Predicting Behavior From Actions in the Past: Repeated Decision Making or a Matter of Habit?

This paper summarizes research on determinants of repeated behaviors, and the decision processes underlying them. The present research focuses on travel mode choices as an example of such behaviors. It is proposed that when behavior is performed repeatedly and becomes habitual, it is guided by automated cognitive processes, rather than being preceded by elaborate decision processes (i.e., a decision based on attitudes and intentions). First, current attitude-behavior models are discussed, and the role of habit in these models is examined. Second, research is presented on the decision processes preceding travel mode choices. Based on the present theoretical and empirical overview, it is concluded that frequently performed behavior is often a matter of habit, thereby establishing a boundary condition for the applicability of attitude-behavior models. However, more systematic research is required to disentangle the role of habit in attitude-behavior models and to learn more about the cognitive processes underlying habitual behavior.     

Can the World Help Us in Fixing the Reference of Natural Kind Terms?

According to Putnam the reference of natural kind terms is fixed by the world, at least partly; whether two things belong to the same kind depends on whether they obey the same objective laws. We show that Putnam's criterion of substance identity only “works” if we read “objective laws” as “OBJECTIVE LAWS”. Moreover, at least some of the laws of some of the special sciences have to be included. But what we consider to be good special sciences and what not depends upon our values. Hence, “objective laws” cannot be read as “OBJECTIVE LAWS”. It follows that the reference of natural kind terms cannot be fixed by the world, not even partly. The final conclusion applies to a variety of realisms. This revised version was published online in August 2006 with corrections to the Cover Date.     

The Freedom-based Account of Solidarity and Basic Income

Real-libertarianism, as it is expressed in Philippe Van Parijs' recent monograph Real Freedom for All is characteristically committed to both self-ownership and 'solidarity’ with the infirm or handicapped. In this article it is argued that the conception of (real) freedom that is used to endorse self-ownership is inconsistent with the conception of (social) freedom or opportunity that is used to justify transfer payments to those with no or low earning capacity. The problem turns around the question whether one's freedom consists in the access one has to a share of the social product or in the measure of economic self-sufficiency one enjoys. Accordingly the role of private property in external resources as a condition for freedom is unclear: is it the basis of people's capacity for self-determination or is it the basis of people's bargaining power? Van Parijs' commitment to self-ownership suggests the former, his commitment to solidarity suggests the latter. A similar ambivalence is pointed out in his argument for a universal basic income, for which Real Freedom for All is so well-known.     

Robust canonical discriminant analysis

A method for robust canonical discriminant analysis via two robust objective loss functions is discussed. These functions are useful to reduce the influence of outliers in the data. Majorization is used at several stages of the minimization procedure to obtain a monotonically convergent algorithm. An advantage of the proposed method is that it allows for optimal scaling of the variables. In a simulation study it is shown that under the presence of outliers the robust functions outperform the ordinary least squares function, both when the underlying structure is linear in the variables as when it is nonlinear. Furthermore, the method is illustrated with empirical data.The research of the first author was supported by the Netherlands Organization of Scientific Research (NWO grant 560-267-029).     

The role of analogy in the interpretation of novel compounds

It was investigated whether the on-line interpretative processing of novel nominal compounds is affected by analogous lexicalized compounds. In Experiment 1, novel compounds were presented as nonwords in a lexical decision task. Constituent nouns of novel compounds were of high or low productivity as measured by the number of lexicalized compounds of which they were part. Effects of productivity and of compound interpretability on decision latencies were found to be additive, suggesting that the activated lexicalized compounds do not contribute to the interpretation of novel compounds. In Experiment 2, a semantic priming paradigm was used in a lexical decision task. Lexicalized compounds were presented as targets and novel compounds as primes. Second nouns of lexicalized and novel compounds were identical and first nouns of the two types of compounds were semantically related. Target compounds differed in frequency. Equal priming effects were obtained for high- and low-frequency target compounds, indicating that novel compounds do not activate more strongly the most similar lexicalized compound. The role of analogous interpretative processing is considered in the context of alternative models for the interpretation of novel compounds.     

Discrimination of 3-D shape and 3-D curvature from motion in active vision

We examined the ability of human observers to discriminate between different 3-D quadratic surfaces defined by motion, and with head position fed back to the stimulus to provide an up-to-date dynamical perspective view. We tested whether 3-D shape or 3-D curvature would affect discrimination performance. It appeared that discrimination of 3-D quadratic shape clearly depended on shape but not on the amount of curvature. Even when the amount of curvature was randomized, subjects’ performance was not altered. On the other hand, the discrimination of 3-D curvature clearly depended linearly on curvature with Weber fractions of 20% on the average and, to a small degree, on 3-D shape. The experiment shows that observers can easily separate 3-D shape and 3-D curvature, and that Koenderink’s shape index and curvedness provide a convenient way to specify shape. These results warn us against using just any arbitrary 3-D shape in 3-D shape perception tasks and indicate, for example, that emphasizing 3-D shape in computer displays by exaggerating curvature does not have any effect.     

A new axiomatization of portfolio theory

An axiomatization proposed by Coombs 1974 is shown to be insufficient for the representation of gambles in a risk × expected value space as described by Portfolio Theory. A new axiom system is given which is necessary and sufficient for this representation, and which implies the old axiomatization.