Cue Reactivity

Intro
'addiction is caused primarily by drug-induced sensitization in the brain mesocorticolimbic systems that attribute incentive salience to reward-associated stimuli. If rendered hypersensitive, these systems cause pathological incentive motivation (‘wanting’) for drugs' (Robinson and Berridge 1993, 2000). The area of focus for our experiment was to investigate if Robinson and Berridge's incentive-sensitisation theory extended to mere social drinking students, measuring the physiological effects of alcohol related stimuli on our participants. The theory suggests that physiological reactivity is prompted by drug-related cues which increase dopamine neurotransmission in the mesocorticolimbic system thought of as a 'reward' pathway in the brain. If a newly recovering alcoholic was to see a bottle their favourite type of alcohol on the street it is though that there would be a relatively large physiological response, as this particular cue-related stimulus would have high salience and therefore grab the individual's attention.
It is important to investigate the difference between social/recreational drug users and those with problems of addiction through physiological analysis, to understand the biological effects on individuals depending on their drug usage and potentially an indicator of an individual’s relationship with a drug.
Positive reinforcement in drug use refers to the ‘high’ users feel suggesting they are motivated by chasing the euphoria their drug brings, whereas negative reinforcement refers to a user taking their drug substance of choice to escape the

method
A within groups experimental design was used to test both sets of hypotheses, 72 2nd year psychology students participated as part of their course which consisted of 5 males and 67 females. The mean age of participants was 20.18 years with a standard deviation of 1.86 within the sample. The dependent variable on the first level of the experiment was Heart-rate (HR), and on the second level the dependent variable was the Galvanic Skin Rate (GSR) response. The independent variable on both levels of the experiment was picture type, with their being a neutral stimulus and an alcohol related stimulus.
A Biopac system was used to measure HR and GSR this consisted of two PC’s and monitors side by side with one being connected to BIOPAC student lab software itself, and the other monitor displaying the PowerPoint presentation. The BIOPAC GSR transducer and BIOPAC ECG electrode lead set connect to the BIOPAC data acquisition unit which relays information to the lab software. 3 Disposable vinyl electrodes were also used per participant. 12 pictures were used with 6 being neutral non related to alcohol such as a table or wardrobe with the other 6 being alcohol related, e.g. somebody drinking a glass of wine.
The Biopac system measured both levels of dependent variable simultaneously, the SS2L electrode lead set from the Biopac MP30 unit were connected to the participants on the medial surface of both legs, located just above the ankle bone and also the right anterior forearm located just above the wrist and on the same side as the palm of the hand, 3 electrodes per