A-level psychology: Casey et al

biological approach- delay gratification

what was the sample for Casey's background study?

562 4 year olds from Stanford Bing nursery school 1960/70

how many from the original children in Caseys background study were studied in their 20s?

155 of the original 562 were studied on their 20s 1993

hoe many from the original children in Caseys background study were studied in their 30s?

135 of the original 562 were studied in their 30s 2003

what kind of study was Casey's background study?

it was a longitudinal study because it was conducted over a long period of time

what was the task given to the children in Casey's background study and what was it called?

it was a gratification task and each child was given a marshmallow and were told to wait until the teacher came back before they could eat it. if they waited they would be rewarded another marshmallow

what was the child who waited labelled as?

a high delayer

what was the child who didn't wait labelled as?

a low delayer

what method was used in experiment one in Casey's study?

quasi experiment, naturally occurring iv

where did experiment one take place in Casey's study?

the participants' homes

what was the sample in experiment one in Casey's study?

59 participants, 23 males and 36 females had consented to take part out of the 117 who were contacted

they were categorised as high or low delayers based on the gratification task

how many participants were high and low delayers in experiment one?

32 were high delayers, 12 males and 20 females

27 were low delayers, 11 males and 16 females

what was the procedure in experiment one testing?

it tested whether individuals who were less able to delay gratification as children and young adults would do the same as adults in their 40s- to show less impulse control in suppression response to 'hot' and 'cool' cues

what was the go and no-go cool tasks in experiment one?

the cool no-go task consisted of male and female stimuli which were presented to the participants. one sex as 'go' stimuli in which the participants were instructed to press a button

the other sex would be a 'no-go' stimuli and the participants were instructed to withhold from pressing the button

how long did each face appear for in experiment one and how long was the inter stimulus between the pictures?

each face appeared for 500ms which was followed by a 1 second inter stimulus interval

how many trials were presented and in what order in experiment one?

a total of 160 trials were presented in a randomised order

how many go and no-go tasks were there in experiment one?

120 go and 40 no-go

what was the go and no-go 'hot' tasks in experiment one?

the 'hot' version of the go and no-go task was identical to the 'cool' version the only difference was that the stimuli were fearful and happy facial expressions

how were the tasks in experiment one presented?

they were presented on a programmed laptop which was sent to participants' homes

what was the method used in experiment two?

quasi experiment, naturally occurring iv

what was the sample for experiment two in Casey's study?

from the 59 who took part in experiment one there were 27 who took part in experiment two- 13 males and 14 females

how many people from experiment two's sample were high and low delayers?

15 were high delayers and 11 were low delayers

why did the sample in experiment two go from 27 to 26?

one man was excluded from the sample due to an abnormally low performance

what was the procedure in experiment two testing?

a machine was used to examine neural correlations of delay gratification, it was anticipated that low delayers would show less activity in the right prefrontal cortex and had more activity in the ventral striatum compared to high delayers

what machine was used in experiment two?

an FMRI scanner

what was the task given to the participants in experiment two?

participants completed a 'hot' version of the go and no-go task similar to the one used in experiment one, however the timing, number of trials and apparatus changed

how long was each stimuli presented and how long was the inter-trial interval in experiment two?

each face stimuli was shown for 500ms which was followed by a inter-trial interval ranging from 2-14.5 seconds in duration

how many trials were presented and in what order in experiment two?

a total of 48 trials were presented in a randomised order

how many go and no-go tasks were done in experiment two?

35 go and 13 no-go tasks

how was the task shown in experiment two?

the task was shown by a rear projection screen and a neuroscreen, a 5 button response pad recorded the button responses and reaction times from inside the scanner

what is a neuroscreen?

a screen which the participants can view from the FMRI scanner

what were the results for reaction times in experiment one?

there was no effect of delay type on the reaction times of the participants

what was the results for the accuracy for go trials?

low and high delayers performed with comparable accuracy on 'go' trials,

cool: 99.8%

hot: 99.5%

what were the results for the accuracy for the no-go trials in experiment one?

accuracy for 'no-go' trials varied with low delayers committing more false alarms than high delayers

what were the results for reaction times in experiment two?

reaction times didn't differ significantly

what were the results for the accuracy in experiment two for the hot go and no-go trials?

overall accuracy for the 'hot' go and no go tasks was high for the go trials with 98.2% being correct

but there was more variable performance in the 'no-go' trials with 12.4% of the responses being false alarms

who committed more false alarms in both experiments?

low delayers

what results were shown in the imaging results for the right inferior frontal gyrus and the 'go' and 'no-go' trials?

the scan showed that it was involved in accurately withholding a response and compared with high delayers, low delayers had less recruitment of the frontal gyrus for the correct 'no-go' trials in comparison to 'go' trials

what results were shown in the imaging results for the ventral striatum and the 'go and 'no-go' trials?

the scan showed that it demonstrated significant difference in recruitment between high and low delayers. it elevated activity to happy 'no-go' trials for low delayers in comparison to high delayers

where in the brain did low delayers have more activity?

ventral striatum

where in the brain did high delayers have more activity?

right inferior frontal gyrus