Casey

• background

  • ifg - reduces the excitement and rewarding look of the stimuli and enables cognitive control
  • vs - becomes active when we see an exciting temptation, overrides the cooling system
  • mischels marshmallow test - 600 children, experimenter tells child they could have a second marshmallow of the wait.
• aim - investigate the extent to which the ability to resist is a consistent trait in adults
• predictions

  1. low delayers would show more errors on go/no go tasks if the stimuli were hot than high delayers
  2. low delayers would show lower activity in the IFG and higher activity in the VS
• method

  • longitudinal
  • self report in 20s and 30s
  • both experiments repeated measures design and the same self report was used twice
• sample

  • 562 ps aged 4
  • 155 self report 1 (aged 20)
  • 135 self report 2 (aged 30)
  • 59 in e1
  • 26 in e2
• procedure e1

  1. ps completed the go/no go tasks in which faces were shown on a laptop delivered to ps homes
  2. each face appeared for 500ms
  3. before each task instructions appeared telling ps which face was the target stimulus, ps were told to press a button for the target stimulus and respond as quick as possible
• go/ no go tasks e1

  • cool - male neutral face (go) female neutral face (no go)
  • cool - female neutral face (go) male neutral face (no go)
  • hot - happy expression (go) fearful expression (no go)
  • hot - fearful expression (go) happy expression (no go)
• results

  • both groups performed with high level of accuracy on the go trials in both hot and cool versions
  • both made errors on the no go tasks, low delayers made more errors on the happy trials
• conclusions e1

  • low dealers who had shown more difficulty in delaying gratification aged 4 showed more difficultly suppressing responses to happy faces in their forties. Self control is a relatively consistent feature
• aim e2 - investigate the regions of the brain that they predicted would be involved in self control
• procedure e2

  1. ps completed the same go/no go trials in the fMRI machine
• results e2

  • low delayers showed lower activity in the right IFG, suggesting this region plays a role in withholding of a response
  • low delayers showed higher activity in the VS, specifically when happy faces were the no go, showing the alluring qualities of a stimulus affect cognitive control ability
• conclusions

  • resisting temptation is a relatively stable individual characteristic
  • delay gratification is hindered by alluring cues, is not a general problem with cognitive control
  • empirical support for hot and cool processing systems that affect self-control
• strengths

  • self report is highly standardised
  • useful applications
  • reliable
• weakness

  • demand characteristics
  • reduced ecological validity
  • low mundane realism
  • unrepresentative sample
• relate to regions of the brain key theme

  • low delayers have less activity in the IFG than high delayers on no go trials, suggesting brain region plays a key role in withholding of a response
• relate to biological area

  • assumption - behaviour should be studied scientifically
  • uses an fMRI machine which is objective
• similarities between sperry

  • high standardisation
  • both ethical
• differences between sperry

  • Casey = longitudinal, sperry = snap shot
  • sperry gathered quant and quali data, Casey quant only