Casey Flashcards
What were they investigating?
Areas of the brain involved in delay of gratification.
Roles of different areas of the brain, similar to sperrys.
Context
Originally looked at child to see if they were good at resisting temptation or not, wanted to see if this was same when they were in their 20s and 30s.
Also did fMRI scans (high res images of brain) on them when they were older.
Children’s test on delaying gratification
-40 years ago sample of 4 year old children performed delay of gratification task.
-children were led into a room, a treat (marshmallow) was placed on table.
-children could eat the treat, but if they waited 15 mins without giving into temptation, they were rewarded a second treat.
-some covered their eyes, turned around so they could not see treat, others kicked desk, touched treat and some simply ate it as soon as researchers left.
-of those who attempted to delay, 1/3 deferred gratification long enough to get the second marshmallow.
Delay gratification
How we are able/ or not able to resist temptation.
resisting= delaying gratification
biological psychologists interested in what brain processes and areas are involved in resisting and giving in to temptation.
Inferior frontal gyrus
Located in frontal lobe.Part of frontal gyrus, constituted large part of ventrolateral surface of prefrontal cortex.
Right frontal gyrus is implicated in go/no go tasks- involved in cognitive control process that helps inhibit/delay responses.
‘cooling system’ in brain involved in deciding whether to resist or not.
Ventral striatum
Brains pleasure centre- ‘hot’ system related to emotions and desires.
Plays crucial role in reward and motivation.
This region is active during anticipation and receipt of monetary and social rewards.
Positive emotional stimuli activate ventral striatum as do feelings of social connection, interpersonal warmth and feeling understood.
fMRI (functional magnetic resonance imaging)
Measure changes in blood oxygen levels connected to neural activity in brain or spinal cord.
Detailed brain imaging, recently developed.
high temptation-focus children
Those who found it difficult to resist
low temptation-focus children
used cognitive strategies that redirected their attention such as ‘cooling’ appealing features of tempting stimuli by reappraising or reframing strategies.
high delayers
naturally focus on cold cues, resist temptation
‘hot’ system’ Metcalfe and Mischel
relates to desires and emotions
‘cool system’ Metcalfe and Mischel
based on cognitive control
What did Casey et al show?
That cognitive control that aids gratification delay may be linked to inferior frontal gyrus, as opposed to limbic (emotional) region linked with ‘hot’ cues
Aims
To build on previous research to assess whether delay of gratification in childhood predicts impulse and self control abilities at the behavioural and neural level in adulthood.
Sensitivity to social cues (happy faces) was also tested.
Sample: original study
562 children aged 4
Sample: self report 1993
155 of sample
Sample: self report 2003
135 of sample
Experiment 1 sample
59 of 117 asked
Experiment 2 sample
27 of 59 asked
Original study
562 4 year olds from Stanford Bing Nursery School took part in experiment to delay gratification with a marshmallow.
1993 self report
155 of the original sample completed a self report measuring self control, it was a shortened version of the California Child Q-set.( a questionnaire to test self control).
2003 self report
135 of the original sample were given the report again when they were in their 30s.
2011 experiment 1
117 of the previous 135 ps were contacted to take part in exp 1, 59 gave consent
23 males
36 females
27 agreed to have an fMRI scan (13 male, 14 female) 1 man excluded for poor performance (26 ps).
Research method
Quasi experiment- IV naturally occurring (high delayer or low delayer)
Repeated measures, everyone asked back was used in first observation, no new people introduced.
Also independent measures as ps were either high or low delayers, could not be both.
IV
high delayer (can wait)
low delayer (cannot wait)
DVs
Exp 1- ps performance on impulse tasks in terms of reaction times & accuracy (go/no go tasks)
Exp 2- same as exp 1 but had fMRI whilst doing task showing brain regions involved in delay of gratification.
Controls
All apparatus the same; go/no go tasks were all same; all timings same; presented in pseudorandomised order; each face appeared for 5ms; same aged children in first study (4 years old) all sent laptops and used inquisit software; same faces shown; all from same nursery school; all completed same self report; same emotions shown; same factors measured from each experiment.
Go/ no go tasks (include hot/cool tasks)
You have to press button as fast as you can when you see a certain image.
‘go’ condition
you actively pressing button
‘no-go’ condition
shown a different image and have to stop yourself from pressing the button.
‘cool’ version of go/ no go tasks
male and female faces with neutral expressions were presented.
‘hot’ version of go/ no go tasks
happy and fearful faces of males and females presented.
other apparatus: Laptops
Inquisit software loaded onto laptops; general electric signa3.0-T fMRI scanner with an eight channel head coil.
Experiment 1
-59 ps tested
-laptop loaded with software at peoples home
-given go/no go task, first shown a target
then,on each trial, ps shown male or female photo.
-instructed to press button on any trial where photo matches target (go)
-instructed to resist photo that does not match (no go)
-told to respond as quickly and accurately as possible
-each face appeared for 500ms with 1 sec interval between photos
-160 trials presented in total in pseudorandomised order; 120 GO, 40 NO GO.
-each ps took part in 2 runs (hot and cool version)
Results of experiment 1
No significant difference in high and low delayers in terms of reaction times on the GO trials. (did not matter if you were high/low delayer when pressing button during ‘go’ trials)
Ps performed high level of accuracy for correctly
responding to ‘go’ trials during hot and cool.
Accuracy for ‘no go’ trials was much less, especially for low delayers.
Low and high delayers performed same accuracy for COOl tasks, But high delayers did better in HOT tasks- low delayers made many mistakes.
Overall, go/no go task produced differences between delay groups only in presence of emotional ‘hot’ cues.
Low delayers showed more difficulty in supressing response to happy faces than high delayers did.
Experiment 2
-27 ps from 59 ps in exp1 took part (1 excluded)
-was expected that low delayers would show less activity in right prefrontal cortex and more in ventral striatum compared to high delayers.
-Tested this using fMRI to see areas of brain used in delaying gratification tasks.
-Ps completed hot version (fearful + happy faces) of go/no go tasks, similar to exp 1.
-timings, number of trials and apparatus used were different
-500ms, jittered interrail intervals ranging from 2-14.5 seconds
-48 trials were presented per run in pseudorandomised order.
-ps were only scanned on the ‘hot’ task as in exp 1 no differences were found between low and high delayers on the cool task.
Experiment 2 Results
Both delay groups did not differ significantly in reaction times in correct ‘go’ trials.
Overall accuracy for ‘hot’ go/no go task was high for go trials, more variable performance to no-go trials.
Low delay ps had more false alarms than high delayers.
Imaging results of experiment 2
There were different brain areas involved in delay of gratification.
Right inferior frontal cortex: Reduced activity in low delayers on no go trials compared to high delayers.
Ventral Striatum: Interaction between group type, trial type and emotion: more activity in this region in low delayers than high on no go trials when shown happy face (hot).
Inferior frontal gyrus
‘COOL’ system in our brain linked to cognitive control.
associated with deciding to resist or not.
MORE active in HIGH delayers
LESS active in LOW delayers.
Ventral Striatum
‘HOT’ system related to emotion and desires, related to responding to positive emotions and rewards.
MORE active in LOW delayers.
LESS active in HIGH delayers.
More alluring the stimulus (i.e context) the more difficult low delayers find it to resist. (smiley/ fearful face)
Conclusions
-Resistance to temptation is relatively stable characteristic of an individual over time.
-Capacity to resist temptation (cognitive control) can be strongly influenced by contextual factors.
-Individuals at 4 years old who struggled to delay gratification have more difficulty as adults in suppressing responses to positive social cues than those who did not.
-Ability to resist temptation is supported by neural networks in brain; low delayers have less activity in inferior frontal gyrus and increased activity in ventral striatum.
