Casey et Al study (biological psychology)

• Name of the study?

  -“Behavioural and neural correlates of delay gratification 40 years later”
• What was the first aim of the study?

  • to see whether the same individuals who resisted at pre-school, could resit in adulthood
• What was the second aim of the study?

  • to see wether those classed as ‘low self control’ from psychometric tests in their 20s and 30s, would show more errors on a No-Go Task
• What was the third aim of the study?


  • to see wether low delayers would have:

  Lower activity in right pre-frontal cortex

  If they had increases activity in the ventral striatum
• What type of method was it?

  • a longitudinal experiment (happened throughout life)
  • quasi (establishes cause and effect)
  • snapshot study
• Participants?


  • 562 pupils from Bing Nursery School
  • born between 1964 and 1970
  • conducted at Stanford university
• How many people completed the self control test in their 20s?


  • 155
• How many people responded again in their 30s?


  • 135
• What is subject attrition?


  • When participants leave the study throughout it - (leads to sample bias)
• How many people were contacted due to their score being below average on the test?


  • 117
• How many people consented? (male+female)


  • 59 (23 male, 36 female)
• How many low delayers were in the marshmallow test (male+female)


  • 27 (11 male, 16 female)
• How many high delayers were in the marshmallow test? (male+female)


  • 32 (12 male, 20 female)
• What was the marshmallow test, and how were low and high delayers determined?


  • children had a marshmallow
  • eat it = no extra marshmallow
  • don’t eat it = get two
  • low delayers = ate marshmallow
  • high delayers = didn’t eat marshmallow
• Procedure?

  • Go-No-Go Tasks
  • got sent a pre-programmed laptop to their home = participants are more relaxed due to being in a home setting
  • instructions appeared on screen
  • faces appeared on screen for 500ms with 1 second delay between faces
• How many people participated in the Go-No-Go tasks in their 40s?


  • 59
• What was Cool version 1?


  • Go = male neutral face
  • No-Go = female neutral face
• What was cool version 2?


  • Go = female neutral face
  • No-Go = male neutral face
• What was hot version 1?


  • Go = happy face
  • No-Go = fearful face
• What was hot version 2?


  • Go = fearful face
  • No-Go = happy face
• How was a low delayer determined?


  • if they pressed on No-Go when they shouldn’t have
• What were the results for the cool version? %


  • 99.8% on go
• What ere the results for the hot versions? %


  • 99.5% on go
• What difference in errors made on cool tasks between high and low delayers?


  • same number of errors made, due to an unstimulated ventral striatum. (neutral face = no emotion stimulated)
• What difference of errors made on hot tasks between high and low delayers?


  • low delayers made more errors on No-Go tasks
• % of LD and HD errors on happy face?


  • LD = 15.7%
  • HD = 11.2%
• % of LD and HD errors on fearful face?


  • LD = 12%
  • HD = 10.4%
• What statistical method can be used?


  • Chi - squared - (nominal data)
• What conclusions were made?

  • Low delayers at 4 (ate marshmallow), showed more difficulty suppressing responses to No-Go presentations in 40s
  • Those classed as ‘low self control’ in their 20s and 30s, had difficulty suppressing No-Go in 40s
  • Low self control continues as they get older
• SECOND PART OF THE STUDY/


  • study of the brain
• Aim?

  • to investigate the regions of the brain, implicated in self-control
• Participants?


  • only 27 used in this part of the study
  • 12 male, 14 female
• How many high delayers used? (male+female)


  • 15 (5 male, 10 female)
• How many low delayers were used? (male+female)


  • 11 low delayers (7 male, 4 female)
• Procedure?


  • completed Go-No-Go task, but delay between each presentation was varied between 2 and 14.5 seconds
  • conducted whilst in an MRI scanner
• How many faces should have been pressed?


  • 35
• How many faces shouldn’t have been pressed?


  • 13 faces
• What had to be pressed on the first go?

  • fearful faces
• What had to be pressed on the second go?


  • happy faces.
• Results of Go trials?


  • both groups highly accurate