Research has shown that people perceive themselves as less biased than others, and as better than average in many favorable characteristics. We suggest that these types of biased perceptions regarding intentions and behavior of others may directly affect people’s decisions. In the current research we focus on possible influences in the context of helping behavior. In four experiments we found that, people believe that others, compared to themselves, are less inclined to help and cooperate, are less aware of the number of bystanders and more influenced by the “proportion dominance” bias and by the “identifiable victim effect.” We demonstrate that these perceptions are naïve and unrealistic by showing that decisions from both self and others’ perspectives are equally biased. Finally, we show how the perspective from which a decision is made (self vs. others) may affect private as well as public decisions in ways that might not be in the best interest of the decision maker and the public.

Three experiments demonstrate how the processing of negations is contingent on the evaluation context in which the negative information is presented. In addition, the strategy used to process the negations induced different affective reactions toward the stimuli, leading to inconsistency of preference. Participants were presented with stimuli described by either stating the presence of positive features (explicitly positive alternative) or negating the presence of negative features (non-negative alternative). Alternatives were presented for either joint (JE) or separate evaluation (SE). Experiment 1 showed that the non-negative stimuli were judged less attractive than the positive ones in JE but not in SE. Experiment 2 revealed that the non-negative stimuli induced a less clear and less positive feeling when they were paired with explicitly positive stimuli rather than evaluated separately. Non-negative options were also found less easy to judge than the positive ones in JE but not in SE. Finally, Experiment 3 showed that people process negations using two different models depending on the evaluation mode. Through a memory task, we found that in JE people process the non-negative attributes as negations of negative features, whereas in SE they directly process the non-negative attributes as positive features.

Measuring reaction times to number comparisons is thought to reveal a processing stage in elementary numerical cognition linked to internal, imprecise representations of number magnitudes. These intuitive representations of the mental number line have been demonstrated across species and human development but have been little explored in decision making. This paper develops and tests hypotheses about the influence of such evolutionarily ancient, intuitive numbers on human decisions. We demonstrate that individuals with more precise mental-number-line representations are higher in numeracy (number skills) consistent with previous research with children. Individuals with more precise representations (compared to those with less precise representations) also were more likely to choose larger, later amounts over smaller, immediate amounts, particularly with a larger proportional difference between the two monetary outcomes. In addition, they were more likely to choose an option with a larger proportional but smaller absolute difference compared to those with less precise representations. These results are consistent with intuitive number representations underlying: a) perceived differences between numbers, b) the extent to which proportional differences are weighed in decisions, and, ultimately, c) the valuation of decision options. Human decision processes involving numbers important to health and financial matters may be rooted in elementary, biological processes shared with other species.

The purpose of the present study was to investigate the effect of perceived time pressure on a learning-based task called the Iowa Gambling Task (IGT). One hundred and sixty-three participants were randomly assigned to one of two groups. The experimental group was informed that the time allotted was typically insufficient to learn and successfully complete the task. The control group was informed that the time allotted was typically sufficient to learn and successfully complete the task. Both groups completed the IGT and performance was recorded. The major finding was that participants who were advised that the amount of time allotted was typically insufficient to complete the task performed significantly worse than those who were advised that time was typically sufficient to complete the task.

In two studies on mobile phone purchase decisions, we investigated consumers’ decision strategies with a newly developed process tracing tool called InterActive Process Tracing (IAPT). This tool is a combination of several process tracing techniques (Active Information Search, Mouselab, and retrospective verbal protocol). After repeatedly choosing one of four mobile phones, participants formalized their strategy so that it could be used to make choices for them. The choices made by the identified strategies correctly predicted the observed choices in 73% (Experiment 1) and 67% (Experiment 2) of the cases. Moreover, in Experiment 2 we directly compared Mouselab and eye tracking with respect to their impact on information search and strategy description. We found only minor differences between these two methods. We conclude that IAPT is a useful research tool to identify choice strategies, and that using eye tracking technology did not increase its validity beyond that gained with Mouselab.

Despite vigorous research on risk communication, little is known about the social forces that drive these choices. Erev, Wallsten, & Neal (1991) showed that forecasters learn to select verbal or numerical probability estimates as a function of which mode yields on average the larger group payoffs. We extend the result by investigating the effect of group size on the speed with which forecasters converge on the better communication mode. On the basis of social facilitation theory we hypothesized that small groups induce less arousal and anxiety among their members than do large groups when performing new tasks, and therefore that forecasters in small groups will learn the better communication mode more quickly. This result obtained in Experiment 1, which compared groups of size 3 to groups of size 5 or 6. To test whether social loafing rather than social facilitation was mediating the effects, Experiment 2 compared social to personal feedback holding group size constant at 3 members. Learning was faster in the personal feedback condition, suggesting that social facilitation rather than loafing underlay the results.

Professional judges in traffic courts sentence many hundreds of offenders per year. Using 639 case files from archives, we compared the Matching Heuristic (MH) to compensatory, weighing algorithms (WM). We modeled and cross validated the models on different subsets of the data, and took several other methodological precautions such as allowing each model to select the optimal number of variables and ordering and weighing the variables in accordance to different logics. We did not reproduce the finding by Dhami (2003), who found the MH to be superior to a compensatory algorithm in modeling bail-granting decisions. These simulations brought out the inner logic of the two family of models, showing what combination of parameters works best. It remains remarkable that using only a fraction of the variables and combining them non-compensatorily, MH obtained nearly as good a fit as the weighing method.

A case study review of a formal decision analysis involving a 10 year old girl. She had just faced the death of a close adult friend, and had become filled with uncertainty and emotion while facing the decision as to whether or not to attend his funeral. The study demonstrates that formal analysis can provide the sensitivity and caring basis for such decision making, thus counteracting some of the criticisms of decision analysis.