Casey

• Background Q: introduce Walter Mischel's concept of delayed gratification

  Casey was inspired by Walter Mischel's concept of delayed gratification which can be defined as the ability to resist temptation and hold off for greater reward later
• Background Q: the marshmallow test

  To research this Mischel designed the 'marshmallow test' in which 562 children (4 years old) from Stanford Bing nursery were given a marshmallow and 2 choices: either to eat it immediately or wait 15 minutes and get a second one.
• Background Q: what did he find in relation to high delayers

  He found that 1/3 of the children were able to resist temptation as they practiced cooling techniques e.g. looking away/closing their eyes. He defined them as high delayers.
• Background Q: Casey's inspiration - use of adults, more complex task + interest in the brain

  Casey wanted to investigate impulse control in adults by using a go/nogo task to see if there were differences in brain activity in certain regions in high and low delayers e.g the ventral striatum and the inferior frontal gyrus.
• The inferior frontal gyrus of the brain

  involved in resolving conflict between 2 competing actions like the cognitive control/strategies we use when resisting a reward. its also linked to out interpretation of facial expressions + our corresponding emotional response. there is also a relationship between avoidance of risky behaviour and increased activity in the inferior frontal gyrus.

  high levels of activity in the inferior frontal gyrus = high delayer
• The ventral striatum (in the limbic system)

  most closely associated with reward processing, it helps us balance and facilitate our level of motivation and is active during the anticipation + receipt of monetary + social rewards
• More on the background

  alluring situations diminish our ability to control our impulses, alluring situations changes with age

  tasks w cognitive controls = more difficult for adults: go (press a button)/nogo task (refrain from pressing the button)

  Casey wanted to conduct a follow up study, to see if children in og experiment who were able to delay gratification were able to do this consistently in life, also wanted to see if there were any physiological differences in brains of her Ps which may be able to explain the link with delayed gratification
• Casey's main aim

  to build on previous research to assess whether delay of gratification in childhood predicts impulse control activities in adulthood/when Ps are older -> study was looking at impulse control on both a behavioural level (go/nogo task - if they pressed the button) + on a neural level (which regions of the brain are active - using fMRI scans)
• Secondary aim

  To investigate sensitivity to alluring or social cues (happy faces) - its difficult for adults to resist responding to a happy face
• Research method

  Quasi experiment

  IV = whether P is a high or low delayer (naturally occurring)

  DV = performance on the impulse control task (go/nogo task) in terms of accuracy and reaction time, plus activity in regions of the brain (from the fMRI) in experiment 2
• What was the experimental design

  as some Ps completed self control scales when in their 20s + 30s + those Ps in experiment 1 did both the "hot" and "cool" go/nogo tasks means the study had a repeated measures design in some parts
• What type of study was it

  longitudinal study which followed some of the original Ps from the age of 4 years until they were in their 40s

  + can track the development of delayed gratification from childhood into adulthood

  -participant attrition (high dropout rate) -> experiment 1 = 59 Ps, experiment 2 = 27 Ps
• Study detail

  Ps were already tested once when they were 4, once in their 20s and once in their 30s -> found impulse control was consistent across all 3
• Sample (of experiment 1)

  • Ps were taken from the original delay of gratification experiments conducted in the 1960s/70s
  • 59 Ps agreed to participate with 32 high delayers + 27 low delayers (based on previous findings)
  • 36 women, 23 men:

  -high delayers = 20 women, 12 men, mean age 45years

  -low delayers = 16 women, 11 men, mean age 44 years
• What did experiment 1 measure

  impulse control on a behavioural level - how quickly/accurately Ps press the button for 'go'
• Experiment 1: material + stimuli

  material = faces were selected from the NimStim set of faces

  the researchers developed 2 tasks to examine impulse control: one with 'cool' stimuli + one with 'hot' stimuli. the social cues of faces were used, with various emotional expressions.
• Procedure for experiment 1: hot + cool version

  Ps were asked to perform a go/nogo task (which tests the ability to delay gratification). they consented to take part in this behavioural version of an impulse control task.

  COOL VERSION: Ps were told to press the button for one gender ('go') and not press the button for the opposite gender ('no-go'). the facial expressions of the people in the images were neutral

  HOT VERSION: Ps were shown happy or fearful faces. these targets were alternated e.g. sometimes happy is go + sometimes happy is nogo
• Procedure for experiment 1

  • Ps were instructed to respond as quickly as possible + as accurately as possible
  • a face appeared for 500 milliseconds followed by a 1 second interval
  • a total of 160 trials were presented per run in pseudo randomised order (generated by a computer in a random order)
  • accuracy of responses was collected: the hit rate of go responses (correctly pressing) + the suppression rate for nogo (correctly not pressing)
• Results for experiment 1
• Sample for experiment 2

  • only 27 Ps from experiment 1 took part in experiment 2
  • one participant was excluded for excessively poor performance of the fMRI task so data comes from 26 Ps
• Materials/apparatus in experiment 2

  • Object E-Prime software was used to display the task onto a projection screen
  • Ps responses + reaction were recorded on a Neuroscan 5 button response pad
  • Ps were scanned in a fMRI scanner which measures brain activity + function by detecting changes associated with blood flow
• Procedure for experiment 2

  • while in the fMRI scanner Ps only completed the 'hot' version of the go/nogo task
  • the stimuli + instructions were identical to those used in experiment 1 however there were differences in the timing + number of trials
  • there were 2 runs, one with a happy face + one with a fearful face
• Experiment 2 results pt1

  
• Experiment 2 results pt2

  
• Example Q: Explain how Casey's study could be described as a longitudinal study

  • tracks development of behaviour overtime (tracks development of delay of gratification to see if delay of gratification in childhood can predict impulse control in adulthood by measuring impulse control of adults in 40s who'd had their impulse control measured @ 4 yrs, in their 20s + in their 30s)
  • studies the same individuals over a long period of time (Ps were measured more than once over a period of around 40 years as Casey used 59 Ps in their 40s who took part in Walter Mischel's marshmallow test into delay of gratification at 4 years old)
• Example Q: Give one strength and one weakness of this method (longitudinal study)

  
• Conclusions

  
• Example Q: Outline one conclusion from Casey's study

  One finding from Casey's study was that low delayers perfomed worse on the hot task particularly when happy faces were the 'nogo' stimuli. This allows Casey to conclude that the more alluring a social cue, the more difficult it is to resist the temptation of that stimuli.
• Link to biological approach question

  
• Link to key theme question

  
• Evaluation table

  
• What debates does Casey link to

  • reductionism = reduces delay of gratification to biological factors such as brain activity in the ventral striatum + inferior frontal gyrus, ignoring situational/environmental factors
  • nature = explains delay of gratification + impulse control using the biological factors of activity in the ventral striatum + inferior frontal gyrus
• E1 results