Abstract: Internet addiction, defined as a maladaptive use of the Internet, is estimated to occur in 8–13% of college students (Chou, Condron, & Belland, 2005). It has become a serious mental health issue worldwide because addicts are impaired in various behavioral aspects including social interactions and academic performance (Morahan-Martin & Schumacher, 2000; Scherer, 1997; Young, 1998). Some researchers consider Internet addiction as a kind of behavioral addiction. However, there are few experimental studies on the cognitive functions of Internet addicts and limited data are available to compare Internet addicts with other addictive behaviors, such as drug abuse and pathological gambling. In the present study, we examined internet addicts’ function of decision making. Two groups of participants, 42 Internet addicts (18~22 years old, 32 male, M = 19.79, SD = 1.14) and 42 controls (18~22 years old, 26 male, M = 19.71, SD = 1.13), were compared on the cognitive function and impulsivity by using a Chinese computerized versions of the IGT and Sensation Seeking Scale (SSS). In the IGT, subjects had to choose between four decks of cards. Unknown to the subjects, two piles offered larger short-term gains that are offset by greater risks of heavy losses, and hence were disadvantageous in the long run. The other two piles offered smaller short-term gains and a lower risk of loss that result in long-term maximization of the monetary payoff. The results of the present study showed that (1) compared with controls, sensation seeking of internet addicts was higher significantly, and internet addicts showed significantly higher scores on subscales of thrill and adventure seeking, disinhibition and boredom susceptibility, and they selected significantly less net decks in the Iowa Gambling Task. Furthermore, Internet addicts made no progress in selecting strategy along with the time course of the decision making. (2) reaction patterns for pure win-cards were consistent between Internet addicts and controls, however, the former still preferred to choose high win-cards in spite of potential high punishment whereas the latter tended to transform the direction of card selection after getting corresponding feedback to avoid potentially high risks. (3) Net scores of the IGT were not correlated with SSS. These results showed some similarities between Internet addiction and other addictive behaviors such as drug abuse and pathological gambling. The findings from the Iowa Gambling Task indicated that Internet addicts have deficits in decision making function, which are characterized by an immediate win-priority selection pattern and tolerance to high risk.

Key words: decision making, internet addiction, personality, Iowa Gambling Task, impulsivity