Chapter 3: Sensation and Perception

Sensation

The process of detecting a physical stimulus, such as light, sound, odors, and images.

Perception

The process of taking in, interpreting, and organizing information received from stimuli.

Sensory receptors

Specific cells attached to the senses that respond to sensory stimulation, both internal and external.

Threshold

The level of activation required for sensory receptors to respond to stimuli.

Absolute threshold

The smallest possible level of sensory stimuli that can be detected 50% of the time.

Difference threshold

The minimum threshold that a person can detect a noticeable difference 50% of the time.

Weber’s law

The principle stating that the more intense the stimulus, the greater the increase in stimulus intensity required to produce a just noticeable difference.

Transduction

The process of converting a stimulus into an electrical signal in the nervous system.

Sensory adaptation

The gradual decline in sensitivity to a constant stimulus, allowing attention to focus on new information.

Light

A stimulus for vision that travels in waves.

Accommodation

The lens's ability to focus on near and far objects.

Retina

A thin layer of tissue at the back of the eye that converts light into electrical signals for the brain.

Photoreceptors

Cells in the retina that process visual information; includes rods and cones.

Rods

Photoreceptors responsible for night vision, sensitive to low light, and do not detect color.

Cones

Photoreceptors that require more light and are used to see color; there are three types:blue, green, and red.

Fovea

A small area in the retina where cones are concentrated, aiding in sharpness and detailed images.

Optic disk

A part of the retina that lacks rods and cones, creating a blind spot in vision.

Ganglion cells

Specialized cells in the retina that process visual information before it is sent to the brain.