Odilo W. Huber

Active information search and complete information presentation in naturalistic risky decision tasks

Most experimental results in research on risky decisions have been obtained with lotteries. Choices between lotteries differ in many respects from natural risky decision tasks. Furthermore, the mode of information presentation in gambling experiments is very different from natural situations. In our experiment, 32 non-students made choices in two naturalistic risky decision tasks. The mode of information presentation was varied: Complete information presentation (as common in gambling experiments) vs. Method of Active Information Search (the subject gets a basic description of the task, and has to ask questions to receive additional information). In naturalistic tasks, probability was used less often than expected from classical decision theory, whereas the search for new alternatives, worst-case plans and control considerations were more relevant. The type of information presentation had a distinct effect. With Active Information Search, only a minority of subjects was interested in probabilities. Precise probabilities were used solely in the condition with Complete information presentation.

Detectability of the negative event: effect on the acceptance of pre- or post-event risk-defusing actions.

In risky decision situations, many decision makers search for risk-defusing operators (RDOs). An RDO is an action intended by the decision maker to be performed additionally to a specific alternative and is expected to decrease the risk. Pre-event RDOs (e.g., vaccination) have to be applied before a negative event (e.g., infection) occurs. Post-event RDOs do not need to be initiated before and unless the event happens (e.g., medical treatment). For the successful application of Post-event RDOs, the negative event must be detected in time. Two experiments investigated the effect of uncertainty in the detection of the negative event. In Experiment 1, only a small minority of subjects noted this uncertainty without a cue, and even with cue, only a minority actively searched for probability information. In Experiment 2, the probability for correctly detecting the negative event was varied. When detection was certain, most subjects chose the alternative with a Post-event RDO, whereas this percentage decreased significantly with decreasing probability of correct detection. Also, in the conditions with a more extreme negative outcome, less decision makers chose the alternative with the Post-event RDO.

Justification pressure in risky decision making: Search for risk defusing operators

Under justification pressure, the decision maker knows in advance that the decision has to be justified to somebody afterwards. The effect of justification pressure on the search for risk defusing operators (RDOs) and the role of RDOs in the justification texts were investigated. An RDO is an action intended by the decision maker to be performed in addition to an otherwise attractive alternative to decrease the risk. As predicted, in Experiment 1 participants (60 non-students) under justification pressure searched more RDOs. Additionally, in Experiment 2 (80 non-students) RDO search success was varied. Under justification pressure, persistence of RDO search was higher when no RDO could be detected. In the justification texts, the existence or non-existence of RDOs played a prominent role. Searching for RDOs supports people in their goal to make a good decision and in their attempt to convince the addressee of their justification that the decision was good.

Active Search for Probability Information and Recall Performance: Is Probability an Outstanding Element in the Mental Representation of Risky Decisions?

Recall performance of (1) actively searched information vs. information prestructured by the experimenter and (2) actively searched probability information vs. non-probability information in quasi-realistic risky decisions was investigated. 42 subjects decided in 2 scenarios each. Information presentation was varied within subjects by means of the Active Information Search method (O.Huber, Wider & O.W.Huber, 1997). After a frugal basic description of the scenario (prestructured information) subjects ask questions and receive answers until they subjectively have enough information to decide (active search). In only 55% of the tasks probability was searched. Recall was measured 48 hours afterwards as surprise task, showing (1) actively searched probability being on average better recalled than other actively searched information and (2) actively searched information being better recalled than prestructured information. It is argued that (1) actively searched information in general is of greater importance, because it matches the specific information needs of the decision maker during the construction of the mental representation and (2) the role of probability information in the mental representation differs between subjects and tasks. Actively searched risk control information is proposed as one reason for this difference. If risk control is expected to be successful, probability information is of limited value.

Impairments in an early stage of the decision-making process in patients with ventromedial prefrontal damage: preliminary results

Lesions of the ventromedial prefrontal cortex can result in a deficient decision-making behavior. So far, most experimental results in the neuropsychological decision-making research have been obtained with gambling tasks. Due to their high complexity, it is difficult to evaluate the underlying processes of the decision-making deficits. The aim of this study was to assess if patients with ventromedial prefrontal damage compared to patients with dorsolateral prefrontal damage and controls show a deficit in an early stage of the decision-making process. Nine patients with ventromedial prefrontal damage, three with dorsolateral prefrontal damage, and eleven healthy controls were tested with a newly developed decision task in which they had to search actively for the information they needed for their decisions. Our results show that patients with ventromedial prefrontal damage compared to the brain-lesioned dorsolateral prefrontal control group and healthy controls searched less for information with regard to risk defusing operators or consequences of their decisions indicating impairment already in the early stage of the decision-making process.