A dynamic context model of interactive behavior

A dynamic context model of interactive behavior was developed to explain results from two experiments that tested the effects of interaction costs on encoding strategies, cognitive representations, and response selection processes in a decision-making and a judgment task. The model assumes that the dynamic context defined by the mixes of internal and external representations and processes are sensitive to the interaction cost imposed by the task environment. The model predicts that changes in the dynamic context may lead to systematic biases in cognitive representations and processes that eventually influence decision-making and judgment outcomes. Consistent with the predictions by the model, results from the experiments showed that as interaction costs increased, encoding strategies and cognitive representations shifted from perception-based to memory-based. Memory-based comparisons of the stimuli enhanced the similarity and dominance effects, and led to stronger systematic biases in response outcomes in a choice task. However, in a judgment task, memory-based representations enhanced only the dominance effects. Results suggested that systematic response biases in the dominance context were caused by biases in the cognitive representations of the stimuli, but response biases in the similarity context were caused by biases in the comparison process induced by the choice task. Results suggest that changes in interaction costs not only change whether information was assessed from the external world or from memory but also introduce systematic biases in the cognitive representation of the information, which act as biased inputs to the subsequent decision-making and judgment processes. Results are consistent with the idea of interactive cognition, which proposes that representations and processes are contingent on the dynamic context defined by the information flow between the external task environment and internal cognition.     

An introduction to Bayesian model selection for evaluating informative hypotheses

Most researchers have specific expectations concerning their research questions. These may be derived from theory, empirical evidence, or both. Yet despite these expectations, most investigators still use null hypothesis testing to evaluate their data, that is, when analysing their data they ignore the expectations they have. In the present article, Bayesian model selection is presented as a means to evaluate the expectations researchers have, that is, to evaluate so called informative hypotheses. Although the methodology to do this has been described in previous articles, these are rather technical and havemainly been published in statistical journals. The main objective of thepresent article is to provide a basic introduction to the evaluation of informative hypotheses using Bayesian model selection. Moreover, what is new in comparison to previous publications on this topic is that we provide guidelines on how to interpret the results. Bayesian evaluation of informative hypotheses is illustrated using an example concerning psychosocial functioning and the interplay between personality and support from family.     

An Examination of Rapid Positioning Movements with Spatiotemporal Constraints

Unidirectional positioning movements with spatiotemporal-constraints were examined as a test of impulse-timing theory (Schmidt, 1976; 1980; Wallace, 1981). Movements were examined at the kinematic, kinetic, and neuromuscular levels in three experiments. In the first experiment, displacement was held constant while five different movement times were examined. Both amplitudes and durations of the EMG and the kinetic variables were related to movement time. The results generally support the impulse-timing model. In the second experiment, movements were performed to a target at each of four distances in a constant movement time. EMG and force amplitudes and, unexpectedly, accelerative-force duration were modulated to achieve changes in displacement when movement time was constant. In the third experiment, movement time and displacement were simultaneously varied resulting in four conditions with equal average velocities. The results of this experiment were not as clear and exhibited individual differences. EMG duration did not always vary with changes in movement time. The results of all three experiments could not be adequately accounted for by the impulse-timing model.     

The dark and the bright sides of proactive work behaviour and situational constraints: Longitudinal relationships with task conflicts

We investigated relationships of a job stressor (situational constraints) and specific proactive behaviours with change in task conflicts over time. We introduced two distinct types of proactive work behaviour (promotion-oriented initiative and prevention-oriented initiative) and examined their positive but also negative relationships with change in task conflicts. Study 1 supported the construct validity of promotion-oriented initiative and prevention-oriented initiative for 363 student assistants: Confirmatory factor analyses indicated that both types of proactive behaviour were distinct constructs and also distinct from active coping; patterns of correlations were similar to those of a prior concept of proactive behaviour. Study 2 was a longitudinal online survey with 197 employees over 3 weeks. Consistent with our hypotheses, situational constraints and promotion-oriented initiative predicted an increase in task conflicts, whereas prevention-oriented initiative predicted a decrease in task conflicts.     

Syntactical Constraints on Definitions

This essay considers arguments for and against syntactical constraints on the proper formalization of definitions, originally owing to Alfred Tarski. It discusses and refutes an application of the constraints generalized to include a prohibition against not only object‐place but also predicate‐place variables in higher‐order logic in a criticism of a recent effort to define the concept of heterologicality in a strengthened derivation of Grelling's paradox within type theory requirements. If the objections were correct, they would offer a more general moral for the proper formal definition of terms in philosophical logic. The criticism nevertheless seems mistaken both in the substance and specific application with respect to legitimate synctactical constraints on definitions of key concepts in the case of Grelling's paradox. As such, the critique provides no justification for overturning previous conclusions concerning the possibility of resurrecting a type‐observant version of Grelling's heterologicality paradox.     

Motor Programming as a Function of Constraints on Movement Initiation

Three experiments are reported that test the hypothesis that under certain conditions programming time is a function of the directional accuracy demand of a response, directional accuracy being quantified by the minimal angle subtended at the point of movement initiation by the circular targets within the response. Subjects in three simple reaction time experiments were required to tap a single target or a series of circular targets as rapidly as possible with a hand-held stylus. Experiments 1 and 3 showed that the subtended angle (SA) of a response can have a more powerful effect on programming time, as indexed by reaction time and premotor time, than the number of movement parts in the response. The results of Experiment 2 revealed that the locus of the directional accuracy effect was SA and not target size or movement distance. In all three experiments, response SA was a better predictor of programming time than was number of movement parts, target size, movement distance, movement time, and average movement velocity. The findings support the notion that constraints placed upon movement initiation by the directional accuracy demand of the task can play an important role in determining the length of the programming process.     

Reasonable Impartiality and Priority for Compatriots. A Criticism of Liberal Nationalism’s Main flaws

Distinguishing between reasonable partiality and reasonable impartiality makes a difference in resolving the serious clashes between priority for compatriots versus cosmopolitan global duties. Defenders of a priority for compatriots have to acknowledge two strong moral constraints: states have to fulfil all their special, domestic and trans-domestic duties, and associative duties are limited by distributive constraints resulting from the moral duty to fight poverty and gross global inequalities. In the recent global context, I see four main problems for liberal-nationalist defenders of priority for compatriots: (i) Reasonable particularists often forget that associative duties for compatriots compete with many sub-national and trans-domestic associative duties. (ii) They tend to forget that associative national duties compete with other, strong special (contractual, reparative) obligations regarding not only citizens and residents inside nation-states but also trans-domestic obligations across state borders. (iii) They do not properly discuss the problem of unallocated duties in addressing global poverty and insecurity. (iv) The design of supra-national and global mediating institutions, and the crafting of policies to remedy the misallocation of duties and to coordinate the required state activities is an urgent task neglected by liberal nationalists. In the recent context, reasonable partialitys bias towards partiality is most unwelcome and morally dubious. Reasonable impartialitys bias towards cosmopolitanism helps to stimulate a drastic shift in obligations and stimulates productive trans-national institutional design.     

Aspectual Constraints in the Mental Lexicon

This study addresses the question of whether constraints on aspectual semantics play a role in lexical processing. Two universal cognitive constraints are identified: states cannot be delimited and telic predicates cannot be further telicized. The study investigates how these are obeyed in the productive process of perfective preverb and stem combination in Bulgarian. An off-line task ascertains that Bulgarian native speakers have a default semantic interpretation for the preverbs under investigation. A visual lexical decision task shows clear legality effects in nonwords composed of existing preverbs and stems, thereby supporting decompositional approaches. It is argued that, after the process of morpheme search, there must be a process of checking for combinatory felicity of the morphemes activated in the lexical access.     

Component analysis with different sets of constraints on different dimensions

Many of the classical multivariate data analysis and multidimensional scaling techniques call for approximations by lower dimensional configurations. A model is proposed, in which different sets of linear constraints are imposed on different dimensions in component analysis and classical multidimensional scaling frameworks. A simple, efficient, and monotonically convergent algorithm is presented for fitting the model to the data by least squares. The basic algorithm is extended to cover across-dimension constraints imposed in addition to the dimensionwise constraints, and to the case of a symmetric data matrix. Examples are given to demonstrate the use of the method.The work reported in this paper has been supported by the Natural Sciences and Engineering Research Council of Canada, grant number A6394, and by the McGill-IBM Cooperative Grant, both granted to the first author. The research of H. A. L. Kiers has been made possible by a fellowship of the Royal Netherlands Academy of Arts and Sciences. We thank Michael Hunter for his helpful comments on earlier drafts of this paper.     

Use of public information when foraging: effects of time available to sample foods

It has been proposed that use of socially acquired information by animals should increase as the time available for individual resource sampling decreases. We gave Norway rat “observers” either 2 or 5 h day^–1 to sample four foods. Three of these foods were relatively palatable, but protein-poor; the fourth was relatively unpalatable, but protein-rich. We found that observer rats that for 2 h day^–1 both sampled foods and interacted with demonstrators eating only the protein-rich food ate more of the protein-rich food than did observers that sampled for 2 h day^–1 but had no opportunity to interact with demonstrators. On the other hand, observer rats that could sample foods for 5 h day^–1 ate equal amounts of protein-rich food whether they interacted with a demonstrator fed protein-rich food or not. Subsequent analyses showed that the time available to observers to sample foods, rather than the opportunity to interact with demonstrators determined whether such interaction influenced observers’ food choices. The results are consistent with the hypothesis that animals increase their use of public information in response to temporal constraints on opportunities for resource sampling. Received: 22 December 1998 / Accepted after revision: 27 February 1999