Perception part 1

Question 1

What is sensation?

Answer 1

The detection of physical energy by the sense organs, which then send information to the brain.

Question 2

What is perception?

Answer 2

The brains interpretation of raw sensory input.

Perception is how we know anything about our
world.

Question 3

How is sensation connected to perception?

Answer 3

The sensation is detected by the sensory organs then analysed by the brain to form a complete percept.

Question 4

What is transduction?

Answer 4

The process by which characteristics of a stimulus are converted into nerve impulses.

Question 5

What is top-down processing?

Answer 5

When a stimuli are perceived using prior knowledge about their characteristics.

Question 6

What is bottom-up processing?

Answer 6

When the sensation (stimulus) isn’t fully understood and is interpreted to form a complete idea (percept) of the stimulus.

Starts with small details, builds up to overall perception.

It is data driven; learning from what your sensations tell you.

Question 7

What is the role that attention has in perception?

Answer 7

Attention is when we focus our awareness on particular stimuli while ignoring (shadowing) the others. Conserves mental energy by focusing on what is deemed important.

Question 8

What is shadowing in the context of perception?

Answer 8

Shadowing is when a person’s attention, and therefore awareness, is shifted away from particular stimuli to focus on different stimuli.

The person is aware of these stimuli and can perceive them but chooses not to through their own volition: they’re shadowed.

Question 9

What is inattentional blindness?

Answer 9

The failure to perceive certain stimuli while attending to other stimuli.

The stimuli register in the nervous system but do not enter into the person’s awareness.

Question 10

What two factors affect a person’s attention to stimuli?

Answer 10

1. The nature of the stimulus (environmental)
2. Personal factors

Question 11

What are 3 characteristics of stimuli that effectively capture our attention?

Answer 11

1. Intensity
2. Novelty
3. Movement

Question 12

What are 2 person factors that influence our attention to stimuli?

Answer 12

Motives and Interests

Question 13

Change blindness

Answer 13

dunno

Question 14

What is involved in the process of perception?

Answer 14

Perception involves cognitive processes and memory.

It’s an Active and complex process.

It’s not necessarily deliberate/conscious.

Question 15

What are some practical applications of studying perception?

Answer 15

Awareness of perceptual failures can enhance
safety – e.g. improved sensory guidance for blind people.

Question 16

What are 2 other names for bottom-up processing?

Answer 16

1. Ecological perception
2. Direct perception

Question 17

What is an example of bottom-processing?

Answer 17

When you enter the cockpit of a UFO and there’s lots of unfamiliar technology that you’re trying to interpret.

Question 18

What is visual agnosia?

Answer 18

Agnosia = “not knowing”

Apperceptive visual agnosia: an abnormality in visual perception and discriminative process despite the visual stimuli being “clear”.

Some features can be recognised, e.g. shape, colour, but unable to combine them into a complete perception of the object.

Question 19

What are 2 symptoms of apperceptive visual agnosia?

Answer 19

1. Unable to recognize objects, draw, or copy a figure.
2. Cannot perceive correct forms of the object, although knowledge of the object is intact.

Question 20

What causes visual agnosia?

Answer 20

Lesions to the parietal, occipital cortex.

Question 21

What is Gibson’s Theory of Direct Perception (1966)?

Answer 21

Perception is innate rather than learned.

Information we need to form perceptions is contained in the environmental stimuli – e.g., texture gradient that is perceived as distance:

Paver stones in the pavement appear smaller at a distance, but they’re not smaller stones, they’re the same stones but further away.

Question 22

What is constructivism?

Answer 22

A part of top-down processing.

A process of taking fragments of information and constructing meaning.

The constructed percept isn’t always true: it’s an educated guess.

Question 23

What are schemas? Why are they important?

Answer 23

A schema, or schematic, is a mental framework that organises and synthesises information about learned stimuli.

Schema’s memorise information about all kinds of stimuli to save you from needing to consciously process them on re-encounters.

Question 24

Why does the brain prefer to use top-down processing over bottom-up processing?

Answer 24

Top-down processing uses less energy than bottom-up processing.

Question 25

What is psychophysics?

Answer 25

A scientific area of study which focuses on the relations between the physical characteristics of stimuli and sensory capabilities.

Question 26

What are the two kinds of sensitivity studied in psychophysics?

Answer 26

1. The absolute threshold

and

2. The difference threshold

Question 27

What is the absolute threshold?

Answer 27

The lowest intensity at which a stimulus can be detected at least 50% of the time.

Question 28

What are subliminal stimuli?

Answer 28

Very weak stimuli that a person isn’t aware of but is being unconsciously perceived.

Question 29

What is the difference threshold?

Answer 29

The smallest difference between two stimuli that people can perceive at least 50% of the time.

Question 30

What is another term for the difference threshold?

Answer 30

Just Noticeable Difference (JND)

Question 31

What is the signal detection theory?

Answer 31

The area of research that is concerned with determining the factors that influence sensory judgements.

Question 32

How is sensitivity to stimuli correlated to the absolute threshold?

Answer 32

There is a negative correlation: as sensitivity to stimuli increases, the absolute threshold decreases.

Question 33

Describe a sensory-detection matrix? How does it work?

Answer 33

Sensory-perception matrix or test:

                                           Stimulus
                  Present                                         Absent

‘yes’ Hit False alarm

‘no’ Miss Correct rejection

Question 34

What is Weber’s law?

Answer 34

Weber’s law states that the difference threshold, or JND, is directly proportional to the magnitude of the stimulus with which the comparison is being made.

Question 35

What is a Weber fraction?

Answer 35

The mathematical expression of Weber’s law

In determining the difference threshold for weights:

Weber’s fraction = 1/50

For a weight of 50 grams the just noticeable difference would be 51 grams