Core Studies: Casey

• What does it study?

  Contemporary study of delayed gratification.
• Background part 1?

  1. Mischel examined delayed gratification- the ability to resist immediate reward to gain greater reward later.
  2. Mischel did Marshmallow test with 4 year olds, given marshmallow, told could wait and resist temptation to eat, would receive second marshmallow later
• Background part 2?

  3. Mischel found one third children who resisted initial marshmallow used cooling strategies redirect attention eg pretend it was a fluffy cloud

  4. Casey expand on this, assess adults with more complex task (go/nogo), to link delayed grat in childhood to impulse control in adulthood to see which brain regions active in high and low delayers
• Sample

  High and low delayers, men and women from Mischel's marshmallow test sample from Stanford Uni nursery school in 60s/70s, 59 in Exp 1, 26 in Exp 2.
• what was sampling method, adv and dis

  opportunity sample and longitudinal research, adv: insight whether delayed gratification is stable trait, dis: risk of participant attrition
• What was Casey's aim?

  1. assess whether delayed gratification in childhood predicts impulse control activities when participants were older (adults)
  2. investigate sensitivity to alluring social cues
  3. investigate impulse control on a behavioural and neural level
• What materials were used

  Exp 1: NimStim set of faces which had various expressions neutral, happy or fearful

  Exp 2: fMRI scanner for brain activity, E-prime software to display , responses on Neuroscope 5 button response pad
• What were the conclusions?

  1. sensitivity to environmental hot cues (more alluring social cues) plays a significant role in an individual's ability to supress actions towards alluring cues
  2. resistance to temptation is a relatively stable individual trait- shown through brain activity; in low delayers inferior frontal gyrus has less activation and ventral striatum is more active
  3. individuals at age 4 who have difficulties delaying gratification have difficulty as adults in terms of suppressing responses to positive social cues
• What was the procedure of the behavioural experiment 1?


  Ps completed go/nogo task with hot and cool versions to test their ability to delay gratification. Cool task- told to press one gender 'go' and not press for other gender, all had neutral expressions. Hot task- shown happy faces or shown fearful faces, targets alternated (which go and which nogo). Ps instructed to respond as quickly and as accurately as possible, face only appeared for 500 milliseconds with 1 second intervals between faces. There were total of 160 trials per run in a pseudorandomised order.
• What was Casey's procedure in the physiological experiment 2?


  As no significant differences found in cool task of experiment 1, ps only did hot version of go/nogo task in fMRI scanner. Stimuli and instructions same as exp 1 but were differences in timing and number of trials.
• What were the results from experiment 1? (all quan data)


  1. no significant differences found in high and low delayers in terms of reaction time (over 99% accuracy for both tasks on go trials)
  2. significantly higher mean false alarm rate in nogo trials for low delayers- cool task (gender) 9.96% and hot task (expressions) 12.2%
  3. low delayers performed worse on hot task, particularly happy faces had more false alarms
• What were the results of experiment 2?


  1. accuracy rates consistently high for hot task for high and low delayers (average 98.2%)
  2. performance more mixed on nogo trials than go trials (overall average 12.4% false alarm rate)
  3. low ds had more false alarms (14.5%) than high ds (10.9%) BUT difference was not statistically significant
  4. imaging results showed low delayers had reduced levels of activity in their right inferior frontal gyrus which controls impulses when giving correct 'nogo' responses, low delayers significantly more activity in ventral striatum (associated with rewards)
• What were the conclusions from experiment 1?


  1. low delayers at age 4 have more difficulty suppressing responses to happy stimuli
  2. context affects how easy it is to delay gratification
• What were the conclusions from experiment 2?


  1. frontal region of brain active (although less active in low delayers) when resisting temptation
  2. ventral striatum exaggerated activity in low delayers- more alluring social cues harder to resist
  3. different regions of the brain have more activity for cool and hot system