Li et al. (2013)-evaluation

Question 1

what is a strength of this study ?

Answer 1

• high standardisation of procedures
• e.g. ppt saw the same heroin-related and neutral images which were all presented for 2 seconds
• fMRI protocols were all the same for each ppt (e.g. each resting-state scan took five minutes)
• procedure identical for each ppt
• researchers controlled for potential confounding variables, giving the the study a greater internal validity

Question 2

what is a competing argument to the study’s standardisation ?

Answer 2

• some procedures were inadequate
• e.g. sample sizes were small (just 14 heroin users)
• increased chances of making a type 1 statistical error (finding a significant result when none existed)
• the differences in brain activation between the heroin users and controls may not have been genuine

Question 3

what is a weakness of this study ?

Answer 3

• confounding variable in the study (influence of nicotine)
• all ppts in the study (including the controls were smokers)
• researchers claim they accounted for this by showing there was no difference between the two groups in scores of a test of nicotine dependence
• this ignores the potential influence of an interaction between nicotine and heroin which would occur in the heroin group but not the control group
• there is evidence that nicotine and heroin interact biochemically (e.g. Kohut 2017)
• this would make it a confounding variable as it was a systematic difference between the two groups

Question 4

what is an application of this study ?

Answer 4

• could lead to improvements in diagnosing Brian damage in heroin addicts
• researchers found that abnormal functional activity involving the PCC was associated with the extent of a user’s heroin dependence
• if this finding is reliable then functional connectivity could therefore be used as a biomarker (biological indicator) of brain damage in heroin addicts
• this means that fMRI scans similar to those used in the study could establish a severity of brain damage in heroin users
• this could be the first step to providing a treatment or at least preventing further damage

Question 5

what did Kohut (2017) find evidence for ?

Answer 5

found evidence that nicotine and heroin interact biochemically