Learning mechanisms in pathological gambling

Project1 consists of three experiments (all involve a sequence of 25 single games on a modified slot machine). The dependent variables will all be the same for every experiment (heart rate and heart rate variability, self-reported mood and gambling urge). In the first experiment, 100 subjects will be randomized to one of two different conditions (one win of 500 NOK at game no. 3 in the sequence or a win of 500 NOK at game no. 22). In the second experiment, 100 subjects will be randomized to one of two dif ferent experimental conditions (a 32% near-miss condition or a 0% near-miss condition. In the third experiment, 100 subjects will be randomized to one of two different experimental conditions (one condition where the slot machine emits game-related light and auditory stimuli and one condition where the slot machine does not emit any light or auditory stimuli). In project2, 30 pathological gamblers and 30 non-pathological controls will participate in 3 basic learning experiments. In the first experiment 15 1000 Hz tones followed by one dishabituation trial with a 1500Hz tone will be presented. The second study consists of a habituation phase with five presentations of the to be CS. Half of the subjects (both the pathological gambling and the non-patholog ical gambling group) will randomly be assigned to two conditions. In one condition a 1000Hz tone will act as the CS+ (i.e. CS is always followed by the UCS). During this condition, the 1200Hz tone will serve as the CS- (i.e. never followed by the UCS). Fo r the second condition this is reversed. The third phase of the paradigm consists of an extinction phase. In this phase 15 CS+ and 15 CS- are presented randomly without the UCS. White noise (90 db) will operate as the unconditioned stimulus (UCS). Experim ent3 is identical to experiment2 but here 15 sensitization control stimuli (2000 Hz) will be presented additionally. All the dependent variables comprise measures of cardiovascular and electrodermal responses.