Casey Et Al Flashcards
Aims
To see if low delayers on the marshmallow test at age 4 still struggled with resisting temptation in adulthood.
To examine activity in areas of the brain thought to be associated with the ability to resist temptation.
Sample and final sample
The final sample was selected from the original 4 year old children in the marshmallow study.
Original 4 year old children of the marshmallow tast: 562
Young adults in their 20s for the self control scales: 155
adults in their 30s for the self control scales: 135, Casey wanted consistently high delayers and consistently low delayers ( identified as low or high delayers in marshmallow task and again on both self report measures). 117 contacted.
Final sample: 59 participants, 27 low delayers and 32 high delayers.
Opportunity sampling.
Cool task in the ‘go/no-go’ task
Cool stimuli (neutral) we’re faces with neutral expressions. In some trials, the male neutral face was the go stimuli ( and female was no go stimuli) and in other trials the female neutral face was the go stimuli and male was no go stimuli).
For the 32 high delayers
Hot task in the go-no to task
Happy go- fearful no go (had to press button when smiling face appeared and not when the fearful face appeared.
Fearful go- happy no go.
Procedure
Each participant did 4 go no go tasks on laptops delivered to their homes. Each face appeared for 500 milliseconds with a one second interval between faces.
Before the task started on screen instructions said which face was the target stimulus (male or female neutral face, happy or fearful face).
Participants were told to press the button when they saw the target face and to not press button for the other face.
They were told to respond as quickly and accurately as possible.
Results experiment 1
No difference in reaction times between high and low delayers.
Similar level of accuracy on the go trials. Both groups made more errors on no go trials.
On the hot task, low delayers performed worse than high delayers and both made similar number of errors on cool task.
Low delayers made significantly more errors on the hot task than on the cool task (similar for high delayers).
Looking at the happy face (on the task where happy face was no go), low delayers made more errors than high delayers.
This means low delayers still have difficulty resisting temptation. They show more difficulty repressing responses to the happy face as they did to the marshmallow when 4 years old.
What’s fMRI in experiment 2, how was it used?
Advantages and disadvantages.
Participants had their brains scanned whilst carrying out go no go tasks. It can be used to produce activation maps showing which parts of the brain are involved in a particular mental process as it detects changes in blood oxygenation.
Advantages: increases accuracy of measurements so improves reliability.
The only way of measuring brain activity is using technical equipment.
Makes study scientific- replicable, falsifiable.
Disadvantages: expensive
Difficult to obtain participants willing to take part.
Malfunctioning equipment and room for human error so reliability may not be as good as assumed.
Sample in experiment 2
Self selecting sample
15 high delayers (10 f 5 m)
11 low delayers (4 f 7 m)
One participant excluded for poor task performance.
Procedure in experiment 2
26 self selecting participants did the same two tasks as in the hot condition of experiment 1.
Each participant did 96 trials.
Carried out in a lab and had brain activity scanned while completing tasks.
Difference in inferior frontal gyrus (cool system) between low and high delayers.
Regulates decision making.
- low delayers found lower activity.
- High delayers could delay gratification because IFG was more active.
Difference in ventral striatum between high and low delayers.
- Low delayers showed higher activity in ventral striatum (hot system relates to emotion and desire).
- Low delayers more drawn to stimuli (smiling face) so it was harder not to press the button.
Conclusions from both experiments
- The ability to delay gratification is hindered by alluring cues and is not a general problem with cognitive control.
- FMRI results suggests physiological basis for resisting temptation which explains why some people find it harder than others.
- Provides evidence that ‘hot’ and ‘cool’ systems in the brain effects self control. Hot stimuli interfered with low delayers self control on no-go tasks (happy face).
What type of study
Longitudinal study
Used the same people who did marshmallow task as children (high and low delayers).
