14- Casey et al: BIOLOGICAL Flashcards
Aims
Aimed to see if the 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
Ability could be linked to differences in way brain behaved when resisting temptation
Background
The marshmallow test.
-> 1970s Walter Mischel investigated the ability to defer gratification.
-> Involved almost 600 children aged between 4 and 6 yrs old.
-> A child would be seated at a table in a room with a researcher.
-< The researcher offered the child one marshmallow but could have 2 if the child waited for 15 minutes.
-> The researcher then left the room and returned after the allotted time.
-> By the time 15 minutes were up 2/3 of the children had succumbed and eaten them.
Results of background research
Some children were:
-> High delayers:
Meaning they could wait and received the reward of 2 marshmallows.
-> Low delayers:
Who could not wait and took the immediate reward by eating the marshmallow.
Definition of “hot” cues
Elicit an instant, emotional response.
Rewarding hot cues are linked with our desires and positive emotions.
Definitions of “cool” cues
Takes the emotion away from a stimulus. Not emotionally rewarding -> neutral.
What did Metcalfe and Mischel (1999) suggest?
There is a “cool” system in our brain locate in the pre-frontal cortex.
-> Area is called the INFERIOR FRONTAL GYRUS
* This area is associated with deciding whether to resist or not (MORE active in high delayers).
-> The “hot” system which is related to emotion and desires is in different areas.
* One part of this is called the VENTRAL STRIATUM
* This is related with emotion, desires and rewards. This would be MORE active in LOW delayers.
Summary:
-> Cool = prefrontal cortex = inferior frontal gyrus = high delayers
-> Hot = ventral striatum = related to emotion = low delayers
What are fMRI scans?
A brain imaging technique which scans the brain using magnetic and radio waves.
It is designed to investigate the anatomy of the brain (its structure).
A computer converts this into an image.
What is meant by delayed gratification?
Ability to resist a reward in the present for a greater reward in the future.
The degree of people’s ability to delay gratification can be measured at an early age and can predict later life success.
It depends on cognitive control.
What is meant by cognitive control?
Our ability to suppress competing inappropriate thoughts or actions in favour of appropriate ones.
Research questions
- Would children identified as LOW DELAYERS at age 4 show an inability to exert self-control in adulthood?
- Will there be a difference in adults brain activity between LOW DELAYERS and HIGH DELAYERS?
Design
Repeated measures design.
Method
Quasi experiment
Longitudinal study - (4 to 40 years)
IV
Both;
Ps high delayers or low delayers
DV
1: reaction time and accuracy on go no go task = performance on the impulse control task
2: activity in target areas of brain that are associated with cognitive control = fMRI imaging results
Sample
Selected from sample of 562 Ps who completed the marshmallow test at age 4.
Retested in 20s 30s:
* 20s = 155Ps completed a self-report on the self-control.
* 30s = 135 Ps repeated self-control.
Exp 1:
59 participants:
-> Self-selected = sent letters asking them to volunteer.
* 32 high delayers = 20 women, 12 men, 44.6 years
- 27 low delayers = 16 women, 11 men, age 44.3 years
Experiment 2:
27 Ps from exp 1 agreed take part, 26 took part
Results
Experiment 1
Hot test (quantitative)
Both groups performed similar on the fear face no-go trials.
Low delayers produced significantly more errors on the happy no-go trial.
DATA SHOWN IN PICTURE
