This post was contributed by Denise Breitenbach and Yvonne Whelan
Introduced by Prof. Mark Johnson, this year’s Birkbeck BabyLab Showcase highlighted the importance of researching aspects of infant cognition over time. Between birth and adolescence, our grey ‘jelly-like’ brains expand three times in size and undergo an astounding amount of structural adaptation. These changes aren’t solely reliant on our genes: genetic information unfolds over time by interacting with our external world experiences. For example, social skills related to the processing of facial cues such as smiling, develop early on as children experience seeing others’ faces. Early life contextual factors can also impact negatively upon development: poverty has been linked to effects on the brain which can result in a range of mental health difficulties.
So how are BabyLab scientists linking structural brain changes to the development of perceptual, cognitive, motor and language abilities? As babies often lurch rapidly between contented gurgling, gutsy wailing and gentle snoozing, novel experimental techniques are required. These include: 1) Behavioural testing such as eye tracking (e.g. used for testing preferential looking at faces versus complex objects) 2) Electromagnetic recording methods (EEG/ERPs) using a damp hat to record tiny voltage changes on the scalp as groups of neurons synchronously fire together on exposure to a task 3) Optical imaging (NIRS), where weak light beams are used to track blood flow in the brain as babies are thinking/perceiving stimuli 4) MRI scanning – used for sleeping babies to discover more about brain structure and functioning.
Changing their mind
In the first showcase talk, Dr Natasha Kirkham explained how good working memory (WM) and inhibitory control (IC) in children contribute to the development of decision-making, remembering of rules and the production of contextually appropriate behaviour (e.g. speaking loudly in assembly, but not at the cinema). Childhood development of WM and IC has been tested using the Dimensional Change Card Sort Task where firstly, children were asked to match a target card with reference stimuli according to shape, and then to only match according to colour. Although 3 year olds performed worse than 5 year olds where there was a category conflict according to the prior rule (e.g. a red truck had to be matched with a red star), scaffolding a 3 year old child’s learning experience helped to improve their performance. For instance, instructing them to repeat a new rule, rather than solely providing ‘yes/no’ feedback to card choices delivered the greatest improvement. Next, Natasha provided us with an additional experimental example testing WM and IC – the ‘Delay of Gratification Task’ where in order to earn many more Oreo cookies, children were asked to refrain from eating those already placed before them until an adult re-entered the room. Amusing strategies employed included children sitting on their hands or putting cookies in drawers!
Shining Light on the Infant Brain
In the second showcase talk Dr Sarah Lloyd-Fox informed us how an exciting and novel way to shine light on the functioning of an infant’s brain is to do it literally by using a technique called NIRS. This works by shining a weak light into the infant’s head which passes through the infant’s skull and reaches underlying brain tissue.
NIRS comes with many benefits to researchers: it can be used on babies who are awake (so they can be tested with visual imagery rather than sounds only) and has better spatial resolution than MRI. At Birkbeck, NIRS has been used to investigate when infants start to see and interpret actions, alongside questions such as ‘is our ability to use our hands to interact with our environment related to how we respond when we see other people performing similar actions?’. As emphasized by Dr. Natasha Kirkham earlier, the experimental value of play should never have been underestimated and this question was examined using games testing infants’ manual expertise. Intriguingly enough, evidence suggests that there may be a relationship between the way our developing brain responds to the sight of human motion and the motion we learn to form ourselves.
Infant time perception – ‘Escaping the Eternal Now’
In the third talk Dr Caspar Addyman highlighted how babies are often absorbed in something in the ‘now’: “in one moment babies can be in howls of tears and the next, in peals of laughter”.
How is it that humans gauge how quickly an event ‘feels’? Caspar described how for adults the longer ago something occurred, the fuzzier a memory exists of it. Judging the ‘fuzziness’ gives us a measure of how long ago in time it occurred. Since infants’ memories are not very well developed, it is difficult for them to judge the continuity of events. Thus, in order to learn more about the development of infants’ perception of time, BabyLab researchers are testing the long and short term memories of 6, 10 and 14 month olds using habituation (the classic technique of making babies bored!) with heart rate measures and eye movements being monitored. In addition, movement is thought to be very important to an infant’s developing understanding and judgement of time and events – at 6 months the world has to come to you, by 14 months exploration increases as crawling and walking ensue, expanding an infant’s sphere of the world. Such interaction may link to changes in the judgement of time. This is ongoing research and we look forward to hearing the results of Caspar’s study in the future.
Autism in infancy
The final talk, given by Dr Teodora Gliga, described the progress developmental science is making towards understanding autism spectrum disorders (ASD). ASD are presently diagnosed from 24 months onwards when children fail to meet social communicative developmental milestones. Researchers at Birkbeck are investigating how ASD can be detected and diagnosed earlier, for example by trying to decipher the pre-requisites for language development. As ASD is a genetic disorder (there is a 10% chance of developing ASD if one has a sibling with it vs a 1% chance for the general population), a prospective longitudinal study has been used to investigate infants who have siblings with autism over a 3 year clinical assessment period.
Evidence indicates that although there are no differences in paying attention to faces between ASD and typically developing infants at 6 months and 12 months, there are early differences with gaze direction and a failure to follow gaze from 6 months – a precursor of social ability. In order to inform intervention strategies, future studies will need to focus on testing children at multiple time points and using measures such as attention (looking away from irrelevant objects), the ability to discriminate gaze direction, follow gaze, to acquire words, maternal input (words child hears), the social and biological environment, a child’s genes, and risk factors during pregnancy.
Read more about BabyLab research in the news.
