Casey et al. 2011 on Delay of Gratification - localisation Flashcards
biopsychology - localisation
1
Q
Casey et al.- aim
A
- to see if ability to delay or not was a consistent personality trait.
- follow on study to see if ability to delay gratification in childhood predicts impulse control later in life
- researchers also wanted to see if ability could be linked to differences in way brain developed when resisting temptation.
2
Q
Casey et al. - design
A
- longitudinal study over period 40 years
- present part in study had 2 quasi-experiments
-IV in both was whether ppt high delayers or low delayers
-DV:
-experiment 1: DV was reaction time and accuracy on certain go/nogo tasks - testing impulse control
-experiment 2: DV was activity in target areas of brain that are associated with cognitive control
2
Q
Caseyn et al. - sample
A
- ppt selected from group of people initially tested on delayed gratification when aged 4-6 yrs old. Retested in 20s, again in 30s, and again for this study in 40s.
- experiment 1: 59 ppt selected whose self-abilities consistent in all 3 previous assessments.
- 32 high delayers: 20 women, 12 men, mean age 44.6 years
-27 low delayers: 16 women, 11 men, mean age 44.3 years - experiment 2: 27 of ppt in experiment 1 agreed to take part in study of brain activity. one ppt was excluded due to poor performance, leaving 26 ppt.
3
Q
Casey et al. - procedure
A
- EXPERIMENT 1:
1. ppt tested using laptops loaded with software then sent to use in their own homes
2. ppt given a go/no-go task - this involves first being shown a target, could be female photo. Then on each trial ppt is shown female/male photo. PPT is instructed to press button on trial where photo matches target (=go) and instructed to resist action if photo doesn’t match target (=nogo)
3. ppt instructed to respond as quick and accurate as possible.
4. photo displayed for 500 miliseconds, 1 second intervals between photos.
5. total of 160 trials presented per run in pseudo randomised order (120 go, 40 nogo)
6.each ppt took part in 2 runs - hot and cool version. In hot version ppt saw faces and emotional expressions (fearful or happy). In cool run faces were neutral. - EXPERIMENT 2:
7. only hot version was run, were 70 go and 26 nogo trials for each expression(fearful or happy)
8. brain scan used to assess brain activity while pets engaged in task using instructions and stimuli, same as experiment 1.
4
Q
Casey et al. - results
A
- EXPERIMENT 1
1. ppt who’d been able to delay gratification as children show greater ability to suppress impulse control as adults.
2. no signcf. difference between high and low delayers in terms of reaction time, nor for go trials in terms of accuracy.
3. on nogo trials low delayers performed less well than high delayers on hot tasks. Their mean false alarm rate for hot task was 12.25 and 9.965 for cool task.
4. low delayers showed decrement in performance on hot trials largely because of performance with happy nogo trials. - EXPERIMENT 2
5. variability was on nogo trials. low delayers committed more false alarms than high delayers but diff was not signf.
6. three main effect of go/nogo trials
- greater activation of right inferior frontal cortex when puts correctly inhibited a response on nogo trial
- greater activation of primary motor cortex when pets made correct response on go trial
- greater activation of left cerebellum, when ppt make a correct response on go trial
7. two main differences between high and low delayers: - nogo trial: low delayers had recused activity(relative to high delayers) in right inferior frontal cortex.
- on nogo trials with happy face low delayers had more activity ( relative to high delayers in ventral striatum
5
Q
Casey et al - conclusion
A
- consistency over time in individuals ability to regulate behaviour - the adults who had delayed gratification as children continued to do so as adults.
- differences are apparent at both behavioural and neural levels ( as shown in brain scans)
- there are important implications for cognitive control, eg. related to addiction.
