Chapter 1

Question 1

What is sensation?

Answer 1

The stimulation of sensory organs (ex: light entering the eye, sound waves entering the ear)

Question 2

What is perception?

Answer 2

The organization of sensory info into representations of the physical stimulus (ex: seeing the colour red, recognizing a voice)-essentially the QUALITATIVE experience.

Question 3

Rods fire more quickly when…

Answer 3

They are exposed to light things

Question 4

What is a metamer?

Answer 4

Something that is physically different than another thing, but they look the same (ex: two colours being perceived differently, but in the end are the same colour)

Question 5

What are senses?

Answer 5

Physiological functions with specialized cells to convert an environmental feature into a neural signal.

Question 6

What are the steps in the perceptual process? (NEEDS EDITING)

Answer 6

1. Environmental stimuli 2. Transduction 3. Neural processing

Question 7

What is the difference between distal and proximal stimuli?

Answer 7

Distal: The thing out in the world (ex: a piano). Proximal: The thing that impinges on sensory receptors. (Ex: The sound of the piano playing)

Question 8

What is transduction?

Answer 8

Translation of the proximal stimulus into neural signals (sensation—> perception).

Question 9

What is the Principle of Neural Representation?

Answer 9

All that we perceive is NOT based on direct contact with the stimulus, but on representation (neural codes) in the receptors and brain.

Question 10

What happens in the brain when you imagine something vs actually perceiving the same thing?

Answer 10

The same neural circuits are used (ex: if you see a tree vs if you imagine a tree).

Question 11

What is neural processing?

Answer 11

Combination of information from different receptors within a sense (ex: RGB cones firing rate is combined into a single percept of “yellow”.

Question 12

What is the Primary Receiving Area?

Answer 12

Where signals from each sense go, it is the first are that the sense sends it’s signal to.

Question 13

Can things be combined across the senses?

Answer 13

YES. ex) Playing the piano combines visual, auditory, and tactile signals.

Question 14

What is bottom-up processing?

Answer 14

Processing based on the stimuli reaching the receptors. Mainly about PATTERNS.

Question 15

What is top-down processing?

Answer 15

An observers knowledge, expectations and goals-all of which affect perception.

Question 16

What is psychophysics, and who is one of the main psychophysicists?

Answer 16

Studies the relationship between physical stimuli and the psychological experience (perception/behaviour). Gustav Fechner

Question 17

What is absolute threshold and how is it studied?

Answer 17

The minimum stimulus intensity that can just be detected-asks what is the limit to our senses? Traditionally studied using classical psychophysical methods.

Question 18

What are the three main classical psychophysical methods?

Answer 18

1) Method of Limits. 2) Method of Adjustment 3) Method of Constant Stimuli

Question 19

What is the method of limits and how accurate is it?

Answer 19

The method of limits presents the subject with a stimulus of given intensity and asks whether it’s detected or not. Experimentor then increases/decreases the intensity by set increments, and records when the response changes. The procedure then repeats in the other direction from a different set intensity. This method is relatively quick and relatively accurate.

Question 20

What is the method of adjustment and how accurate is it?

Answer 20

Subject adjusts the intensity of the stimulus themselves, after starting with a given intensity. This method is the fastest but the least accurate.

Question 21

What is the method of constant stimuli and how accurate is it?

Answer 21

5-9 stimuli of “constant” intensities are repeatedly presented in random order. The key to this one being the most accurate (yet the most time consuming) is that the intensities are random.

Question 22

What was the new definition of absolute threshold and why was it given?

Answer 22

Lowest intensity necessary for certain stimuli to be detected 50% of the time. It was created because researchers discovered that there was a gradual increasand not a sudden jump in what people could perceive/not perceive.

Question 23

What is adaptive testing?

Answer 23

A new way to measure absolute threshold. The next value depends on the participant’s response. An example is the staircase method, which builds off the method of limits BUT after each change in response, the direction switches but does not go to a brand new value.

Question 24

What is the difference threshold?

Answer 24

AKA just-noticeable difference. The smallest difference between 2 stimuli that people can detect 50% of the time.

Question 25

What is Weber’s law?

Answer 25

The size of the JND is proportional to the magnitude of the first stimulus. As a stimulus gets more intense, the difference must also increase for us to perceive it.

Question 26

What does having a lower threshold mean?

Answer 26

We are MORE sensitive to the stimulus.

Question 27

What is psychophysical scaling?

Answer 27

Asks whether perception matches sensation-if we increase a simulus 2 times, does the sensation of it also increase the same amount?

Question 28

What is response compression vs response expansion?

Answer 28

Response Compression- When a constant increase in a stimulus produces smaller and smaller perceptions of the intensity (brightness)
Response expansion- When a constant increase in stimulus produces a larger and larger intensity (shock).

Question 29

What is Steven’s Power Law?

Answer 29

An equation to determine the relationship between the physical and perceived intensity: P=KS^n.
If n<1= response compression, if n=1, then the line is linear, if n>1, then response expansion.

Question 30

What is one problem with psychophysical scaling?

Answer 30

Some people always claim to perceive the stimulus-which gives two very different absolute threshold curves.

Question 31

What is signal detection theory?

Answer 31

A solution to the problems with psychophysical scaling. Realizes that detecting stimuli involves not only perception, but also a decision, and sets a decision criterion.

Question 32

What is the method of signal detection theory?

Answer 32

Sometimes the stimulus is there, and sometimes it isn’t. People must say whether or not they detected it.

Question 33

What are the four parts of signal detection theory?

Answer 33

Hit- Stimulus is present, person says it’s present.
False Alarm- Stimulus is absent, person says its present
Miss- Stimulus is present, person says its not
Correct rejection-stimulus is not there, person says its not.

Question 34

What are some influences on threshold other than the actual stimulus?

Answer 34

Personality of the participant (risk-taker, vs not), fatigue/attention, rewards/cost, “noise.”