Lecture 5 - Mental imagery

Question 1

What is mental imagery?

Answer 1

Internal representation that creates the experience of sense-perception in the absence of appropriate sensory input

Question 2

What does pictorial mean?

Answer 2

• imagery is pictorial
• what is imagined is recreated in the mind as a picture

Question 3

Functional equivalence - Kosslyn & Decety?

Answer 3

• Imagery is generated using neural machinery used for sensation and motor control
• Visual imagery relies on visual system
• Motor imagery relies on motor system
• Much processing associated with visual imagery occurs in the visual cortex
• Believes visual imagery closely resembles visual perception

Question 4

Propositional codes - Pylyshyn?

Answer 4

• Argued visual imagery differs substantially from visual perception
  -> Imagery is an epiphenomenal product of propositional code
  -> Images are manipulated by manipulating symbolic representations, not the image itself (e.g. changing the code in a computer program)
  -> Imagery is independent of sensory and motor systems
  -> Performance on mental imagery tasks does not involve depictive or pictorial representations, instead it involves tacit knowledge

Question 5

Behavioural evidence?

Answer 5

• Mental rotation (Shepherd & Metzler 1971)
  -> Decide if two figure are same or different
  -> Reaction time increases linearly with angle
• Mental scanning ( Kosslyn, Ball & Reiser 1978)
  -> Memorise a map, then imagine the map
  -> P’s asked to focus on a specific point on the map
  -> Asked to scan and report if a feature was present or absent

Question 6

Cognitive neuroscience evidence?

Answer 6

• imagery activates visual areas involved in perception
• activation depends on the task
  -> high resolution imagery tends to activate early visual areas
  -> spatial judgements tend to activate more dorsal visual areas
  -> non spatial judgements don’t require high-res comparisons
• TMS over V1 disrupts visual imagery
• Meta-analysis of brain imaging data suggests Left Fusiform Gyrus is the critical node for imagery not V1
  -> Left FG is part of ventral visual pathway for object recognition

Question 7

Neuropsychological evidence?

Answer 7

• MS (an achromatopsic patient) can’t imagine colours
• Some patients with left-neglect & hemianopia (blindness on one side) can’t generate images
• Making eye-movements reduces intensity of visual imagery

Question 8

What is tacit knowledge?

Answer 8

knowledge that is unconscious or that cannot be articulated

Question 9

Individual differences?

Answer 9

• mental imagery ability varies across individuals
• some neurotypical people are ‘aphantasic’ = unable to create mental images
• mental imagery declines with age

Question 10

Functions of mental imagery - Paivio?

Answer 10

• said imagery has 2 functions with 2 levels
• distinguishes between imagery content and imagery function
• there is:
  1. cognitive specific imagery
  2. cognitive general imagery
  3. motivational specific imagery
  4. motivational general imagery

Question 11

Cognitive specific imagery?

Answer 11

• imagery can be used to modulate behaviour
• Driskell, Copper & Moran (1994)
  -> meta analysis of cognitive specific imagery to enhance skill
  -> imagery effective, but not as effective as real practice
  -> experts benefit more from mental practice than beginners
  -> effects of mental practice fade over time
• there is not an optimum amount of mental practice - the more the better

Question 12

Cognitive general imagery?

Answer 12

• athletes use general imagery

Question 13

Motivational specific imagery?

Answer 13

• e.g. imagining winning or being praised for good performance
• imagery is important for goal setting

Question 14

Motivational general imagery?

Answer 14

• imagery can increase arousal and can be used to increase/ control it
• imagery is used for limiting the effects of anxiety
• Badminton players report increased confidence after using imagery (Callow, Hardy & Hall, 2001)