Tilmann Betsch

Multiple-Reason Decision Making Based on Automatic Processing

It has been repeatedly shown that in decisions under time constraints, individuals predominantly use noncompensatory strategies rather than complex compensatory ones. We argue that these findings might be due not to limitations of cognitive capacity but instead to limitations of information search imposed by the commonly used experimental tool Mouselab (Payne et al., 1988). We tested this assumption in three experiments. In the first experiment, information was openly presented, whereas in the second experiment the standard Mouselab program was used under different time limits. The results indicate that individuals are able to compute weighted additive decision strategies extremely quickly if information search is not restricted by the experimental procedure. In a third experiment, these results were replicated using more complex decision tasks, and the major alternative explanations that individuals use more complex heuristics or merely encode the constellation of cues were ruled out. In sum, the findings challenge the fundaments of bounded rationality and highlight the importance of automatic processes in decision making.

Modeling Option and Strategy Choices with Connectionist Networks: Towards an Integrative Model of Automatic and Deliberate Decision Making

We claim that understanding human decisions requires that both automatic and deliberate processes be considered. First, we sketch the qualitative differences between two hypothetical processing systems, an automatic and a deliberate system. Second, we show the potential that connectionism offers for modeling processes of decision making and discuss some empirical evidence. Specifically, we posit that the integration of information and the application of a selection rule are governed by the automatic system. The deliberate system is assumed to be responsible for information search, inferences and the modification of the network that the automatic processes act on. Third, we critically evaluate the multiple-strategy approach to decision making. We introduce the basic assumption of an integrative approach stating that individuals apply an all-purpose rule for decisions but use different strategies for information search. Fourth, we develop a connectionist framework that explains the interaction between automatic and deliberate processes and is able to account for choices both at the option and at the strategy level.

The Influence of Vaccine-critical Websites on Perceiving Vaccination Risks

This large-scale Internet-experiment tests whether vaccine-critical pages raise perceptions of the riskiness of vaccinations and alter vaccination intentions. We manipulated the information environment (vaccine-critical website, control, both) and the focus of search (on vaccination risks, omission risks, no focus). Our analyses reveal that accessing vaccine-critical websites for five to 10 minutes increases the perception of risk of vaccinating and decreases the perception of risk of omitting vaccinations as well as the intentions to vaccinate. In line with the ‘risk-as-feelings’ approach, the affect elicited by the vaccine-critical websites was positively related to changes in risk perception.

I Like it but I Don’t Know Why: A Value-Account Approach to Implicit Attitude Formation

The authors suggest a theory that predicts how summary evaluations about targets are implicitly formed and stored in memory and under which conditions they are used in attitude judgment. First, it is assumed that the mere encoding of value-charged stimuli is a sufficient condition to initiate implicit online formation of summary evaluations. Second, the authors claim that this process is summative. Accordingly, the intensities of the positive or negative responses evoked by the stimuli in the organism are thought to be accumulated and stored in a unitary memory structure. This hypothetical structure is called value account. Third, it is assumed that a value account is more easily accessible in memory than are concrete traces of past experiences. Therefore, attitude judgments should rely on value accounts, especially if cognitive capacities are constrained (e.g., due to time pressure). Three experiments that provide converging evidence for the value-account approach are reported.

A sampling approach to biases in conditional probability judgments: beyond base rate neglect and statistical format.

Conditional probability judgments of rare events are often inflated when some meaningful relation exists between the condition and the low-baserate event. While traditional explanations assume that human judgments are generally insensitive to statistical baserates, more recent evidence shows much better performance when the problems are presented in natural frequency (as opposed to probability) formats and when the conditions refer to natural categories. The theory advanced here suggests a different explanation. Rather than postulating an a priori advantage of natural formats or categories, we emphasize sampling decisions as a key to understanding biased probability judgments. Experiment 1 shows that the seeming advantage of frequencies over probabilities is confined to conditions in which probabilities are scaled with reference to unequal subsamples. In Experiment 2, an active information search paradigm is employed that always provides a natural frequency format. When sampling by the predictor condition, the conditional probability to be estimated, p(criterion/ predictor), is conserved in the samples and the resulting judgments are quite accurate. However, when sampling by the criterion, the low-baserate event is strongly overrepresented in the samples. This sampling bias is even stronger than the resulting judgment bias. In general, judgments reflect the statistics of the actually acquired samples rather accurately, but judges do not understand the logical constraints imposed by their own sampling. This interpretation is corroborated in Experiment 3, where judges can freely choose between predictor sampling and criterion sampling, and in Experiment 4 using direct evaluations of the appropriateness of different sampling procedures.

The Influence of Narrative v. Statistical Information on Perceiving Vaccination Risks

Background. Health-related information found on the Internet is increasing and impacts patient decision making, e.g. regarding vaccination decisions. In addition to statistical information (e.g. incidence rates of vaccine adverse events), narrative information is also widely available such as postings on online bulletin boards. Previous research has shown that narrative information can impact treatment decisions, even when statistical information is presented concurrently. Objectives. As the determinants of this effect are largely unknown, we will vary features of the narratives to identify mechanisms through which narratives impact risk judgments. Methods. An online bulletin board setting provided participants with statistical information and authentic narratives about the occurrence and nonoccurrence of adverse events. Experiment 1 followed a single factorial design with 1, 2, or 4 narratives out of 10 reporting adverse events. Experiment 2 implemented a 2 (statistical risk 20% vs. 40%) × 2 (2/10 vs. 4/10 narratives reporting adverse events) × 2 (high vs. low richness) × 2 (high vs. low emotionality) between-subjects design. Dependent variables were perceived risk of side-effects and vaccination intentions. Results. Experiment 1 shows an inverse relation between the number of narratives reporting adverse-events and vaccination intentions, which was mediated by the perceived risk of vaccinating. Experiment 2 showed a stronger influence of the number of narratives than of the statistical risk information. High (vs. low) emotional narratives had a greater impact on the perceived risk, while richness had no effect. Implications. The number of narratives influences risk judgments can potentially override statistical information about risk.

Intuition in Judgment and Decision Making: Extensive Thinking Without Effort

We claim that intuition is capable of quickly processing multiple pieces of information without noticeable cognitive effort. We advocate a component view stating that intuitive processes in judgment and decision making are responsible for information integration and output formation (e.g., preference, choice), whereas analytic thinking mainly guides input formation such as search, generation, and change of information. We present empirical evidence corroborating this notion and show that integration of information and preference formation works without cognitive control and is unconstrained by the amount of encoded information and cognitive capacity. We discuss the implications of our findings for the bounded rationality perspective and the multiple strategy approach to judgment and decision making. Finally we outline a connectionist framework for integrating intuitive and analytic thought processes.

Behavioral routines in decision making: the effects of novelty in task presentation and time pressure on routine maintenance and deviation

This article examines the role of behavioral routines in decision making. In order to induce routines, participants were confronted with recurrent route decisions in a computer-controlled trucking game, which allows for manipulation of routine acquisition and strength. During the final round of the game, time pressure and novelty in task presentation were varied as between-factors. It was hypothesized that time pressure would increase the likelihood of routine maintenance and novelty would increase the likelihood of deviation. Besides individual choices, response latencies and self-reports were additionally assessed to measure the amount of deliberation during decision making. Results show that time pressure strongly increased the probability of routine maintenance, even though the situation indicated the inadequacy of the routine. In contrast, novelty in task presentation provoked routine deviation and increased deliberation, as evident from response latencies and self-reports. Copyright

Do People Make Decisions Under Risk Based on Ignorance? An Empirical Test of the Priority Heuristic Against Cumulative Prospect Theory

Brandstatter, Gigerenzer and Hertwig (2006) put forward the priority heuristic (PH) as a fast and frugal heuristic for decisions under risk. According to the PH, individuals do not make trade-offs between gains and probabilities, as proposed by expected utility models such as cumulative prospect theory (CPT), but use information in a non-compensatory manner and ignore information. We conducted three studies to test the PH empirically by analyzing individual choice patterns, decision times and information search parameters in diagnostic decision tasks. Results on all three dependent variables conflict with the predictions of the PH and can be better explained by the CPT. The predictive accuracy of the PH was high for decision tasks in which the predic-tions align with the predictions of the CPT but very low for decision tasks in which this was not the case. The findings indicate that earlier results supporting the PH might have been caused by the selection of decision tasks that were not diagnostic for the PH as compared to CPT.

Coherence shifts in probabilistic inference tasks

The fast-and-frugal heuristics approach to probabilistic inference assumes that individuals often employ simple heuristics to integrate cue information that commonly function in a non-reciprocal fashion. Specifically, the subjective validity of a certain cue remains stable during the application of a heuristic and is not changed by the presence or absence of another cue. The parallel-constraint-satisfaction model, in contrast, predicts that information is processed in a reciprocal fashion. Specifically, it assumes that subjective cue validities interactively af-fect each other and are modified to coherently support the favored choice. Corresponding to the model’s simulation, we predicted the direction of such coherence shifts.Cue validities were measured before, after (Exp. 1) and during judgment (Exp. 2 & 3). Coherence shifts were found in environments involving real-world cue knowledge (weather forecasts) and in a domain for which the application of fast-and-frugal heuristics has been demonstrated (city-size tasks). The results indicate that subjective cue validities are not fixed parameters, but that they are interactively changed to form coherent representations of the task.