Casey

• Mischel conducted research at Stanford University looking at 600 children (age 4) who attended the stanford university nursery to see if they could resist temptation. He presented the children with a marshmallow and said they could eat the marshmallow or wait 15 minutes and have 2 marshmallows. One third of the children delayed gratification long enough to receive the second marshmallow through mechanisms such as distracting themselves.

  He labelled these children as high delayers and the other children as low delayers.
• Casey wanted to build on Mischel's research by conducting a follow up study on the participants of the marshmallow test to see if they children were also high/low delayers in adulthood. To do this she developed a go/nogo task to measure impulse control.
• Casey aimed to build on previous research to assess whether delay of gratification in childhood predicts impulse control activities in adults. The study looks at impulse control on a behavioural level (if they press the button or not) and a neural level (brain activity). They also wanted to look at sensitivity to alluring social cues.
• In experiment 1:

  • Casey studied 59 participants taken from the original sample of Mischel, now aged 40. It was a mixture of high/low delayers and men/women.

  In experiment 2:

  • 27 of the participants in experiment 1 agreed to take part.
• In experiment 1, participants were provided with laptops with the Nimstim set of faces where an image of a face flashed for 0.5 seconds. They were given 2 go/nogo tasks:

  1. cool - neutral faces and the task was to press the button for a given gender face and ignore the other gender face.
  2. hot - participants were shown happy and fearful faces and were told which one would be the go stimulus (i.e press the button when they see).

  In both conditions, participants were told to answer as fast as possible. There were 160 trails per run, presented in a random order.
• In experiment 1, Casey found:

  • High and low delayers were not significantly different in the accuracy and reaction times on the go trails.
  • Low delayers made significantly more false alarms on the nogo trails especially in the hot tasks.

  In experiment 2, she found:

  • Low delayers had reduced activity in the inferior frontal gyrus on no go trials.
  • Low delayers had increased activity in the ventral striatum on no go trials.
• Casey concluded:

  • The more alluring a social cue (e.g. a happy face) the harder it is to resist the temptation of that stimuli.
  • Low delayers in childhood as adults have a hard time implementing impulse control.
  • Resistance to temptation is a relatively stable individual difference.
• In experiment 2, only the hot task was completed but the participants were getting an fMRI during it. This measured brain activity. The images of the happy/fearful faces were projected using E-Prime software.