Although executive functions in childhood: development and disorder is probably one of the more complex chapters, the notes on it are amongst the shortest. Executive function refers to those activities that are under conscious control rather than being habitual or automatic functions that we do. Things tend to move from executive function activities to automated ones over time eg when you started to read it was very much an executive function but everyone reading this will be doing it pretty much automatically. This activity is handles by the prefrontal cortex. It’s generally divided into cognitive flexibility, planning and working memory and inhibitory control. Hughes et al looked at this using the Tower of London task which revealed good correlation between poor scores on the task and poor communication skills and high anti-social behaviour.
The development of executive function in children has been looked at by a number of researchers. The Stroop task (colours and colour names mixed up eg RED). Diamond discovered some inhibitory control at 9 months and improvement at 10 months. Piaget’s A-not-B and the go/nogo (press a button when a letter that’s not “X” appears) are also used. There are variants of this for children who can’t read eg the fist and pointing hand however they are more complex and it takes a 4 year old to pass them. Casey et al looked at these using fMRI scans which showed that children, as you would expect, needed more brain power dedicated to them than adults do. Finally, there’s the Wisconsin Card Sorting Test with different shapes and colours.
Executive disfunction is a massive field of study throwing up peculiar effects. Children with poor inhibitory control tend to be more distractible, less able to control emotions, more impulsive, etc. and have difficulty in social situations and tasks needing concentration. ADHD involves distractibility, impulsivity and hyperactivity; they have delayed myelination of the prefrontal cortex and low levels of dopamine. Since it’s hard to pick this up before age 6, Parker & Asher looked at pre-schoolers who are classed as disruptive and found that basically it was downhill from there.
Overall, a surprisingly short set of notes for what’s quite a massive field but presumably we’ll be picking this up in somewhat more detail at level 3. I can’t believe that the next installment on understanding minds is the last one to be done!
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