Casey Flashcards
Define delayed gratification
Resistance to temptation of an immediate pleasure in the hope of obtaining valuable reward in the long term
Define conitive control
Ability to suppress copeting innappropriate thoughts or actions in favour of appropriate ones
What is the function of cognitive control
Aids delayed gratification mauy be linked to teh inferior frontal gyrus loacted in the pre frontal cortex.
Aim
To investiaget teh extent to whch teh ability ot resist temptation at preschool age affected the same partciapnts in adulthood. Control over impulses nd sensitivty to scoial cues at the behavioural and neural level were examied
Mthod
Longitudinal tracking the same partcipants from age 4 until 40s
Design
2 Natural Quasi Experiments as the IV naturally occuring
Partciapnts
Ppts selected from the original cohort of 562 children who did the marshmallow test (1960s.)
-155 of these completed self-control scales in their 20s (1993), then 135 of these when in their 30s (2003)
.-117 of the 135 individuals were contacted in relation to participating in this study.
-In Experiment 1 there were 32 high delayers (12 m, 20 f) and 27 low delayers (11 m, 16 f).
- In exepreiemtn 2, 15 high delayers and 11 low delayers
Procedure of experimnt 1
Completed in own homes with pre programmed laptop
Instructions to either press a buton (go) r withhold from pressing (no go)
Cool included the presentation fo afecs. One sex was go
Partcipants given instructions ot reposnd quickly
Each face appeared from 500 milliseconds followed by a one second interval
160 trials used in a random order.
The hot task varied by facial expressions only
Procedure of experiment 2
partciapnts scanned with fmri whilst completing a hot version fo go/no go task
an electronic reponse pad was used ot record reposnses to facial stimuli an dreaction times
48 trials presented during each run
Each face appeared for 500 milliseconds followed by intervals ranging from 2 seconds to 14.5 seconds.
Reserachers colleced imaging data for 26 no go trials adn 70 go trials per facial expression
Results of experiment 1
Both groups highly accurate in their correct reposnses to go trails in both cool and hot conditions. (99.8 and 99.5%)
Low delayers were slightly more likely to repond mistakenly in the no go trials and perfromed slightly worse than high delayer in the hot version fo the task
Low delayers identified at 4 years of age showed greater difficulty suppressing their reposnes to happy fces than highdelayer
Results in experiemnt 2
No significant difference between the two delay groups on reaction times in correct go trials.
-Accuracy across both group were very high for go trials.
-Low delayers had higher false-alarm rates in the no-go trials
-LD had reduced activity in Inferior frontal gyrus compared to HD during gotrials (The right inferior gyrus appeared to be critical in withholding reponses with ld showing reduced actvity in this in the no go trials)
-High levels of activity in the Ventral striatum for LD compared to HD (mostly during the happy no-go trials for LD)
The ventral striatum is the reward realted region
Samplein exepriemnt 11
32 hd
27 ld
sample in experiment 2
15 hd
1 ld
Conclusion
Resistance to temptation is a relatively stable characteristc of an indivdual over itme
Cogntie control can be strongly influenced by contenxtual factors (e.g hot cues in alluring situations)
Ventral frontalstriatal circuitry supports resiatnce to temptation, with a combination of lowered actvity in their inferior frontal gyrus and increased actvity in the ventral striatum in ld
Validity: Strengths
he study was highly internally valid due to the high use of controls and standardisation in both experiments. The controlled extraneous variables allowed conclusions to be drawn about the independent variable of being a low or high delayer age 4 causing the dependent variable of behaviour in impulse control tasks.
Validity wekanesses
As the first experiment occured in participant’s homes, there could be extraneous variables present which were not controlled and individual differences between participants based on their own home environments.
This could reduce internal validity as one of these factors could have caused the dependent variable, rather than the independent variable.
Moreover, as the study was a quasi experiment there was a naturally occuring IV and this could not be manipulated. Low delayers may have had more difficulty paying attention when doing the tasks and this may have affected their performancerather than their impulse control. They may also have personality traits such as being more assertive or aggressive and this could cause them to press go on no-go stimuli.
Demand Characteristics
Demand characteristics and social desirability are unlikely to have affected results as behaviour remained constant over the 40 years.
What extraneous varibales were controlled adn how
Extraneous variables which were controlled were the equipment in the experiments. In the first experiment, there was a carefully standardised programme used on the laptops used by participants to present stimuli and record responses. It was therefore higgly accurate and standardised because the software used for the go/no-go tasks allowed reactions and their times to be recorded with high accuracy, thus avoiding human error. The second experiment occurred under laboratory conditions and therefore any extraneous variables e.g. noise were controlled. This experiment also gained highly valid data as the fMRI scanner directly observed empirical evidence of brain activity. These were highly objective and therefore allowed conclusions to be drawn about brain activity and being a low/high delayer affecting behaviour in impulse control tasks. This provided the study with high internal validity.
Any uncontrolled extraneous vairbales
As experiment 1 took place in participant’s own homes, there may be uncontrolled extraneous variables depending on the home environments of participants e.g. if anyone was in the room with them when they did the task, what time they did the task, background noise, other distractions etc. Therefore there is a possible risk of extraneous variables affecting the performance of participants. There may also be participant variables and this is more of a problem in quasi experiments as participants cannot be given a condition randomly as the conditions of being a high or low delayer are naturally occuring.
Ecological validity
Weaknesses: The ecological validity of this study can be considered to be low. The nature of the go/no-go tasks was artificial and in real life, we would not normally encounter and respond to facial expressions in this way. Moreover, it cannot be said that the facial expressions were even measuring impulse control in the participants and perhaps a different stimuli would have been more effective and appealing. Themundane and experimental realism of experiment 1 is low as participants would never do a go/no-go task in everyday life. The fMRI scanning done in experiment 2 is also low in mundane realism as it is an uncomfortable experience which isn’t something one does as an everyday activity. The scanner may have impacted on how participants responded to the faces shown in the impulse control tasks. Real life social interactions are much more complex than the tasks presented in this study and our brains may behave differently in these situations compared to the way they behave under artificial conditions. Therefore, the study is ungeneralisable to everyday life and is very low in ecological validity.
Internal reliability: Strengths
Strengths: Casey’s study showed that from 4 years to 40 years of age, participants remained consistent in being a low or high delayer so findings from measures within the study are consistent.Moreover, Casey demonstrated that there were consistent results between experiment 1 and 2 in terms of the percentage of errors made betweenthe high and low delayers. Low delayers had slightly more errors in both experiments so this was consistent. We can say the internal reliability of the study was high
Internal relaibility: Weaknesses
Weaknesses: It is difficult to recreate Casey’s study from 4 years to 40 years as it is longitudinal and this would be expensive to replicate so it is hard to measure whether the results would be consistent again between both experiments if the study was repeated.
External reliability: Weaknesses
Weaknesses: Due to the longitudinal nature of the study, it is difficult to replicate in order to check the reliability of the study. This would require starting with 4 year olds and following them into their 40s and would be neither time or cost effective. Therefore, we cannot prove the reliability of Casey’s findings easily.
External reliability: Strengths
Strengths: The experiments are highly standardised so if replicated, results are likely to be similar. Experiment 2 occurs in a laboratory setting and was therefore highly controlled so the method in the study is reliable. The fMRI scanner being used to measure activity in the ventral striatum and the right interior frontal gyrus meant if replicated using the same equipment, the experiment would likely lead to consistent results. Therefore we can say Casey’s study is fairly reliable in terms of the actual experiments.