Multisensory integration - cue combination

Question 1

Testing conflicts between vision and touch

Answer 1

• create artificial conflicts between senses
• look through a reducing lens and determine size of object
• vision dominates as we trust it more
• touch has small but consistent influence

Question 2

Is there a strict sensory hierarchy?

Answer 2

no. audition can dominate vision when reporting number of visual flashes, number of auditory beeps determines reported number of flashes

Question 3

Modality precision hypothesis

Answer 3

modality with the highest precision (lowest uncertainty) chosen depending on task:

• spatial task–>vision
• temporal task–>audition

Question 4

Sensory uncertainty due to

Answer 4

• perceptual limits e.g. spacing of photoreceptors in fovea
• neural noise e.g. synaptic noise
• cognitive resource limits e.g. attention

Question 5

What does haptic input mean?

Answer 5

sense of touch

Question 6

what does visual capture mean?

Answer 6

the dominance of vision over other senses

Question 7

how can we create sensory conflict between visual and haptic feedback?

Answer 7

• the bar is virtual, height of it changes
• robot phantom finger device glued to finger
• illusion of seeing and feeling a bar

Question 8

normative model

Answer 8

• how the problem should be solved

- based on theory

Question 9

process model

Answer 9

• how the problem is actually solved

- based on data

Question 10

how do we solve the problem of sensory integration?

Answer 10

-pick an integration method that minimises sensory uncertainty –> maximum likelihood estimation method

Question 11

what does high variance mean?

Answer 11

high sensory uncertainty and lower probability

Question 12

how do we solve sensory conflicts between estimates of probability?

Answer 12

combine estimates of both

Question 13

do we always integrate information optimally?

Answer 13

need to know uncertainty of diff senses for optimal integration
-can be hard to estimate
-easier in sensory perception than cog reasoning
calculations can be intractable/take long time
-heuristics are suboptimal but fast
-good enough solutions often satisfactory

Question 14

are probabilities encoded in the brain?

Answer 14

• there is little direct electrophysical evidence but there are several plausible schemes proposed
• uncertainty needs to be represented in some way

Question 15

correspondence problem

Answer 15

-is it 1 dog or 2? can see one and hear the other