Dorien Bangma

30 | CHAPTER 2 Participants are asked to indicate for each statement whether they in general apply to them. All items are rated on a four-point scale, which ranges from 1 ( strongly disagree ) to 4 ( strongly agree ). However, some items are formulated contra-indicatively and the score of these items need to be mirrored (i.e., 4 ( strongly disagree ) to 1 ( strongly agree )). Sum scores are calculated for the affective, cognitive and situational component. Since the combination of the two models is still experimental, the situational component is not part of the total score of the IBQ, which represent the overall tendency to buy on impulsive (i.e., the sum of the affective and cognitive component). Higher scores are indicative for a stronger tendency to buy on impulse. The IBQ is a self-report questionnaire and the administration time of the IBQ is approximately 5-10 minutes. IGT: Iowa gambling task The Iowa Gambling Task (IGT) is a widely used test and was developed to assess real-life decision-making (Bechara et al., 1994). The IGT is frequently used as a measure of risk-taking and/or gambling behavior, however, the IGT seems to primarily assess emotional decision- making in healthy individuals (Buelow & Suhr, 2009). Emotional decision-making in the context of the IGT can be described as an unconscious urge or feeling based on previous experience and emotional stage which has an influence on decision-making (Bechara et al., 1997; Buelow & Suhr, 2009). A computerized, Dutch version of the IGT has been used (Figure 2.4; Grasman & Wagenmakers, 2005). In this task, participants have to choose cards from four decks of virtual cards. Each deck is associated with certain gains and losses. The number of cards in each deck is unlimited. The goal of the task is to gain as much money as possible and to minimize losing money. Participants play with hypothetical money, but are asked to consider this money as real. Two decks are considered disadvantageous and two decks are considered advantageous. The disadvantageous decks 1 and 2 (the two left-sided decks) lead to relatively high gains (i.e., €100) but also to relatively high losses (i.e., between €100 and €1250; Figure 2.4a). Decks 3 and 4, the advantageous decks, result in relatively low gains (i.e., €50) but also in relatively low losses (i.e., between €50 and €250; Figure 2.4b). Only minimal instructions are given to the participants. Besides the instructions on the computer (Figure 2.4c), participants receive more detailed instructions by the examiner. Participants are beforehand not informed about the advantageous and disadvantageous decks and the rules of winning and losing. They therefore have to learn from trial and error which decisions are most advantageous. During the task, participants receive feedback about the amount gained or lost and the total amount of money they have. Furthermore, the gains and losses can be tracked by a green and by a red bar that increase when money is gained or lost, respectively (Figure 2.4). In total, participants have to choose a card 100 times, however, the participants are not informed about the number of cards they have to choose beforehand. A total netscore, i.e., the number of times a participant chose the advantageous decks minus the number of times the participant chose the disadvantageous decks, over 100 trials is calculated. Furthermore, the netscore can be divided in five parts of 20 trials to assess the effect of feedback and risky decision-making (Brand et al., 2006). The administration time of the IGT is approximately 15-20 minutes.