1: Introduction to Perception

Question 1

What is distal stimulus? Proximal stimulus?

Answer 1

Distal: “distant”
Proximal: “in proximity” to receptors

Question 2

What is principle of transformation? Principle of representation?

Answer 2

Transformation: stimuli and re­sponses created by stimuli are transformed, or changed, between the distal stimulus and perception.

Representation: everything person perceives based not on direct contact with stimuli but on representations of stimuli that are formed on the receptors and the resulting activity in the person’s nervous system.

Question 3

When visual receptors that line the back of the eye receive light, they do what two things?

Answer 3

Transform environmental energy into electrical energy.

Shape perception by the way they respond to different properties of stimuli.

Question 4

Visual receptors transform light energy into electrical energy because they contain a light-sensitive chemical called what?

Answer 4

Visual pigment.

Question 5

What is transduction?

Answer 5

Transformation of one form of energy (light energy) to another form (electrical energy).

Question 6

What are the primary receiving areas for vision, hearing, and skin senses? What lobe receives signals from all the senses?

Answer 6

Vision: occipital
Hearing: temporal
Skin senses: parietal
Signals from all senses: frontal

Question 7

Distinguish between perception and recognition.

Answer 7

Perception: conscious awareness
Recognition: placing object in a category (e.g. “tree”)

Question 8

What vision disorder marks the inability to recognize objects?

Answer 8

Visual form agnosia.

Question 9

What is the oblique effect?

Answer 9

People see vertical or horizontal lines better than lines oriented obliquely (at any orientation other than vertical or horizontal).

Question 10

What are the three relationships pertinent to psychophysics?

Answer 10

Stimulus-perception relationship
Stimulus-physiology relationship
Physiology-perception relationship

Question 11

What is grating acuity and what relationship does it demonstrate?

Answer 11

Smallest width of lines that subjects can detect. Demonstrates stimulus-perception relationship.

Question 12

Knowledge, memories, and expectations are described as what factors?

Answer 12

Cognitive influences on perception.

Question 13

What are thresholds?

Answer 13

Measure limits of sensory systems; measures of minimums.

Question 14

Fechner proposed that the mind could be studied by measuring what?

Answer 14

The relationship between changes in physical stimulation and a person’s experience.

Question 15

Fechner’s proposal is based on what observation?

Answer 15

By increasing the intensity of a light, the person’s perception of the brightness of the light also increases.

Question 16

Describe the method of limits.

Answer 16

Presents stimuli in either ascending order (intensity is increased) or descending order (intensity is decreased).

Detect tone = crossover
Threshold = average of crossovers

Question 17

Describe the method of adjustment.

Answer 17

Stimulus intensity is adjusted continuously until observer detects it.

Repeated trials averaged for threshold.

Question 18

Describe the method of constant stimuli.

Answer 18

Several stimuli of different intensities are presented in random order, multiple trials presented.

Threshold is the intensity that results in detection in 50% of trials.

Question 19

What are absolute thresholds and difference thresholds?

Answer 19

Absolute threshold: smallest stimulus level that can be detected.

Difference threshold: smallest difference between two stimuli that enables us to tell the difference between them.

Question 20

What is Weber’s Law?

Answer 20

DL / s = k

DL = difference threshold
s = standard stimulus
k = Weber fraction

For a given stimulus, measure Weber fraction (DL / s).
With known Weber fraction and a new stimulus, calculate DL (k x s).

Question 21

The function that shows how the threshold becomes smaller as the person spends more time in the dark is called what?

Answer 21

Dark adaptation curve.

Question 22

What is magnitude estimation?

Answer 22

Observer is given a standard stimulus and a value for its intensity, compares the standard stimulus to test stimuli by assigning numbers relative to the standard.

Question 23

What is response compression? Response expansion?

Answer 23

Response compression: Intensity increases, perceived magnitude increases more slowly than intensity.

Response expansion: Intensity increases, perceived magnitude increases more quickly than intensity.

Question 24

Describing what is out there is called…

Answer 24

Phenomenological report.

Question 25

What parts of the electromagnetic spectrum are we able to perceive?

Answer 25

400nm - 700nm