General Psychology, 4: Sensation and Perception

Question 1

Sensation vs. Perception

Answer 1

Sensation is the initial experience of a stimulus, whereas perception is a more complex representation of the world that involves combining various sensations

Question 2

Transduction

Answer 2

The process by which various forms of physical energy in the world are translated into neural signals; accomplished by sensory receptors

Question 3

Role of sensory receptors and neurons in sensation

Answer 3

Sensory receptors are specialized neurons that react to physical energy and emit neural impulses. Ordinary neurons cannot transmit the actual physical in the form of light, pressure waves, etc - the brain’s only representation of the world is in patterns of neural firing.

Question 4

Thalamus

Answer 4

The ‘sensory switchboard’ which processes virtually all incoming sensory signals, it organizes them and sends them to specialized cortical areas for finer processing.

Question 5

Absolute threshold

Answer 5

Minimum amount of physical energy required to produce a sensation. Varies from person to person and acros time within persons. Defined by the stimulus level at which a person detects the stimulus at least 50% of the time.

Question 6

Difference threshold

Answer 6

aka ‘just noticeable difference.’ The minimum amount of change in intensity of a stimulus required for a person to notice there has been a change. The person must detect a change 50% of the time to define their threshold.

Question 7

Signal Detection Theory

Answer 7

Method of measuring perceptions that allows a researcher to differentiate between the roles of discriminability and judgement. Notable for difference from psychophysics, which neglected the need for judgement in detecting stimuli.

Question 8

Visual receptors in the eye

Answer 8

Rods and cones, entirely located on the retina

Question 9

Retina

Answer 9

Rear wall of the eye, covered with visual receptors

Question 10

Optic nerve

Answer 10

Area where signals from rods and cones exit the retina along a bundle of nerves, creating a blind spot because there are no receptors on this part of the retina.

Question 11

Color blindness

Answer 11

Most common form is difficulty distinguishing red and green. There is also yellow/blue color blindness. It is usually genetic, resulting in a deficiency in or absence of one of the types of cones used for detecting color.

Question 12

Weber’s Law

Answer 12

As stimuli become more intense, the difference threshold increases at a constant rate.

Question 13

Accomodation (vision)

Answer 13

The process whereby muscles around the eye cavity change the shape of the lens to better focus. The les is flattened to focus on distant objects, and thickened to focus on nearby objects.

Question 14

Dorsal vs Ventral stream

Answer 14

Two theoretical parallel pathways for processing visual information. Roughly, the Ventral processes the “what,” dorsal the “where”. Dorsal and ventral are general anatomical directions corresponding to the posterior and the front of the body, respectively.

Question 15

Olfaction

Answer 15

Sense of smell. The only sense that bypasses the thalamus and is directly processed in the limbic system.

Question 16

Haptic

Answer 16

The haptic sense (aka touch) generates awareness of the position of limbs and the body in space, as well as sensations of hot/cold, pain, and pressure.

Question 17

Perception of color lightness vs brightness

Answer 17

Color brightness is defined by the absolute instensity of the light as it reaches the eye. However, stimuli with equal lightness may appear to have different brightness depending on the surrounding context. The contrast of a darker background makes colors appear lighter, a lighter context, the color appears darker.

Question 18

Occipital lobe

Answer 18

Part of the cortex specialized for processing visual information

Question 19

Temporal lobe

Answer 19

Part of the cortex specialized for processing auditory information, among other functions

Question 20

Agnosia

Answer 20

General term for the loss of ability to recognize objects, when there is no damage to the sensory systems involved.

Question 21

Prosopagnosia

Answer 21

A deficit in the ability to recognize faces but not other objects. Imaging studies reveal that for most people, faces are processed in the fusiform gyrus.