Different Types Of Criminals' Decision-making Defects In The Iowa Gambling Task

Affective decision-making is an individual ability to make choice under risk and uncertainty, it help us make a benifical decision-making for ourselves and for other people and the whole society. Affective decision-making dysfunction will cause serious personal or social consequences, such as: drugs, crimes and so on. Criminal behavior is a result of criminal decision-making, they make their own decision such as whether to use drug, whether to use violence to solve problems in real life. Criminal decision-making involves a variety of uncertainties, such as:crime preparedness, environmental conditions of criminal behavior, criminal loss, the proceeds of crime, which require decision-maker to integrate emotional and logical decision-making results. Criminals are to be fettered and thrown into prison because they have made wrong decisions. Are there any defects of criminal's affective decision-making function? If so, which mental dysfunction causes their decision-making defects? This study focuses on these two issues.The Iowa Gambling Task (IGT) developed by Bechara has been widely used to assess decision behavior under uncertainty. A modified version of Iowa Gambling Task, IGT, was used in two experiment to explore these issuses.7 types,212 male offenders in prison were recruited in experiment 1, and there decision-making founction were measured by IGT. In order to verify the results of experiment 1,8 types, other 222 male offenders'decision-making function were measured first, then the expectancy utility learning model (EUL) and prospect utility learning model (PUL) were used to analysis the mental dysfunction under decision-making defects. The EUL model contains three parameters:loss aversion (w), learning update rate (A), choice consistency (c) and PUL model contains four parameters:loss aversion (λ), shape of functionα), learning update rate (A), and choice consistency (c).In experiment 1, all of the 7 types criminal show decision-making defects. They all prefer deck 2 which belongs to disadvantage decks and there was no significant differences between eight types of criminal's decision-making performance, but their performance were significant poor than the control group. They did not change their selection strategy along with the choices like normal control. In experiment 2, all of the 8 types crimianl show smilar choice behavior. The goodness of fittest of PUL model was better than other three models, so PUL model was used to analysis mental dsyfunction of criminals. Compare to the control group, violent offenders and mafia-like criminals' loss aversion parameter and function shape parameter were significant lower. Their learning update rate was significant higher than control and other types of criminals. And their choice consistency was significant higher than other types of participant. Drug abstainers, drug criminal, thief and robbery were lower in the loss aversion parameter; there choice consistency was very high. Economic criminal's choice consistency was very low which indicated that they were more cautious than other types of criminal. And the last, sex offender's choice consistency was very high which indicated that there behavioral reversal function was defected.These results from two experiment shows that IGT is a sensitive task, in which the characteristics of each type subject can be reflected in the decision-making process. Both EUL and PUL can be used to analyse mental function of decision-maker in IGT, but the goodness of fittest of PUL is better. Differential types of criminal prefer deck 2 shows that all of them have decision-making defects. Violent offenders and mafia-like criminals didn't sensitive to reward and punishment; they were fast discount the utility of past events, their behavioral reversal function was defected. Drug abstainers, drug criminal, thief and robbery were insensitive to punishment, their behavioral reversal function was defected. Economic criminals were more cautious than other types of criminal. And the last, sex offenders'behavioral reversal function was defected.In conclusion, the present research suggested that different types of criminal have similar decision-making functional deficits, but the mental dysfunction cuause these deficits were different.