Dual conception of risk in the Iowa Gambling Task: effects of sleep deprivation and test-retest gap

Varsha Singh

doi:10.3389/fpsyg.2013.00628

Abstract

Risk in the Iowa Gambling Task (IGT) is often understood in terms of intertemporal choices, i.e., preference for immediate outcomes in favor of delayed outcomes is considered risky decision making. According to behavioral economics, healthy decision makers are expected to refrain from choosing the short-sighted immediate gain because, over time (10 trials of the IGT), the immediate gains result in a long term loss (net loss). Instead decision makers are expected to maximize their gains by choosing options that, over time (10 trials), result in delayed or long term gains (net gain). However, task choices are sometimes made on the basis of the frequency of reward and punishment such that frequent rewards/infrequent punishments are favored over infrequent rewards/frequent punishments. The presence of these two attributes (intertemporality and frequency of reward) in IGT decision making may correspond to the emotion-cognition dichotomy and reflect a dual conception of risk. Decision making on the basis of the two attributes was tested under two conditions: delay in retest and sleep deprivation. An interaction between sleep deprivation and time delay was expected to attenuate the difference between the two attributes. Participants were 40 male university students. Analysis of the effects of IGT attribute type (intertemporal vs. frequency of reinforcement), sleep deprivation (sleep deprivation vs. no sleep deprivation), and test-retest gap (short vs. long delay) showed a significant within-subjects effect of IGT attribute type thus confirming the difference between the two attributes. Sleep deprivation had no effect on the attributes, but test-retest gap and the three-way interaction between attribute type, test-retest gap, and sleep deprivation were significantly different. Post-hoc tests revealed that sleep deprivation and short test-retest gap attenuated the difference between the two attributes. Furthermore, the results showed an expected trend of increase in intertemporal decision making at retest suggesting that intertemporal decision making benefited from repeated task exposure. The present findings add to understanding of the emotion-cognition dichotomy. Further, they show an important time-dependent effect of a universally experienced constraint (sleep deprivation) on decision making. It is concluded that risky decision making in the IGT is contingent on the attribute under consideration and is affected by factors such as time elapsed and constraint experienced before the retest.

Highlights

The Iowa Gambling Task (IGT; Bechara et al, 1994) is used to test a hypothesis about emotion and decision making called the somatic marker hypothesis (SMH; Damasio, 1994)
The results showed a difference between the total net scores calculated on the basis of two different conceptualizations of risk in IGT—one based on the intertemporal nature of reward and punishment and the other based on preference for a specific frequency of immediate reward and punishment
The test-retest gap interacted with attribute type suggesting that risk taking is differentially susceptible to time delay between the two exposures to the IGT

Summary

Introduction

The Iowa Gambling Task (IGT; Bechara et al, 1994) is used to test a hypothesis about emotion and decision making called the somatic marker hypothesis (SMH; Damasio, 1994). Unbeknown to the decision maker, decks A and B have high immediate rewards (100 points per card-pick) with 50% of cards drawn from deck A giving a loss of 35–100 points and 10% of cards drawn from deck B giving a loss of 1250 points, such that 10 cards drawn from decks A and B result in a net loss of 250 points. Decks C and D have small immediate rewards (50 points per card-pick) with 50% of cards drawn from deck C giving a loss of 25–75 points and 10% of cards drawn from deck D giving a loss of 250 points, such that 10 cards drawn from decks C and D result in a net gain of 250 points. The four decks differ in two ways: (a) net outcome across time (i.e., inter temporal attribute) by which decks A and B could be considered risky in the long term, whereas decks C and D could be considered safe in the long term, and (b) frequency of immediate reward and punishment notwithstanding net or long-term outcomes www.frontiersin.org

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