Casey et al Flashcards
What is the aim of this study?
to investigate if delay of gratification in childhood can predict impulse control and sensitivity to alluring social cues at the behavioural and neural age of 40
What is the research method for the study?
quasi experiment
Why is this a quasi?
because whether a person is a high or low delayer is naturally occurring and cannot be directly manipulated by the researcher
What are the strengths of a quasi?
- behaviour is more natural as cannot be manipulated
What are the weaknesses of a quasi?
- lack of control over EVs
What is the DV?
performance on the impulse control and cognitive go/ no go task
What are the two components of the DV?
accuracy (false alarms) and reaction times (speed)
What is the design for the study?
repeated measures
Why is it a repeated measures design?
same people doing tasks at different ages
What is a strength of repeated measures?
- smaller sample needed
What are weaknesses of repeated measures?
- order effects are more likely
- demand characteristics are more likely
What scientific machinery was used in experiment 2?
fMRI scan
What type of methodology was used?
longitudinal
Why is using longitudinal methodology a strength?
can see the changes in delay of gratification over time
What was the original sample before the main study?
562, 4 year olds from Stanford’s Bing Nursery School
What was the task that the 4 year olds did?
Marshmallow test (delay of gratification task)
What was the sample when the same set of 4 year olds were in their 20s?
155
What was the task that the 20 year olds completed?
self-control questionnaires
What was the sample for the participants when they were in their 30s?
135
What was the task that the 30 year olds completed?
another self-control questionnaire
What was the method for some of the follow up tasks (20s & 30s)?
self-report (questionnaire)
What are the strengths of a self-report method?
quick and easy to complete
What are the weaknesses of a self-report method?
social desirability bias - lying to impress researcher
How many participants did Casey contact for the main study?
117
Why were the participants selected?
they were individuals who were consistently high or low delayers across all 3 tests
How many of the 117 contacted agreed to take part in experiment 1?
59
- 23 male
- 36 female
How many of the 59 from experiment 1 agreed to take part in experiment 2?
27
- 13 male
- 14 female
Why was experiment 2 really only 26 participants?
one 41 year old man was excluded from all analysis as he had poor performance (an outlier)
What are the strengths of the sample?
- initially really large = representative & generalisable
- no gender bias includes males and females
What are the weaknesses of the sample?
- high rate of attrition
- ethnocentric (only USA)
- lacks population validity
What is experiment 1?
the longitudinal behavioural study
What is experiment 2?
the functional neuroimaging study
What was the purpose of experiment 1?
to test whether delay of gratification was a stable behavioural characteristic
How were children who were low delayers expected to behave as adults?
show less impulse control
What materials were the 59 participants given?
a programmed laptop to use at home and complete two versions of the go/ no go tasks
What were the two versions of the go/ no go tasks called?
cool and hot
What was the premise of the cool version?
- male and female face
- neutral face expression
- participants told which sex was the ‘go’
- press button every time they saw their target
- other sex = no go and should NOT press button in response to this face
What was the premise of the hot version?
- identical to the cool version EXCEPT facial expressions
- happy or fearful facial expression
- alluring stimuli
What were the timings for the procedure? How long were the faces shown for? What was the interval between pictures?
1) Photos shown for 500ms
2) Interval = 1s
How many trials were there total and what was the ratio of go and no-go?
160 total trials (pseudorandomised) 120 go & 40 no go
How can the procedure be criticised?
- Lacks mundane realism
- Causality CANNOT be established (took place at participants home) = less control (EVs)
What are the strengths of the procedure?
Extremely standardised = more reliable & replicable
What was the purpose of experiment 2?
to examine the neural correlates of delay of gratification
What was predicted before experiment 2?
That low delayers would show diminished activity in the inferior frontal gyrus and amplified activity in the ventral striatum compared to high delayers
What version of the go/no-go task did participants in experiment 2 complete?
hot
Why was only the hot version of the go/no-go task used in experiment 2/
To see the differences between high and low delayers as they performed similarly on the cool version
What was different from experiment 1 in regards to the task?
there was a jittered interval ranging from 2-14.5 s (rather than the standardised 1s)
How did participants complete the go/no-go task whilst in the fMRI scanner?
A Neuroscreen five-button response pad (recorded responses and reaction times)
How many trials were run in experiment 2 and what was the ratio of go and no go?
48 total trials - 35 go and 13 no-go
How was the task viewable to experimenters?
a projector screen
What type of data was gathered (across all 4 experiments)?
quantitative
What are the strengths of quantitative data?
- objective
- easy to compare and analyse
What are the weaknesses of quantitative data?
- no reasoning behind behaviour
What were the key findings from experiment 1 in context of the ‘go’ trials?
- there was no effect of being a high or low delayer on reaction times
- participants performed with a high level of accuracy for both cool (99.8%) and hot (99.5%)
What are the key findings for experiment 1 in the context of the ‘no-go’ trials?
- Low delayers made more false alarms therefore were LESS accurate (false alarms in cool = 10% & hot= 12%; more difficulty suppressing immediate response from ventral striatum
- Low and High delayers performed similarly on cool tasks
- Low Delayers performed poorly on the hot tasks - difference more pronounced when shown happy faces (emotional hot cues)
- Low delayers found no-go trials more difficult than high delayers
SHOULD BE NOTED: high delayers still make notable mistakes however low delayers were more significant
What are the key findings from experiment 2 in the context of the ‘go’ trials?
- high and low delayers did not differ significantly in reaction times
- Overall accuracy rates for the ‘hot’ condition were uniformly high
What were the key findings from experiment 2 in the context of the ‘no-go’ trials?
similar results as experiment 1 with low delayers committing more false alarms than high delayers
What were the key findings of the fMRI scans in experiment 2?
- identified that the inferior frontal gyrus was involved in accurately withholding a response (low delayers have diminished recruitment)
- Low delayers have diminished recruitment for ‘happy’ faces compared to ‘fearful’ faces
- identified the ventral striatum (rewards) was involved in immediate responses (low delayers had increased recruitment)
What conclusions can be drawn from the study?
- individuals at 4 years old who have difficulty delaying gratification continue to show self-control abilities and have more difficulty suppressing responses to positive social cues
- Resistance is a stable characteristic (criterion validity)
- The capacity to resist varies by context
- Sensitivity to environmental hot cues play a significant role in an individuals role to suppress actions towards alluring cues
What are the ethical issues within the study?
STRENGTHS:
- informed consent
- ethical (non-harmful or risky) procedure
WEAKNESS:
- socially sensitive - creates self fulfilling prophecy (act up to labels)
