Further attempts to clarify the importance of category variability for categorisation

The issue of how category variability affects classification of novel instances is an important one for assessing theories of categorisation, yet previous research cannot provide a compelling conclusion. In five experiments we reexamine some of the factors thought to affect participant performance. In Experiments 1 and 2, participants almost always classified the test item as belonging to the high variability category. By contrast, in Experiment 3 we employed an alternative experimental paradigm, where the difference in variability of the two categories was less salient. In that case, participants tended to classify a test item as belonging to the low variability category. Two additional experiments (4 and 5) explored in detail the differences between Experiments 1, 2 on the one hand, and 3 on the other. Some insight into the underlying psychological processes can be provided by computational models of categorisation, and we focus on the continuous version of Anderson's (1991) Rational Model, which has not been explored before in this context. The model predicts that test instances exactly halfway between the prototypes of two categories should be classified into the more variable category, consistent with the bulk of empirical findings. We also provided a comparison with a slightly reduced version of the Generalised Context Model (GCM) to show that its predictions are consistent with those from the Rational Model, for our stimulus sets.     

The impact of using forced decision-making strategies on post-decisional confidence

The impact of motivational and cognitive factors on post-decisional confidence (PDC) level was tested in two experiments. In the first experiment, subjects were first identified as having an intuitive preference toward using either a compensatory or a noncompensatory decision strategy and later on were forced to use either a compatible or a non-compatible strategy. PDC level decreased after using a noncompensatory strategy, and the decrease was higher when it was a noncompatible strategy. In a second experiment, subjects received feedback about their preferred strategy but were not later forced to use any specific strategy. Most subjects continued to utilize their preferred strategy and PDC level was not changed. Overall, intuitive PDC was not found to be sensitive to differences between compensatory and noncompensatory strategies. The result suggested that PDC is a function of an internal cost-benefit analysis which includes both cognitive and motivational factors.     

Rank disagreement: A comparison of multi-criteria methodologies

A number of multi-criteria decision support techniques have emerged in recent years that use varying computational approaches to arrive at the most desirable solution and thereby ‘recommend’ a course of action. Decision makers who use the results of this analytic work should be assured that the computational schemes used by their supporting analysts or decision support software produce the appropriate solutions. We conducted a series of simulation experiments that compared the top-ranked options resulting from the computational algorithms that support Multi-Attribute Value Theory (MAVT) and three methods that are reported in the literature that allow rank reversals, the change in rank order of two options when an unrelated option is added or deleted from the analysis: the Analytical Hierarchy Process (AHP), Percentaging and the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). We also included a Fuzzy algorithm proposed by Yager to gauge its consistency with the other algorithms, even though it is not subject to rank reversals. These experiments demonstrated that the MAVT and AHP techniques, when provided with the same decision outcome data, very often identify the same alternative as ‘best’. The other techniques are noticeably less consistent with MAVT, the Fuzzy algorithm being the least consistent. The situations under which the most frequent and significant differences occurred were dependent upon the method. The results of our experiments indicate that other issues (e.g. the processes used for problem structuring and the elicitation of value weights) are likely to be of greater significance to problem outcome (based on our experience) than the choice between the computational algorithms of MAVT and AHP. The results cause us to be concerned about the use of the other methods.     

The assistant referees’ activity in refereeing elite football: Preoccupations when not judging offside

ObjectiveThe purpose of this research was to study the preoccupations assistant referees had to participate in decision making about duels during football games.DesignResearch adopted a phenomenological framework to investigate the assistant referees’ lived experiences in order to understand their activity when they judged duels in match.MethodThis study investigated six professional football matches. Researchers conducted a participatory observation of the refereeing team before each match. Twelve self-confrontation interviews with each assistant referee of each match were conducted in order to make him/her describing his/her unfolding lived experience during the match.ResultsIn case of players’ duels, the perception of contextual cues enabled the assistants to appraise the occurring of a decision process with the central referee. For the assistants, the occurring of a decision process with the central referee meant his priority to intervene in the adjudication of duels, while the absence of decision process with the central referee meant for the assistants the possibility to intervene. The assistants adjusted their way of judging duels to how the central referee judged the previous ones.ConclusionsThe participation of assistants in decision making about duels depends on their preoccupations concerning the central referee’s priority. The way assistants perceive the central referee’s contextual judgment shapes the way they adjudicate duels. A latent intention to coordinate with the central referee, in relation with their collaborative tasks, is embedded in their preoccupations. Our results are a platform to develop further research about the referees’ collective activity.     

A one-boundary drift-diffusion model for time to collision estimation in a simple driving task

ABSTRACT

Driving is a complex everyday task. Every year a huge number of driving accidents around the world causes serious physical and mental injuries and deaths. The correct estimation of the remaining time to reach the other vehicles on the road, known as time to collision (TTC), is an important factor to avoid accidents. In this study, we aimed to use a drift-diffusion model (DDM) to better understand the participants’ estimation of TTC in two driving experiments. Both experiments were the same, except that in one of them participants were asked to finish the experiment as fast as they could, while in the other experiment there was no time constraint. DDM fitted the data from all participants well in both experiments according to the chi-square goodness of fit criterion. Also, results showed that time pressure increases subjects’ estimated TTC, the rate of accumulation of sensory information and the response threshold.     

The use of partial information on weights in multicriteria decision problems

This paper addresses multicriteria decision problems in which only partial information is given in the decision-making process. We generalize existing results about preference relations induced by nonnegative inverse matrices, allowing linear relations on weights with upper and lower bounds. In addition we develop conditions for additional information that preserve the special properties studied and show how to incorporate the new information to the model. © 1998 John Wiley & Sons, Ltd.     

Decision by sampling

We present a theory of decision by sampling (DbS) in which, in contrast with traditional models, there are no underlying psychoeconomic scales. Instead, we assume that an attribute's subjective value is constructed from a series of binary, ordinal comparisons to a sample of attribute values drawn from memory and is its rank within the sample. We assume that the sample reflects both the immediate distribution of attribute values from the current decision's context and also the background, real-world distribution of attribute values. DbS accounts for concave utility functions; losses looming larger than gains; hyperbolic temporal discounting; and the overestimation of small probabilities and the underestimation of large probabilities.     

Individualism, Communitarianism and Consensus

There is a contemporary conflict between individualistic andcommunitarian conceptions of rationality. Robert Goodin describes it asa conflict between an enlightenment individualistic conception of a``sovereign artificer'' and ``a socially unencumbered self'' ascontrasted with the communitarian conception of a ``socially embeddedself'' whose identity is formed by his or her community. Should wejustify and explain rationality individualistically or socially? This isa false dilemma when consensus is reached by a model articulated byKeith Lehrer and Carl Wagner. According to this model, the consensusresults from the positive weights individuals give to others and use tocontinually average and, thus, aggregate their allocations. Aggregationconverges toward a consensus in which the social preference and theindividual preferences become identical. The truth of communitarianismis to be found in the aggregate and the truth of individualism in theaggregation. The original conflict dissolves in rational consensus.     

The propensity theory: a decision-theoretic restatement

Probability theory is important because of its relevance for decision making, which also means: its relevance for the single case. The propensity theory of objective probability, which addresses the single case, is subject to two problems: Humphreys’ problem of inverse probabilities and the problem of the reference class. The paper solves both problems by restating the propensity theory using (an objectivist version of) Pearl’s approach to causality and probability, and by applying a decision-theoretic perspective. Contrary to a widely held view, decision making on the basis of given propensities can proceed without a subjective-probability supplement to propensities.