van den Bos Ruud, Houx Bart B, Spruijt Berry M
Ethology and Welfare, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 2, NL-3584 CM Utrecht, The Netherlands.
Biol Psychol. 2006 Feb;71(2):155-61. doi: 10.1016/j.biopsycho.2005.05.003. Epub 2005 Aug 10.
In the Iowa Gambling Task, participants have to develop a long-term profitable monetary scenario in a situation of uncertainty and a conflict between the chance of encountering an immediate large reward (100 US dollars) in two long-term loosing decks (A and B; -250 US dollars per 10 cards) and the chance of encountering an immediate small reward (50 US dollars) in two long-term winning decks (C and D; +250 US dollars per 10 cards). The ratio of the immediate rewards in decks A/B and C/D is thus 2:1. Here, we manipulated these differences in reward magnitude between the advantageous (C/D) and disadvantageous (A/B) decks, while keeping the net gains and losses per 10 cards the same, to assess the impact of the conflict between immediate and distant pay-off on choice behaviour. Participants selected less cards from disadvantageous decks and won more money when the reward magnitude difference was decreased, A/B:C/D=1:1, while they selected more cards from disadvantageous decks and lost more money when reward magnitude differences were increased, A/B:C/D=4:1 and 6:1. This study shows that the outcome in the Iowa Gambling Task is sensitive to differences between the magnitude of immediate rewards in the advantageous and disadvantageous decks.
在爱荷华赌博任务中，参与者必须在不确定的情况下，以及在两种长期输钱的牌组（A和B；每10张牌输250美元）中获得即时大额奖励（100美元）的机会与在两种长期赢钱的牌组（C和D；每10张牌赢250美元）中获得即时小额奖励（50美元）的机会之间的冲突下，制定出一个长期盈利的金钱方案。因此，牌组A/B和C/D中即时奖励的比例为2:1。在这里，我们在保持每10张牌的净收益和损失相同的情况下，操纵了有利（C/D）和不利（A/B）牌组之间奖励幅度的这些差异，以评估即时和远期回报之间的冲突对选择行为的影响。当奖励幅度差异减小，A/B:C/D = 1:1时，参与者从不利牌组中选择的牌较少且赢得更多的钱；而当奖励幅度差异增大，A/B:C/D = 4:1和6:1时，他们从不利牌组中选择的牌较多且输的钱更多。这项研究表明，爱荷华赌博任务的结果对有利和不利牌组中即时奖励幅度的差异很敏感。
