crossmodal perception in infants

Question 1

when are basic blueprint of nervous system in place?

Answer 1

By 6mths of gestation most neurons have been produced

Question 2

how long does infant brain undergo rapid changes?

Answer 2

newborns brain continues to undergoes rapid changes during first 2 years of dev

Question 3

what are such changes associated with?

Answer 3

changes are associated with changes in strength of synapse and how neurons communicate with each other and those connections consolidate

Question 4

what is synaptic pruning?

Answer 4

Synaptic pruning refers to the process by which extra neurons and synaptic connections are eliminated in order to increase the efficiency of neuronal transmissions.

Question 5

what is synaptogenesis?

Answer 5

Synaptogenesis is the formation of synapses between neurons in the nervous system. Although it occurs throughout a healthy person’s lifespan, an explosion of synapse formation occurs during early brain development, known as exuberant synaptogenesis.

Question 6

process involved in synaptic pruning?

Answer 6

synaptic pruning, closing down of connections that are present at birth but are not used, overconnectivity patterns in newborn that gets shaped through experience, by keeping those connections that are functional through synaptogenesis and gets rid of them through pruning

Question 7

what is the importance of myelination?

Answer 7

myelination allows for more efficient communication of info from one neuron to another

Question 8

what did Piaget postulate?

Answer 8

how does a child understand the shape of an object that’s learned through vision, and is then transferred to the tactile division so child can learn to pick object up?
to see, to act on, to grasp are v inefficient at birth
he claimed that there are no automatic transfers of info across the senses, so observational learning occurs, which has to build up through learning associations through sight and tactile feedback once baby has grasped the object

Question 9

what did Piaget say that underpinned learning associated b/w diff systems?

Answer 9

aligned thinking with how the brain develops using synaptogenesis and pruning as the mechs that underpin the learning associated between diff systems, how associations are manifested in the brain

Question 10

Kennedy, Bullier and DeHay, 1989? Sensory differentiation from birth

Answer 10

ewborn animal found that there are connections between visual and auditory system and without relevant experience, but those connections get pruned away

Question 11

Sur and Leamey, 2001(!)?

Answer 11

The immature cortex is not specialised, and specialisation is experience dependent and depends on the input to develop it. if you disconnect ear from thalamus then you get the visual system innervating all regions of the auditory cortex, brain changes depending on the nature of the input received
reminiscent of congenitally deaf and blind people, brain is specialised in a diff way. vis system is recruited by other sensory systems, reconfiguration according to nature of input.

Question 12

Atkinson, Braddick, 2003? cortex is not quite mature at birth

Answer 12

The cortex of the human newborn is barely functioning: it is anatomically immature, low blood flow and failure of behavioural markers like trying to figure out which cortex is responsible for which behaviour.
…subcortical structure such as limbic system are mature at birth, however!

Question 13

Wolff, 1974? transient connections at birth, why?

Answer 13

tactile stim of wrist evokes a response in somatosensory region, only in newborns is the response enhanced when accompanied by white noise! all freqs are presented in white noise.
transient connections might actually be increasing the activation of somatosensory cortex from other cortical systems

Question 14

Neville, 1995?

Answer 14

large REP response over temporal regions activated by speech, only in infant brain is the visual cortex also activated by spoken language! this activation prunes overtime.

Activation declines to adult levels by three months :(

Question 15

Murray and Mishkin, 1985? crossmodal associations in newborn mediated by limbic system

Answer 15

crossmodal associations in newborn mediated by limbic system:
lesions of monkey amygdala abolished crossmodal matching between vision and touch

Question 16

Nunn, 2002? synaesthetes

Answer 16

spoken words also elicits activity in V1 of synaesthetes

Question 17

what is synaesthesia?

Answer 17

synaesthesia is a condition that senses are described as merging, stimulation of one sensory modality leads to realistic, vivid sensation in one or more senses, ”union of the senses”.
Hypothetically, any sensory combination is possible

Question 18

what is grapheme colour synaesthesia?

Answer 18

most synaesthetes see colours to letters, grapheme colour synaesthesia will see colour red when they see the colour A. they perceive a colour in association with perception of that letter.

Question 19

how do synaesthetes describe the experience?

Answer 19

They describe their experience as occurring in mind’s eye or projected out to env.

Question 20

does synaesthesia change overtime?

Answer 20

synaesthesia does not change overtime and is v inheritable, tells us something about nature in which our brains are wired, wired up to expect multi sensory inputs, synaesthesia acts as a model to underpin genetics and brain wiring and links in with conscious awareness of our world.

Question 21

what type of condition is synaesthesia?

Answer 21

it IS NOT A PSYCHIATRIC, MEDICAL OR CLINICAL CONDITION!!! do not say this in essays, reports say that synaesthesia is enhanced perception, memory and creativity! Synaesthetes have unique perceptual qualities.

Question 22

relation between early exposure to fridge magnets in synaesthetes?

Answer 22

coloured letters fridge magnets as child, synaesthetes having them when young and chances are higher that the colours they see with letters are the colours they had on magnets on their fridge…

Question 23

is the neural process of pruning lessening the effects of synaesthesia?

Answer 23

what do transient connections lead to what type of perceptual experiences? synaesthesia is associated with a lack of pruning that are common to all of us at birth! Therefore, are newborns synaesthetic, and does the process of neural pruning ‘lessen’ such perceptual quality?

Question 24

is cortex is undifferentiated at birth?

Answer 24

cortex is undifferentiated at birth so connections that do occur are mediated by subcortical systems, lower than the cortex.

Question 25

what did Daphne Maurer pose?

Answer 25

DAPHNE MAURER, she posed that are all newborns synaesthetic? are we all born as syn’s? and is then pruned away but for some these connections are maintained..at 4 months the senses become modularised because of experience, overconnectivity in newborn is inefficient as it is not modularised. “feelings have taste”, “sights have sounds” etc.

Question 26

what did Maurer and Mondloch, 2005, later state?

Answer 26

they later stated the hallmark is that arises from the perception of single stimulus, gives rise to true percept of that stimulus but also a secondary perceptual experience, opposite of which fuses info across diff senses into a combined percept. idea that synaesthesia is associated with two percepts which are present at the same time, in 2005 paper that cross modal associations are being formed with transient connections.

Question 27

Marks, 1987? AIB ad haha

Answer 27

Easier to match higher pitched tones with small bright lights, some ppl likened that to a type of synaesthesia. nice ad from a perc point of view! AIB see lights turning on in houses in line with the music, if music is increasing its tone so are the lights! if pitch was going down we would find that diff to process if the tone was increasing.

Question 28

what is the concept of U shaped development?

Answer 28

left with idea that brain is overconnected at birth and gets pruned away, cortex becomes specialised and see greater efficiency in domain areas with specialisation. U shaped development across cross-modal perception, because of emergence of specialisation in brain…damn! 6mth on see evidence for gradual emergence of associations between diff modalities, beginning of U shape is associated with innate structure of brain at birth, then ability declines because of perceptual narrowing, then infant acquires ability to associate a diff face with particular voice with identity of person for example emerge at 6mths.

Question 29

Pickens, 1994? U shaped dev

Answer 29

5-6mths show no prefs for voice matching or mismatching and look equally. younger infants do show pref for the same things! somewhere between 5-6mths old the bottom of the U is showing itself.

Question 30

Steri and Pecheux, 1986? U shaped dev

Answer 30

4-5mths fail to discriminate object through touch until they become habituated, show them a visual version of thing they can’t discriminate. younger babies can do this tho! they learned to dishabituate. why is this in our evolutionary history?

Question 31

Lewkowicz and Turkewitz, 1980? (piaget, associations need to be learned across the sensory systems)

Answer 31

1mth olds habituate to patch of light transfers to a sound of same intensity. if light is bright they habituate to a bright light that is transferred to sound, shows that there’s no breakdown in their ability to perceive.

Question 32

Steri, 1987? crossmodal links between tactile and vis stim

Answer 32

2-3mths show tactile habituation to shapes in mouth, which transfers to visual shapes, showed ability to transfer info across diff sensory systems. 6-pointed star pacifier, and infant continued to habituate to similar visual stimulus. v young infants have these cross modal links from birth which declines as they get older.

Question 33

what did George Berkeley believe?

Answer 33

GEORGE BERKELEY believed that cross modal associations are learned and are not innate, need experience to understand that two things belong together from different senses.

Question 34

what did Gibson believe?

Answer 34

GIBSON believed that crossmodal transfers are innate.

Question 35

how did MELTZOFF, 1979, question their beliefs?

Answer 35

can human babies understand what they’re feeling is the same as what they’re seeing. gave pacifier to suck that they didn’t see until afterwards. tactile familiarisation stage and then tested with visual stimuli, neonates looked longer at visual stim that they were previously exposed to through touch!! could discriminate the info from diff sensory domains, argued that this CANNOT have been learned as there’s no visual stim in utero, evidence for innate ability to transfer info from touch to vision.

Question 36

how did Daphne Maurer test Meltzoff's idea?

Answer 36

MAURER tested this idea again and study was more controlled, control for bias that babies show spontaneous preference for one side of visual field over another and prefer to look at one side of visual field spontaneously. have a bias for certain stimuli over another, might prefer stimuli with things on it or smooth, when you rule those out you have a good controlled design to test idea that kids can transfer info from one modality or another. MAURER argued that new born babies do not have ability to transfer info from one modality to the next, and failed to replicate the findings.

Question 37

Meltzoff and Moore, 1977? imitation

Answer 37

newborn babies can imitate using facial actions which involves a knowledge of tactile and proprioceptive info to mimic what they’re seeing, evidence for cross modal transfer between what baby is looking and what they can produce from diff sensory systems to mimic parents facial expressions. no visual expression presented in utero. this study is not evidence, could be spontaneous gestures that babies make and non-specific and hard to make judgements about whether they were intentional imitation. However this cannot be learned as there is no vision in utero. first test you do when your baby is born!!!! hahaha

Question 38

STERI’S lab in france 2007? bidirectional transfer of info

Answer 38

what extent do babies transfer info from vision and touch and back again in touch and vision, cross modal shape transfer is not bidirectional at birth, object was presented visually they didn’t transfer that info when they felt the object. shape info doesn’t transfer bidirectionally but texture does :0 ...can visually recognise object previously felt, but cannot recognise an already seen object by touching it. tactile to vis object transfer might be related to hand dominance and the rate at which info is transferred.

Question 39

LeJeune, 2010? holding time

Answer 39

successive presentations of object results in a decrease in holding time in babies born preterm, holding time increases with novel objects. senses are geared to receive these types of info we are likely to be presented with when were born. vision to touch improves but touch to vision does not improve, vision to tactile shape perc is much better than the other way around.

Question 40

Picard, 2007? vision to touch texture matching

Answer 40

vision to touch texture matching performance improved with age from 5-8years. Tactile to visual performance however did not improve (same as touch to touch performance)

Question 41

Ghazanfar and Legothetis, 2003: audio-visual interactions/crossmodal

Answer 41

monkeys showed preference for looking at the video which matches the vocalisation than non-matching video. Monkey’s ability to match across modalities may be an evolutionary precursor of humans’ ability to make the crossmodal associations necessary for speech perception.