Mental imagery

Question 1

Kosslyn et al. (1995) definition of visual mental imagery

Answer 1

‘Seeing’ in the absence of the appropriate immediate sensory input.

Question 2

4 component processes of mental imagery.

Answer 2

1. Image generation.
2. Image transformation.
3. Image inspection.
4. Image retention.

Question 3

3 ways to manipulate mental images.

Answer 3

1. Mental rotation.
2. Image scanning.
3. Reinterpreting ambiguous images.

Question 4

5 approaches to the study of mental imagery.

Answer 4

1. Introspection (Sir Francis Galton).
2. Behavioural (chronometric studies of image transformation).
   3) Comparative studies (do pigeons mentally rotate?).
   4) Neuroimaging (neural structures activated during imagery).
   5) Neuropsychology (imagery deficits following brain damage).

Question 5

What did Galton (1880) find?

Answer 5

Some people are aphantasic (the inability to form mental images of objects that are not present).

Question 6

Shepard and Metzler (1971) setup

Answer 6

Mental rotation experiment: 2 shapes presented at various orientations (either the same or mirror images. Participants had to judge same-different as quickly as possible.

Question 7

Shepard and Metzler (1971) results

Answer 7

A linear relationship between angle of rotation and mean reaction time (for both picture plane pairs and depth pairs).

The limit on mental transformation seems to be 60°/sec.

Question 8

Cooper (1975) mental rotation

Answer 8

Used a variety of complex shapes and replicated the results of Shepard and Metzler (linear relationship).

The complexity of the stimulus does not affect the speed of rotation.

Question 9

Kubovy’s (1983) objection to ‘mentally rotate’

Answer 9

The rotation is being imagined - there is not actually something spinning in people’s head.

Question 10

Rock et al.’s (1989) explanation of the relationship between RTs and mental rotation angle.

Answer 10

Alternative to ‘mental rotation’: the relationship is just a consequence of the difficulty of comparing rearranged features (assigning principle axes).

Question 11

Rock et al.’s (1989) study to support principle axes.

Answer 11

3D pipecleaner shapes are impossible to rotate. Asked people to imagine what they would look like rotated 90° to the left.

Argued that this is because it is difficult to determine what is ‘front’ or ‘right’ or ‘back’ (difficult to assign principle axes) so cannot imagine rotation.

Question 12

Cooper (1976) probing mental rotation setup

Answer 12

1. Assessed the speed of mental rotation.
2. Presented a 2D shape and instructed participant to rotate it.
3. Presented a probe comparison shape and participant had to make same/mirror-image judgements.

Question 13

Cooper (1976) probing mental rotation results

Answer 13

They found a flat slope (same reaction time for all angles) if the probe matched the expected rotation of the image.

But there is a linear increase between angular departure from expected orientation and RT. Suggests dynamic, continuous, analogue mental rotation.

Question 14

Richter et al. (1997)

Answer 14

Brain activation increases during mental rotation?

Question 15

Dennett (1991) the philosopher

Answer 15

A 3D shape made with cubes with a hole and a red surface.

Told people to create a mental image and asked whether the red surface would be visible to someone looking through the square hole in the wall.

The moment people tried to peer through the hole, the mental image falls apart. Argued that it is because looking through the hole is like looking down the principle axis so it is hard to determine where the other axes are.

Question 16

Hinton’s cube

Answer 16

Told people to spin the cube on one of its vertices and point to where the remaining corners are.

People point to 4 corners rather than 6 corners. (because rotation does something?). Cube has 2 principle axes and people could not keep track of the axes.

Question 17

Thatcher illusion

Answer 17

People don’t notice that there is something wrong with Thatcher’s face when it is upside down. Mental rotation is not objective - we don’t see what is actually there.

Question 18

Parsons (1987) rotating hands

Answer 18

RT is slower when imagining a hand rotate in a way that is physically difficult (people find it difficult to perform mental rotation for
physically difficult transformations).

Potential involvement of the motor system in mental imagery?

Question 19

Parsons (1995) neuroimaging of hand rotations

Answer 19

Asked participants to discriminated whether the rotated hand is a left or right hand.

SMA and premotor cortex recruited during mental rotation - motor areas are recruited during mental imagery (a seemingly only visual activity).

Question 20

Motor imagery (feeling like you are rotating it) in visual mental rotation

Answer 20

1. Motor cortex activity from neuroimaging.
2. Verbal reports from subjects in mental rotation studies (Shepard and Metzler).
3. Damage to motor areas can affect mental rotation ability.

Question 21

Wohlschlaeger (2000) ambiguous rotation

Answer 21

Ambiguous motion of a circle of dots. Flipping a hand clockwise or anticlockwise seems to control the direction of motion perceived.

Question 22

Why might visual imagery be constrained by the laws of physics?

Answer 22

Visual imagery involves motor imagery, which uses the same neural substrate required for actual movement.

Since physical movements are constrained by laws of physics, so are transformations of visual images.

Question 23

Hollard and Delius (1982) pigeon rotation

Answer 23

Shepard and Metzler-like task in which pigeons have to peck at the matching image.

Pigeons’ performance is a flat line (no mental rotation effects).

Question 24

Explanations of lack of pigeon rotation

Answer 24

Pigeons can fly and see the world from all angles, so they can discriminate the objects better?

Pigeons don’t have an advanced visual system so they treat mirror images as separate objects?

Pigeons have no hands?

Question 25

Wohschlaeger and Wohschlaeger (1998) mental and manual rotation

Answer 25

Mental and physical rotation shared an underlying process. When people mentally rotated an object while also moving their hand, performance was facilitated if hand and mental rotations matched and disrupted if they conflicted.

Question 26

Perky (1910)

Answer 26

Participants were told to imagine a given object (eg. banana) on a dark screen in front of them. They did not know that a faint picture of the object was projected onto the screen. Participants did not notice the picture (even though it was clearly visible in non-imagery conditions). The reported images had the properties of the projected picture (eg. the 'imagined' banana on its end). People confuse imagery and perception.

Question 27

Anosagnosic patient (Redlich and Bonvicini, 1907)

Answer 27

Patient had a lack of awareness that he is blind. He confuses mental images with perception - when he feels the warmness of a match he believes to see it.

Question 28

Merabet et al. (2004) consequence of prolonged blindfolding

Answer 28

Being blindfolded for a week led to visual hallucinations (occurred spontaneously, unlike mental imagery).

Question 29

Nair and Brang (2019) inducing synaesthesia in non-synaesthetes.

Answer 29

People claimed to see things when blindfolded after hearing an auditory inducer. Short-term visual deprivation facilitated auditory-evoked visual percepts.

Question 30

Farah (1988) 3 alternative explanations of mental rotation data

Answer 30

1. Tacit knowledge (we know how long images take to rotate and we use that knowledge to answer experimenter questions). 2. Experimenter expectancy (experimenters with different expectations found significantly different results). 3. Non-visual, spatial representations (congenitally blind patients also showed a mental rotation slope. MR functions are by spatial representations, not visual?)

Question 31

Fink and Kurtzman (1981) wagon wheel with central grating [try and reproduce stimulus and results function].

Answer 31

Participants were told to move their eyes along each spoke spokes of the wagon wheel and mark the point where they can no longer discriminate horizontal vs. vertical gratings in their peripheral vision. Tested this for both perception and imagery (memory). The functions for perception and imagery were nearly identical. The shape of the function reflected how we have better peripheral acuity than elevation, and better acuity of the ground rather than the sky. This suggests that imagery data is not a mere reflection of tacit knowledge. Those who just imagine doing the study would answer that they expect a perfect study.

Question 32

Ishai and Sagi (1995) mask and target distance

Answer 32

Participants either saw distractor gratings or were told to imagine distractor gratings. Target gratings are more perceptible in the presence of distractors. Perceived and imagined distractor gratings improve target detection similarly (although with perception, when the target-to-mask distance is too small, threshold elevation is greatly increased. This is not seem with imagery, potentially because participants just stopped imagining the distractors).

Question 33

Necker cube perception vs. imagery

Answer 33

The perceived cube flipflops between 2 interpretations but the imagined cue has just one interpretation.

Question 34

3 hypotheses about the cerebral organisation of visual imagery

Answer 34

1. Cortical areas for imagery and perception are anatomically separate. 2. Areas for imagery are a subset of those subserving perception. 3. Identical.

Question 35

Bisiach and Luzzatti (1978)

Answer 35

Neglect caused an imagery deficit as well as a perception deficit.

Question 36

Coslett (1997) double dissociation

Answer 36

2 patients with right hemisphere lesions. Double dissociation between visual imagery and visual perception tasks (given the same tasks).

Question 37

Cohen et al. (1996) fMRI MT during mental rotation

Answer 37

Increased activity in motion areas during mental rotation task of static image (are 2 imagines the same?) compared to control condition (comparison whether 2 images looked the same).

Question 38

Kosslyn et al. (1995) line drawings and area V1

Answer 38

Participants imagined objects on papers of different sizes (different size of mental image). Brain activity reflects V1's retinotopic organisation (larger mental image = activated more peripheral parts of V1). Imagining an object mimicked real vision in terms of which areas of V1 were activated.

Question 39

Kosslyn et al. (1999) TMS in imagery

Answer 39

Demonstrated that activation in V1 was not epiphenomenal but also functionally involved (doing the work). Participants were shown a quadrant, each with a different stimulus, and were told to imagine it. They were then asked questions that required them to compare 2 quadrants. Participants were significantly slower to respond when TMS temporarily lesioned V1 (compared to sham). Is V1 activation functional in mental imagery? Performance was not completely knocked out, suggesting the V1 is not necessary for imagery (just involved)?

Question 40

Howard et al. (1998) colour imagery vs. colour perception

Answer 40

Participants were asked colour or non-colour questions. Colour perception activated area V4 (colour area), but colour imagery did not.

Question 41

Dijkstra et al. (2017) bottom-up vs. top-down connectivity

Answer 41

Connectivity analysis showed that imagery involved more top-down connectivity and perception involved more bottom-up connectivity. Similar areas involved (top to bottom): inferior frontal gyrus, IPS, fusiform gyrus, OCC.

Question 42

2 mental imagery debates

Answer 42

1. Analogue vs. propositional. 2. Imagery vs. perception neural structures.

Question 43

Kreiman et al. (2000) face/non-face judgements with epilepsy patients

Answer 43

Even at the cellular level, imagery and perception appear similar. Neurons in entorhinal cortex fired selectively for during both vision and imagery (88% had identical selectivity - eg. face preference). Similar firing rates, but a bit weaker for imagery.