3 - sensation and perception lecture

Question 1

what is sensation?

Answer 1

the detection of simple properties of stimuli

Question 2

via what does sensation occur?

Answer 2

via our sensory organs — send information about the world to our brains

Question 3

stimuli may be _____ or _____ events?

Answer 3

distant or proximal

Question 4

what are the 5 sensory modalities?

Answer 4

• gustation (taste)
• olfaction (smell)
• vision
• audition
• somatosensation

Question 5

what are the somatosensory senses?

Answer 5

• detection of touch
• thermoception (temp)
• vestibular sense (balance)
• proprioception (internal feedback from muscles)
• nociception

Question 6

the detection of checmial signals (+other signals like sounds, light, touch) happens via what?

Answer 6

signal transduction

Question 7

smell is detecting different __________?

Answer 7

shaped molecules

Question 8

what is transduction?

Answer 8

any process by which a signal or stimulus is converted to another type of signal

Question 9

what is sensory transduction?

Answer 9

energy from environment is converted into neural activity

• stimulus in form of energy
• sense organs detect presence of environmental stimuli
• transmits info about stimuli via action potentials carried by the axons in sensory nerves

Question 10

action potentials are fixed in terms of what?

Answer 10

size and duration

Question 11

describe anatomical coding

Answer 11

• different nerves represent different modalities
• distinctions between stimuli of the same modality (eg. arising from different locations)
  eg. touch receptors in skin in different sports of body send info to different parts of primary somatosensory cortex

HOMONCULUS : larger representation = more sensitive

Question 12

describe temporal coding

Answer 12

• rate of firing of axons represents (‘encodes’) stimulus intensity
• more intense = higher firing rate
• AP itself cant be changed
• used by all sensory systems

Question 13

what is absolute threshold?

Answer 13

minimum level of a stimulus that can be detected

Question 14

what is the signal detection theory?

Answer 14

level at which stimulus will be detected a % of the time

Question 15

what is difference threshold?

Answer 15

minimum detectable difference between 2 stimuli / just notable difference

Question 16

detecting a stimulus involves discriminating between a ____ and _____?

Answer 16

between stimulus and noise

Question 17

what is perception?

Answer 17

our interpretation of what is represented by sensory input

Question 18

describe perception

Answer 18

• recognition of objects, sounds, people etc
• occurs unconsciously, but can be infused by higher-level cognitive processes such as expectations

Question 19

how do we differentiate figure from ground?

Answer 19

boundaries : sharp distinct changes in brightness, colour and patterns

Question 20

what is gestalt psychology?

Answer 20

• foundation for modern study of perception
• the whole is greater than the sum of its part

Question 21

what is the gestalt ground principle?

Answer 21

people instinctively perceive objects as either being in the foreground or the background

Question 22

what is the gestalt principle of grouping?

Answer 22

elements of a visual scene that are close to each other appear to form groups

Question 23

what is the gestalt principle of similarity?

Answer 23

similar elements are perceived as belonging together

Question 24

what is the gestalt principle of good continuation?

Answer 24

elements that smoothly follow a line tend to belong together

Question 25

what is the gestalt law of closure principle?

Answer 25

missing information is supplied to close or complete a figure

Question 26

what is the gestalt principle of common fate?

Answer 26

elements on the same movement trajectory belong together

Question 27

form perception : how does the brain recognise objects so quickly?

Answer 27

1. TEMPLATES = stored visual memories of patterns compared with visual input — brain sorts through templates to find exact match, image compared against internal representation 2. PROTOTYPES = flexible, idealised stored patterns compared with visual input — not exact match needed 3. FEATURE DISTINCTION MODELS = distinctive features model, geons — visual system encodes images of familiar patterns, in terms of distinctive features of geons

Question 28

what does perception require and sensation doesn’t?

Answer 28

existing knowledge

Question 29

what is perception influenced by?

Answer 29

- previous experience - assumptions - expectations - cultural factors - mood - attention

Question 30

what is perceptual set?

Answer 30

- selectively bias with respect to what we perceive - predisposed to perceive things in a certain why

Question 31

what is attention?

Answer 31

allocation of awareness to a stimulus

Question 32

describe selective attention

Answer 32

- our capacity for conscious processing of information is limited - selective attention is responsible for allocating this limited resource of awareness

Question 33

describe attention

Answer 33

- operates across sensory modalities and within our thoughts/memories - can be shifted consciously or unconsciously - the focus of attention can be broad or narrow