Chapter 5: Sensation and Perception

Question 1

Sensation

Answer 1

• The detection of physical energy emitted or reflected by physical objects.
• Occurs when energy in the external environment or the body stimulates receptors in the sense of organs.

Question 2

Perception

Answer 2

Process by which the brain organizes and interprets sensory information.

Question 3

What are separate sensations?

Answer 3

• Specialized cells that convert physical energy in the environment or the body to electrical energy that can be transmitted as nerve impulses to the brain.
• Dendrites of sensory neuron’s responsible for smell, pressure, pain, and temperature.
• Specialized cells for vision, hearing, taste

Question 4

What is synthesia?

Answer 4

Sensory crossover from one modality to another can sometimes occur

In synthesia, sensation in one modality consistently evokes a sensation in another.

A person with synthesia may say things like:
The colour purple smells like a rose
The aroma of cinnamon feels like velvet
The sound of a note on a clarinet tastes like cherries

• The neurological basis of synesthesia is uncertain.

Question 5

Psychophysics

Answer 5

Filed concerned with how the physical properties of stimuli are related to our psychological experience of them.

Commonly relies on measuring absolute threshold, difference threshold, and applying signal-detection theory.

Question 6

Absolute Threshold

Answer 6

The smallest quantity of physical energy that can be reliably detected by an observer (50% of the time).

Senses are sharp, but only turned into narrow band of physical energies.

EX. When it goes from nothing, to something. Ex. volume from 0 to 1

Question 7

Difference Threshold

Answer 7

The smallest difference in stimulation that can reliably be detected by an observer when two stimuli are compared.

Also called just noticeable difference (JND)

Ex. volume between 19 and 20

Question 8

Weber’s Law

Answer 8

When it’s harder to tell the difference between volume at 30 and 35 than it is between 5 and 10.

Question 9

Signal Detection Theory

Answer 9

Divides the detection of sensory signals into a sensory process and a decision process.

Question 10

Sensory Adaptation

Answer 10

Reduction or disappearance of sensory responsiveness when stimulations is unchanging or repetition (habituation).
Useful as it spares us from responding to unimportant information.

Ex. Swimming, night vision, adapting to senses like food, smelly room

Question 11

Sensory Deprivation

Answer 11

Focusing of attention on selected aspects of the environment and blocking out the others.

Useful skill for young children who are in classrooms (e.g., working in groups blocking out noise from other classrooms, children)

Question 12

Inattentional Blindness

Answer 12

Failure to consciously perceive something you are looking at because you are not attending to it.

Ex. Opening the fridge and looking right at something and not seeing it.

Question 13

Vision

Answer 13

Light stimuli (waves) have physical characteristics that affect three psychological dimensions of our visual world: Hue, Brightness, Saturation

Question 14

Hue

Answer 14

Dimension of visual experience specified by colour names.
- Related to the wavelength of light.

Question 15

Brightness

Answer 15

Dimension of visual experience related to the amount of light emitted from or reflected by an object.
- Related to amplitude of wavelength.

Question 16

Saturation

Answer 16

Dimension of visual experience related to the complexity of light waves.
- Vividness or purity of colour.

Question 17

Feature Detector Cells

Answer 17

Cells in the visual cortex that are sensitive to specific features of the environment (faces, shapes).

Question 18

Trichromatic Theory

Answer 18

Proposes that three types of cones are sensitive to a certain range of wavelength (red, blue, green) (RBG. These are the values that produce different colours).
- Interaction in three cones produces the different experience of hue.

Question 19

Colour Blindness

Answer 19

typically a generic variation causing the absence or dysfunction of one or more of the cones.

Most are “colour deficient” meaning the person is unable to distinguish red and green (see everything as blue, yellow, brown, and grey).

Question 20

Opponent-Process Theory

Answer 20

Assumes that the visual system treats pairs of colours as opposing or antagonistic.
Occurs in the ganglion cells, and neurons in the thalamus and visual cortex.
Three opponent pairs: red/green; blue/yellow; black/white
Cells that are inhibited by one colour, produce burst of firing when opponent colour presented.

Question 21

Negative Afterimage

Answer 21

Occurs when you see the inverse colour of the original photograph. An example of this is when you stare at a red image for a period of time and when you look away you should see a green afterimage.

Question 22

What are the Gestalt principles?

Answer 22

Proximity: things near each other tend to be grouped together.

Closure: the brain fills in gaps to perceive complete forms.

Similarity: things that are alike are perceived together

Continuity: lines and patterns tend to be perceived as continuing in time or space

Question 23

Perceptual Constancy

Answer 23

The accurate perception of objects as stable or unchanged despite changes in the sensory patterns they produce.
- Best-studied are shape, location, size, brightness, and colour constancies.

Question 24

Binocular cues

Answer 24

Used for objects that are fairly close to us.

Our eyes converge (turn inward) when we focus on an object that is close to us.

Question 25

Monocular cues

Answer 25

Used when objects are far away.

Monocular cues are visual cues to depth or distance that can be used by one eye.

Question 26

Perceptual Illusions

Answer 26

give us information about perceptual strategies used by brain, and how misleading messages are interrupted.

Question 27

Sound Localization

Answer 27

relies on loudness and intensity of stimuli to tell us where a sound is coming from.

Question 28

5 Main Tastes (Gustation)

Answer 28

salty, sour, bitter, sweet, umami (pleasant savoury taste - breastmilk, tomatoes, fish).

Question 29

Supertasters

Answer 29

Individuals who have more taste buds, and smalled papilla.
- Find some foods unpleasantly bitter.

Question 30

Smell (Olfaction)

Answer 30

Smell is important in detecting danger (smoke, food spoilage, gas leak, etc.).
Sense of smell sometimes lost through infection, disease, injury, or smoking.
Smokers (2 packs/day) must abstain 10 years for smell to return to normal.

Psychological effects of smell include evoking memories and emotions but may also include evoking behaviours.

Question 31

Basic skin senses?

Answer 31

Touch (pressure), warmth, cold, pain.
Certain spots on skin especially sensitive to 4 basic sensations.

Question 32

How does pain differ from other skin senses?

Answer 32

When stimulus producing pain is removed, the sensation may continue (e.g., chronic pain)

Very cold toes - sense pain when toes are warming up to room temperature

Question 33

Gate-control theory of pain

Answer 33

The experience of pain depends in part on whether pain impulses get past a neurological “gate” in the spinal cord and reach the brain (2min 32sec mark).

Question 34

Neuromatrix theory of pain

Answer 34

• Matrix of neurons in the brain is capable of generating pain (& other sensations) in the absence of signals from sensory nerves.
• Accounts for phantom pain.
• 38 minute mark

Question 35

Kinethesis

Answer 35

Sense of body position and movement of body parts (also called kinesthesia).

Question 36

Equilibrium

Answer 36

Sense of balance.
- Influenced by semicircular canals: sense organs in the inner ear that contribute to equilibrium by responding to rotation of the head.

Question 37

Inborn abilities

Answer 37

Infants born with basic sensory abilities which rapidly develop.

Question 38

What other ways is perception influenced

Answer 38

Needs: more likely to perceive something when we need or have an interest in it.

Beliefs: What we believe and can affect what we perceive.

Emotions: can influence interpretations of sensory information (especially pain and fear)

Expectations: previous experiences influence what we perceive (e.g., perceptual set).

Question 39

How does perception differ through culture?

Answer 39

• Different cultures provide different environments and levels of practive.
• Muller-Lyer illusion not effective in “less-carpentered” cultures.
• Western cultures focus more on figure than ground; East Asian cultures focus more on context.