PSYCH 104 Midterm 2 (sensation and perception)

Question 1

Sensation

Answer 1

• Sensation
  ○ The process by which (objective) stimuli are detected, transduced into nerve impulses and sent to the brain

Question 2

Perception

Answer 2

• Perception
  ○ The brains interpretation of raw sensory inputs

Question 3

Transduction

Answer 3

• Transduction
  ○ The process of converting an external energy or substance into electrical activity within neurons

Question 4

Sense receptor

Answer 4

• Sense receptor
  ○ Specialized cell responsible for converting external stimuli into neural activity for a specific sensory system

Question 5

Sensory adaptation

Answer 5

• Sensory adaptation
  ○ Activation is greatest when a stimulus is first detected and then declines in responsiveness
  ○ Also called neural adaptation

Question 6

Psychophysics

Answer 6

• Psychophysics
  ○ The study of how we precieved sensory stimuli based on their physical characteristics

Question 7

Absolute threshold

Answer 7

• Absolute threshold
  § Lowest level of a stimulus needed for the nervous system to detect a change 50 percent of the time
  ○ Just noticeable difference (JND)
  § The smallest change in the intensity of s stimulus we can detect
  ○ Weber’s law
  § There is a constant proportional relationship between the JND and original stimulus intensity
  § I = intensity of the stimulus
  § K = constant

Question 8

JND

Answer 8

JND: the louder the volume is, the greater the change in volume that is needed to detect a difference

Question 9

JND (Formula)

Answer 9

JND = K x I
§ I = intensity of the stimulus
§ K = constant (0.10)

Question 10

Signal detection theory

Answer 10

Signal detection theory
- Asks two questions
○ Was waldo in the image?
○ Did you say waldo was in the image?

Question 11

Signal

Answer 11

Signal = stimulus to be perceived

Question 12

Signal detection theory (Noise)

Answer 12

Noise = everything else

Question 13

What does Increased sensitivity to the signal cause?

Answer 13

Increased sensitivity to the signal causes hits and correct rejections to occur more often

Question 14

What does Decreased sensitivity to the signal cause?

Answer 14

Decreased sensitivity to the signal causes misses and false alarms to occur more often

Question 15

How are differences in sensitivity measured?

Answer 15

Differences in sensitivity are measured with a statistic called D-prime
- A measure of the stimulus salience
- Plotted using ROC curves (Receiver operating characteristic curves)

Question 16

What does a perfect signal detection theory test do?

Answer 16

A perfect test hugs the Y axis
- You want the curve to bend as close to the top left curve as possible

Question 17

Police line ups accuracy?

Answer 17

Police lineups accuracy
- One by one: 30% accurate
- All at once: 39% accurate
- The false alarm rate is higher in the all at once

Question 18

What do police line ups show us?

Answer 18

This shows us that the simultaneous method is better than the sequential but it is barely noticeable

Question 19

What do polygraphs need to be accurate?

Answer 19

Polygraphs: they actually need to be set in terms off sensitivity un order to administer the test

Question 20

What is the issue with polygraphs?

Answer 20

They are more correct than not but they also make many false positives

Question 21

Perception

Answer 21

Perception
- Perception is determined by three basic elements
○ What is currently being sensed
○ What was sensed
○ What has happened in the past

Question 22

Perception - Parallel processing

Answer 22

• Parallel processing: the ability to attend to many sense modalities simultaneously

Question 23

Perception - Bottom up processing:

Answer 23

• Bottom up processing: processing in which a whole is constructed from its parts

Question 24

Perception - Top-down processing

Answer 24

• Top-down processing: conceptually driven processing influenced by beliefs and prior learning

Question 25

Perceptual set

Answer 25

Perceptual set: A set formed when expectations influence perceptions

Question 26

Perceptual constancy

Answer 26

Perceptual constancy: the process by which we perceive stimuli consistently across varied conditions

Question 27

What is the disclaimer about perceptual sets?

Answer 27

A disclaimer: perceptual sets and constancy are just concepts which describe patterns of behavior in relation to sets of stimuli - They do not provide an explanation of that pattern of behavior

Question 28

Attention - Selective attention

Answer 28

- Selective attention ○ The process of selecting one sensory channel and ignoring or minimizing others § Assumed to be controlled by the reticular activating system (RAS) and higher cortical regions

Question 29

Attention - Filter "theory" of attention

Answer 29

- Filter "theory" of attention ○ Attention is a 'bottle neck' through which information passes § Dichotic listening: a research design in which subjects have a message delivered to each ear independently through headphones. Both messages are delivered simultaneously, but only the attended ears message is able to be accurately recalled

Question 30

Inattentional blindness

Answer 30

Inattentional blindness - Failure to detect stimuli that are in plain sight when our attention is focused elsewhere

Question 31

Change blindness

Answer 31

- Change blindness ○ Failure to detect changes in a visual stimulus

Question 32

Subliminal messaging

Answer 32

Subliminal messaging: putting messages into music or other broadcasts that we observe and interpret unconsciously - It can also be noted that it does not work and that has been proven numerous times over

Question 33

Extrasensory perception (What is it?)

Answer 33

Extrasensory perception - Perception of events outside the known channels of sensation

Question 34

Extrasensory perception - Precognition

Answer 34

○ Precognition § Predicting events before they occur though paranormal means □ Eg. What cards will appear

Question 35

Extrasensory perception - Telepathy

Answer 35

○ Telepathy § Reading others minds

Question 36

Extrasensory perception - Clairvoyance

Answer 36

○ Clairvoyance § Detecting the presence of objects that are hidden from view

Question 37

Zener cards

Answer 37

Zener cards: used to test precognition, telepathy, and clairvoyance - Used by Rhine

Question 38

Zenner cards results of the Rhine tests?

Answer 38

<-- the results of the tests ○ They were higher than expected

Question 39

How large must a group of people be before the probability of two people sharing the same birthday exceeds 50%?

Answer 39

§ A: 23