Sensation & Perception Studyguide

Proprioception

A human sensory ability that helps in the awareness of body position and movement.

Absolute threshold

The smallest amount of a stimulus necessary to allow an observer to detect its presence.

Cones

The part of the eye that needs plenty of light to function properly.

Optic Chiasm

The structure where information from the right side of both eyes is sent to the left hemisphere.

Method of Adjustment

A technique in which an observer adjusts the level of pressure on the skin until it can just barely be felt.

Astigmatism

A condition resulting from an irregular shape of the cornea or lens, affecting the ability to focus images.

Sensation

The registering of a physical stimulus on our sensory receptors.

Difference Thresholds

The smallest differences in the wavelength of light that humans can detect.

Purkinje shift

The observation that short wavelengths appear brighter than long wavelengths in low light conditions.

Rod system

The receptor system associated with scotopic vision.

Signal detection theory

A framework that analyzes how decisions are made under conditions of uncertainty.

Fovea

The area of the retina with the highest acuity and densest concentration of cones.

Ocular dominance column

A column in V1 made up of neurons that receive input exclusively from one eye.

Perspective Projection

The visual phenomenon where objects appear smaller when farther away.

Transduction

The process of converting physical energy into a neural signal.

Accommodation

The adjustment of the lens of the eye to focus on near and far objects.

Weber's Law

A principle stating that the smallest detectable difference in stimulus intensity is a constant proportion of the original stimulus.

Forced-choice method

A psychophysical method requiring participants to report when or where a stimulus occurs.

Dorsal Stream

The part of the brain responsible for detecting where an object is in the visual field.

Fovea

The part of the retina that receives detailed visual input.

Retinotopic organization

The mapping of visual input from the retina to neurons in the brain in a spatially organized manner.

Point of subjective equality

The point at which subjective estimates of a stimulus correspond to objective measures.

Blind spot

The point in the visual field where no photoreceptors are present, yet not perceived as a gap.

Light adaptation

The process of reducing visual sensitivity in response to higher light levels.

False alarm

A mistake made when an observer claims to detect a stimulus that is not present.

On-center receptive fields

Retinal ganglion cells that exhibit excitation when light is presented in the center of their receptive field.

Difference threshold

The smallest difference between two stimuli that can be detected.

Photoreceptors

Sensory receptors in the eye specialized to respond to light.

Visual processing

The complex procedure involving the transition from sensory input to perceptual output.

Pupil

The eye structure that contracts or expands in response to lighting conditions.

Threshold and sensitivity

A lower threshold means higher sensitivity; stimuli can be detected at weaker intensities.

Rods

Photoreceptors in the retina specialized for night vision.

Signal Detection Theory

A theory assessing the ability to differentiate signals from noise in perceptual tasks.

Sensitivity

A measure of how easily a task can be performed based on the rates of correct detections and misses.

Simple Cell

responds to a specific orientation of a stimulus only at a precise location within its receptive field.

Complex Cell

can detect the same orientation regardless of its position within the receptive field.