengths of light, so they are responsible for color vision but rides are sensitive for change in brightness not for wavelength so they perceive black and white.
5. Transduction- It is the process in which the physical energy of a stimulus is converted into neural signals/ nerve impulse or action potential. This physical stimulation receives from taste, touch, smell, vision, and hearing to convert into neural impulse.