Psychology Chapter 5: The Visual System

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Questions and Answers

What is the function of receptors in our senses?

To convert light into sound

To perceive sights, sounds, smells, etc.

To transmit signals directly to the brain

To transduce energy into electrochemical patterns (correct)

What is the law of specific nerve energies?

That neurons can respond to multiple types of energy

That nerve activity is random and unpredictable

That the brain can perceive multiple types of energy simultaneously

That different neurons always convey the same type of information to the brain (correct)

What determines what we perceive?

The type of neuron, amount of response, and timing of response (correct)

The intensity of the stimulus only

Only the amount of response

Only the type of neuron responding

What type of energy are receptors for vision sensitive to?

Light Signup and view all the answers

What is the main limitation of the opponent-process and trichromatic theories?

Color constancy Signup and view all the answers

What is the function of the brain in perception?

To interpret electrochemical patterns from receptors Signup and view all the answers

What is the role of electrochemical patterns in perception?

They are the signals sent from receptors to the brain Signup and view all the answers

What theory compares information from various parts of the retina to determine brightness and color?

Retinex theory Signup and view all the answers

What percentage of men have a color vision deficiency?

~8% of men Signup and view all the answers

Which of the following is NOT a theory of color vision?

Color vision deficiency Signup and view all the answers

On which chromosome is the gene responsible for color vision deficiency located?

X chromosome Signup and view all the answers

What do the Retinex, trichromatic, and opponent-process theories all attempt to explain?

Color perception Signup and view all the answers

What is the name of the opening in the center of the iris?

Pupil Signup and view all the answers

What is the role of the lens and cornea in the eye?

To focus light Signup and view all the answers

What is the name of the surface at the back of the eye that is lined with visual receptors?

Retina Signup and view all the answers

Which part of the retina receives light from the left side of the world?

Right side of the retina Signup and view all the answers

What type of cells send messages to ganglion cells in the eye?

Bipolar cells Signup and view all the answers

What is formed by the axons of ganglion cells joining together?

Optic nerve Signup and view all the answers

Where do the ganglion cells send their messages?

Brain Signup and view all the answers

What is the function of visual receptors in the retina?

To detect light Signup and view all the answers

What determines the color according to the trichromatic theory?

The ratio of activity across the three types of cones Signup and view all the answers

What is a limitation of the trichromatic theory?

It cannot explain color afterimages Signup and view all the answers

What is the mechanism of the opponent-process theory?

Bipolar cells are excited by one set of wavelengths and inhibited by another Signup and view all the answers

According to the opponent-process theory, how do we perceive color?

In terms of paired opposites Signup and view all the answers

What is an example of a color pair in the opponent-process theory?

Red and green Signup and view all the answers

What is the effect of more intense light on the color according to the trichromatic theory?

It increases the brightness of the color but does not change the ratio Signup and view all the answers

How many types of cones are involved in the trichromatic theory?

Three Signup and view all the answers

What is a characteristic of each cone in the trichromatic theory?

Each cone responds to a broad range of wavelengths, but some more than others Signup and view all the answers

What is the function of amacrine cells in the eye?

To control the ability of ganglion cells to respond to visual stimuli Signup and view all the answers

What is the purpose of the optic nerve?

To transmit visual information from the eye to the brain Signup and view all the answers

Where do the axons of ganglion cells band together to form the optic nerve?

At the back of the eye Signup and view all the answers

What is the term for the point at which the optic nerve leaves the back of the eye?

Blind spot Signup and view all the answers

What type of cells do amacrine cells receive information from?

Bipolar cells Signup and view all the answers

What is the function of amacrine cells in controlling the response of ganglion cells?

To control the ability of ganglion cells to respond to shapes, movements, or other specific aspects of visual stimuli Signup and view all the answers

What happens to the axons of ganglion cells as they exit the eye?

They band together to form the optic nerve Signup and view all the answers

What is the significance of the blind spot in the eye?

It contains no receptors Signup and view all the answers

Study Notes

General Principles of Perception

Each of our senses has specialized receptors that are sensitive to a particular kind of energy.
Receptors for vision are sensitive to light.
Receptors "transduce" (convert) energy into electrochemical patterns so that the brain can perceive sights, sounds, smells, etc.
The law of specific nerve energies states that activity by a particular nerve always conveys the same type of information to the brain.
Which neurons respond, the amount of response, and the timing of response influence what we perceive.

The Eye and Its Connections to the Brain

Light enters the eye through the pupil.
Light is focused by the lens and the cornea onto the rear surface of the eye, known as the retina.
The retina is lined with visual receptors.
Light from the left side of the world strikes the right side of the retina and vice versa.
Visual receptors send messages to neurons called bipolar cells.
Bipolar cells send messages to ganglion cells that are even closer to the center of the eye.
The axons of ganglion cells join one another to form the optic nerve that travels to the brain.
Amacrine cells are additional cells that receive information from bipolar cells and send it to other bipolar, ganglion, or amacrine cells.
Amacrine cells control the ability of the ganglion cells to respond to shapes, movements, or other specific aspects of visual stimuli.

Color Vision

The trichromatic theory explains that:
- Each cone responds to a broad range of wavelengths, but some more than others.
- The ratio of activity across the three types of cones determines the color.
- More intense light increases the brightness of the color but does not change the ratio.
The opponent-process theory suggests that:
- We perceive color in terms of paired opposites.
- The brain has a mechanism that perceives color on a continuum from red to green and another from yellow to blue.
- A possible mechanism for the theory is that bipolar cells are excited by one set of wavelengths and inhibited by another.
The Retinex theory suggests that the cortex compares information from various parts of the retina to determine the brightness and color for each area.
Color vision deficiency is an impairment in perceiving color differences, and the gene responsible is contained on the X chromosome (~8% of men).

The Optic Nerve

The optic nerve consists of the axons of ganglion cells that band together and exit through the back of the eye and travel to the brain.
The point at which the optic nerve leaves the back of the eye is called the blind spot because it contains no receptors.

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Description

This quiz covers the general principles of perception, including the specialized receptors for each sense, and the process of vision and light sensitivity.