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The Iowa Gambling Task was developed by Bechara et al. (IGT, 1994) in order to study the decision-making deficits found in patients with ventromedial prefrontal cortex (vmPFC) lesions.

Despite these patients having intact cognitive and memory abilities, they tend to display problems when considering the consequences of their actions and when learning from their mistakes. The IGT was designed to mimic real-life decision making in an experimental setting.

Participants select cards from four available decks that differ in the amount of fictitious monetary reward and punishment they are associated with. They are told to choose cards that maximise their long-term outcomes, but are unaware that the reward and punishment outcomes are fixed. Decks A and B contain risky cards that have high immediate rewards but even higher occasional losses, and decks C and D contain safer cards that have smaller immediate rewards but also smaller losses.

During the first few deck selections, when participants are making decisions under ambiguity and do not know the rules associated with each deck, it is assumed that decisions are made based on “gut feelings”, or unconscious emotions (Bechara, 2005; Bechara et al, 1997; Brand et al, 2007). However as the task goes on and participants have more explicit understanding about the risks and benefits associated with each deck, their decision making is more likely to be based on a conscious level, with deliberation of risk and informed judgement occurring (Brand et al, 2007). In this way, the IGT can provide information about how people make risky decisions and the level of risk they accept in order to obtain a reward.

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Although Decks A and B are equivalent in their overall total loss, Deck A is often perceived as more disadvantageous than Deck B (Bechara et al, 1994). Prospect Theory (Kahneman &

Tversky, 1979) explains this discrepancy by the differences in frequency of loss between the two decks. The punishment from Deck A is highly frequent and almost certain, whereas the punishment from Deck B occurs less frequently and is therefore less probable. Prospect Theory suggests that given the choice between a sure loss versus a possible loss – even though the possible loss will be of higher magnitude – people tend to prefer the less probable punishment and thus choose from Deck B. Although Deck B is a disadvantageous deck Bechara et al.

(1994) noted that some individuals continue to choose from it, particularly those who are sensation seekers and have a high tolerance for risk. A similar pattern is often seen in choices from Decks C and D. Although both are equivalent in terms of overall total gain, most people prefer Deck D. According to prospect theory this is because punishments are less probable from this deck, occurring less frequently than from Deck C. Bechara et al. (1994) suggested that individuals highly sensitive to punishment may tend to avoid Deck C, as although it is an advantageous deck, punishments from this deck are highly frequent in comparison to Deck D.

Success on the IGT can be achieved when participants sacrifice the decks offering them high immediate rewards and instead choose those that offer smaller gains but minimise the risk of long-term loss. The foundation for using the IGT to test the decision making capacity of vmPFC patients is based on the assumption that healthy participants will choose this decision-making route, basing their choices on long-term outcomes and so choose the safe cards because they will see that the risky decks are associated with long-term negative outcomes and so will avoid them (Caroselli et al, 2006).

The assumption that healthy participants will learn to choose the safe decks is crucial to the validity of using the IGT to test vmPFC patients, however recent research has cast doubt over this assumption. For example, Caroselli et al. (2006) found that healthy participants often base their deck selection on the frequency of losses; preferring the decks that offer them infrequent

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losses (decks B and D), rather than basing their decision on the long-term outcome of the game i.e. choosing decks associated with smaller gains rather than risk larger losses by choosing decks with larger wins. This unexpected finding from the IGT is termed the Prominent Deck B Phenomenon and when Dunn et al. (2006) conducted a meta-analysis of IGT studies they found that many participants including normal, unaffected individuals displayed this preference for Deck B, a “disadvantageous” deck.

Lin et al. (2007) investigated this notion further, presenting participants with a two-stage simple version of the IGT in which participants first selected cards from an AACC format (which had a balanced gain-loss frequency of 5 gains and 5 losses per 10 trials) and then a BBDD format (which had a high-frequency gain and low-frequency loss of 9 gains and 1 loss per 10 trials).

This enabled the researchers to monitor participants’ preferences after the first 100 trials. Lin et al. (2007) found that even after 100 trials participants failed to develop a preference for the

“advantageous” deck D over the “disadvantageous” deck B, suggesting that healthy participants may not be driven by long-term outcomes but by other factors instead. The authors proposed that high-frequency gain may be the primary influence in participants’ preference for deck B, because as well as being associated with bigger monetary gains, the win: lose ratio within deck B assures participants that they are much more likely to win, and with a bigger amount, than if they choose from one of the other decks. It was concluded that preference for the high-frequency gain deck B indicates that a bad long term outcome does not mean that participants will end up choosing to avoid it, and thus they are not in fact considering the long term negative consequences of their decisions at all.

A meta-analysis conducted by Steingroever et al. (2013) who analysed the findings of various studies of the IGT involving healthy participants, concluded that healthy participants frequently showed idiosyncratic choice behaviour, and often preferred the decks that were associated with infrequent losses, as opposed to simply the decks that had a large punishment regardless of the frequency with which it appeared. Rivalan et al. (2009) investigated the relative disparity in

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healthy participants’ deck choices, by developing a rat version of the IGT that assessed for the first time the ongoing decision making process within a single session. The authors presented rats with various options, with the disadvantageous ones offering a larger immediate food reward but were followed up with longer unpredictable time-outs. They found that whilst the majority of rats worked out the favourable options rapidly, some systematically chose disadvantageously, regardless of task complexity; suggesting that poor decision making did not occur as a result of failing to learn the information needed to make an advantageous decision, but from a hypersensitivity to reward and higher risk taking.

Similarly, Franken and Muris (2005) investigated whether individual differences in personality would predict performance on the IGT on a small sample of college students. They found that whilst impulsivity did not predict IGT performance, there was a relationship between sensitivity to reward and sensitivity to punishment on participants’ overall IGT performance. More recently Buelow and Suhr (2013) considered the relationship between state mood, personality characteristics and deck selections on the IGT. They found that whilst mood had little effect on deck selections, those high in sensation seeking and impulsivity made more Deck B selections and fewer Deck D selections; and BAS-Drive i.e. the persistent pursuit of desired goals, was also associated with greater Deck B and fewer Deck D selections.

The present study provides further investigation into the relationship between reward sensitivity, punishment sensitivity and risk taking behaviour on the IGT (Bechara et al, 1994). It has already been shown that some healthy participants choose deck B more often than the other decks, suggesting that some people do not base their decisions on long-term outcomes, but rather display a preference for cards that offer high immediate gains and relatively infrequent losses (Lin et al, 2007). In addition, studies such as those conducted by Franken and Muris (2005) and Buelow and Suhr (2013) have found a relationship between individuals’ reward sensitivity, punishment sensitivity and the number of cards chosen from specific decks on the IGT. Whilst these studies do appear to support the idea that reward sensitivity may underpin the

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risky decision making of some individuals, there has yet to be any consideration of potential gender differences in sensitivity to reward and risk-taking on the IGT. As young males tend to drive more riskily than females, and are at a higher risk of collision, it is especially important to uncover what may underpin their risk-taking behaviour. If reward sensitivity does underpin risky behaviour we would expect to see young males scoring high on this measure because young males are those most likely to engage in high risk driving. On this basis it is expected that reward sensitivity will motivate young males to accept more risk on the IGT when attempting to win rewards and so they will consistently choose more cards from the risky Deck B throughout the task.

We are interested in looking at the relationship between reward sensitivity, punishment sensitivity and risky decision making because the findings have the potential to direct future road safety initiatives. As seen in chapter two current road safety campaigns tend to be oriented around punishments and focus on attempting to educate young people about the negative consequences of risky driving. However it may be that some young people, particularly young males, make choices that reflect a particular sensitivity to reward rather than punishment, and might display this decision making process in their IGT performance. If reward sensitivity does underpin males’ risk-taking behaviour then this might explain why males and females responded differently to the intervention in chapter two. This would also then have implications for the best way to advocate safer driving for young males; and using rewards as incentives, such as fuel vouchers or reduced insurance premiums, may prove more effective in promoting continued safe driving than a punishment-oriented approach.

Studies investigating the relationship between reward sensitivity and risk-taking on the IGT (e.g. Buelow & Suhr, 2013; Lin et al, 2007) have not considered potential gender or age differences. Therefore the next two studies investigated the relationship between risky behaviour and reward sensitivity for young males and females, and older males, using the Iowa Gambling Task (Bechara et al, 1994). Participants select cards from four decks that differ in the

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amount of fictitious monetary reward and punishment they offer. Selecting from Deck B is risky but those with a high tolerance for risk - in particular, males - may choose from it as rewards are high with only a possible chance of loss. Those who are sensitive to punishment may avoid Deck C as although it is not risky punishments are frequent.

Thus there were two hypotheses for the present study:

a) High BAS scoring males, from here on in referred to as 'sensitive to reward', would choose more cards from Deck B, i.e. make more risky choices, than low BAS scorers throughout the task.

b) High BIS scorers, from here on in referred to as 'sensitive to punishment', would choose fewer cards from Deck C, i.e. fewer risky choices, throughout the task than low BIS scorers.

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3.2 Study Two a: The Relationship between Reward Sensitivity and Risky