Suchergebnisse

Two experiments are reported, which test the hypothesis that acute stress leads to suboptimal decisions under uncertainty (outcomes known but not their probabilities), due to a stressor caused bias toward the preference for positive feedbacks. The published literature suggests that acute stress leads to suboptimal decision-making, but only for those subjects who show a strong cortisol response. The stress hormone cortisol biases the reward system towards a preference for positive feedbacks, while ignoring or neglecting negative feedbacks. A critical review of the literature revealed, that this hypothesis has a questionable data basis. Additionally, there is not a single study using a direct cortical index of feedback processing. The Feedback Related Negativity (FRN), a component of the event-related potential, is measured as a direct index of optimal feedback processing. Both experiments used the Social Evaluated Cold Pressure Test (SECPT) as a stress paradigm. The Balloon Analogue Risk Task (BART) was decision-making procedure in experiment 1, whereas experiment 2 used the Iowa Gambling Task (IGT). The FRN was measured contingent on positive and negative feedbacks during the decision tasks. Three groups were analyzed: two SECPT groups (cortisol high vs cortisol low responders), and a control group performing the Social Evaluated Warm Pressure Test. Though all manipulation checks regarding the behavioral and biological results of the acute stressor and the BART or the IGT could be validated empirically, both experiments revealed no influence of the acute stressor on decision making under uncertainty or on feedback processing, as indexed by the FRN. It is concluded that acute stress has no negative influence on decision-making under uncertainty. Possible objections to this conclusion are discussed in the final sections of this thesis, before developing a basic paradigm, which might guide future research in this field.

Two experiments are reported, which test the hypothesis that acute stress leads to suboptimal decisions under uncertainty (outcomes known but not their probabilities), due to a stressor caused bias toward the preference for positive feedbacks. The published literature suggests that acute stress leads to suboptimal decision-making, but only for those subjects who show a strong cortisol response. The stress hormone cortisol biases the reward system towards a preference for positive feedbacks, while ignoring or neglecting negative feedbacks. A critical review of the literature revealed, that this hypothesis has a questionable data basis. Additionally, there is not a single study using a direct cortical index of feedback processing. The Feedback Related Negativity (FRN), a component of the event-related potential, is measured as a direct index of optimal feedback processing. Both experiments used the Social Evaluated Cold Pressure Test (SECPT) as a stress paradigm. The Balloon Analogue Risk Task (BART) was decision-making procedure in experiment 1, whereas experiment 2 used the Iowa Gambling Task (IGT). The FRN was measured contingent on positive and negative feedbacks during the decision tasks. Three groups were analyzed: two SECPT groups (cortisol high vs cortisol low responders), and a control group performing the Social Evaluated Warm Pressure Test. Though all manipulation checks regarding the behavioral and biological results of the acute stressor and the BART or the IGT could be validated empirically, both experiments revealed no influence of the acute stressor on decision making under uncertainty or on feedback processing, as indexed by the FRN. It is concluded that acute stress has no negative influence on decision-making under uncertainty. Possible objections to this conclusion are discussed in the final sections of this thesis, before developing a basic paradigm, which might guide future research in this field.

Attention and the closely related concept of salience play an important role in the complex process of human decision-making. In 2012, Bordalo et al. (2012a) proposed a theory on human decision-making that is based on salience. They suggest that salience differences within a decision problem may explain many decision biases. Concerning decisions under risk, Bordalo and colleagues developed a formula to calculate salience differences that are shaped by bottom-up processes. These salience differences have been experimentally investigated. Reaction times in a dot-probe task served as indicator of attentional biases. Data revealed a significant salience effect after a lottery exposure duration of 150 ms. This supports the salience concept proposed by Bordalo et al. (2012a) and suggests an early attentional orienting towards salient payoffs. In order to further differentiate attentional processes involved in the salience effect EEG has been recorded. Different ERP-components may indicate attentional biases at different stages of attentional processing and give a hint at more detailed reasons behind the salience effect. All investigated components, namely, P1, N1, P3a and P3b, showed no significant salience differences. Part III presents a further experiment that was devoted to nudges. These interventions often work by altering the salience within a decision problem or by directing the attention to the decision task itself. Since these interventions influence decisions at least partly on an unconscious level, nudges are subject to criticism. The experiment aimed at investigating the effect of transparent information accompanying the nudges on their efficacy. In line with previous research adding information on the nudge itself, on its purpose and the combination of both had no significant effect on the efficacy of the nudge, even though this additional information again alters salience ratios within the decision problem.

Attention and the closely related concept of salience play an important role in the complex process of human decision-making. In 2012, Bordalo et al. (2012a) proposed a theory on human decision-making that is based on salience. They suggest that salience differences within a decision problem may explain many decision biases. Concerning decisions under risk, Bordalo and colleagues developed a formula to calculate salience differences that are shaped by bottom-up processes. These salience differences have been experimentally investigated. Reaction times in a dot-probe task served as indicator of attentional biases. Data revealed a significant salience effect after a lottery exposure duration of 150 ms. This supports the salience concept proposed by Bordalo et al. (2012a) and suggests an early attentional orienting towards salient payoffs. In order to further differentiate attentional processes involved in the salience effect EEG has been recorded. Different ERP-components may indicate attentional biases at different stages of attentional processing and give a hint at more detailed reasons behind the salience effect. All investigated components, namely, P1, N1, P3a and P3b, showed no significant salience differences. Part III presents a further experiment that was devoted to nudges. These interventions often work by altering the salience within a decision problem or by directing the attention to the decision task itself. Since these interventions influence decisions at least partly on an unconscious level, nudges are subject to criticism. The experiment aimed at investigating the effect of transparent information accompanying the nudges on their efficacy. In line with previous research adding information on the nudge itself, on its purpose and the combination of both had no significant effect on the efficacy of the nudge, even though this additional information again alters salience ratios within the decision problem.