How To Engage With Experimental Practices? Moderate Versus Radical Constructivism

A central question in constructivist studies of science is how the analyst should deal with the material objects handled by scientific practitioners in laboratories. Representatives of ‘radical constructivism’ such as Knorr-Cetina and Latour have gone furthest in exploring the role of these ‘non-humans’ but have also maneuvered themselves in untenable positions due to a fatal conflation of different meanings of the term ‘construction’. The epistemological and ontological commitments of ‘moderate constructivism’ especially of the Strong Program defended by Barnes and Bloor, are more suitable for dealing with the task at hand. While radical constructivists treat the domains of nature and human society as largely coterminous, an alternative ontology stresses that natural reality is never fully absorbed into the world of culture but only interacts with the latter at localizable interfaces such as practices and artifacts. This perspective promises a more relaxed relationship with current forms of scientific realism. This revised version was published online in August 2006 with corrections to the Cover Date.     

Preferences for leadership in social dilemmas: Public good dilemmas versus common resource dilemmas

It has been argued that a structural solution to social dilemmas is to install a leader, but here we consider the possibility that group members will oppose giving up their decisional freedom. Previous studies have shown that feedback indicating collective failure results in a stronger preference for the leadership option. We argue that preferences for the leadership option depend not only on the feedback group members receive, but also on the type of dilemma they are facing. The results of our experiment, in which we manipulated dilemma type as well as feedback, corroborate our reasoning. The distribution of initial property in public good and common resource dilemmas helps to explain these findings.     

Risky visuomotor choices during rapid reaching in childhood

Many everyday actions are implicit gambles because imprecisions in our visuomotor systems place probabilities on our success or failure. Choosing optimal action strategies involves weighting the costs and gains of potential outcomes by their corresponding probabilities, and requires stable representations of one's own imprecisions. How this ability is acquired during development in childhood when visuomotor skills change drastically is unknown. In a rewarded rapid reaching task, 6‐ to 11‐year‐old children followed ‘risk‐seeking’ strategies leading to overly high point‐loss. Adults' performance, in contrast, was close to optimal. Children's errors were not explained by distorted estimates of value or probability, but may reflect different action selection criteria or immature integration of value and probability information while planning movements. These findings provide a starting point for understanding children's risk‐taking in everyday visuomotor situations when suboptimal choices can be dangerous. Moreover, children's risky visuomotor decisions mirror those reported for non‐motor gambles, raising the possibility that common processes underlie development across decision‐making domains.     

Public good provision under environmental and social uncertainty

Social dilemmas face people with various kinds of uncertainty. To extend earlier research on environmental uncertainty in resource dilemmas (i.e. uncertainty about the resource size), the present experiment examines the effects of Environmental Uncertainty (low, high uncertainty about the provision point) and Social Uncertainty (low, high uncertainty about others' cooperation) in a public goods dilemma. In line with Social Comparison Theory, it was predicted and found that Environmental Uncertainty decreases cooperation only under High Social Uncertainty, but not under Low Social Uncertainty. The detrimental effects of Environmental Uncertainty can be counteracted by uncertainty reducing information on the provision point and/or on others' contributions as well. © 1998 John Wiley & Sons, Ltd.     

Habit,information acquisition,and the process of making travel mode choices

Three studies examined the role of habit on information acquisition concerning travel mode choices. On the basis of Triandis' (1980) model of attitude–behaviour relations it was expected that habit strength attenuates the elaborateness of choice processes. The studies focused on different phases in the choice process, namely the appreciation of situational cues and appreciation of choice option information. In line with expectations, it was found that, compared to weak habit participants, those who had a strong habit towards choosing a particular travel mode acquired less information and gave evidence of less elaborate choice strategies. It was attempted to break effects of habit by manipulating either accountability demands or level of attention. Although accountability demands raised the level of information acquisition, no interactions with habit were found. Enhanced attention to the choice process initially did override habit effects in a series of choice trials. However, in spite of this manipulation, chronic habit effects emerged during later trials. The results demonstrate the profound effects that habit may have on the appreciation of information about choice situations and choice options. ©1997 John Wiley & Sons, Ltd.     

To plan or not to plan? Goal achievement or interrupting the performance of mundane behaviors

The present experiment investigated cognitive and behavioral effects of planning (i.e. forming implementation intentions) on goal pursuit during the performance of mundane behaviors. Participants received the goal to collect a coupon halfway the hall from the lab to the cafeteria. Later, they were also given the task to go from the lab to the cafeteria. Thus participants had to attain a new goal by interrupting a mundane behavior. Some participants enriched their goal with implementation intentions, others did not. Results showed that participants who formed implementation intentions were more effective in goal pursuit than the control group. Importantly, the data suggest that the effects of planning on goal completion are mediated by a heightened mental accessibility of environmental cues related to the goal completion task. Copyright © 1999 John Wiley & Sons, Ltd.     

An alternating least squares method for the weighted approximation of a symmetric matrix

Bailey and Gower examined the least squares approximationC to a symmetric matrixB, when the squared discrepancies for diagonal elements receive specific nonunit weights. They focussed on mathematical properties of the optimalC, in constrained and unconstrained cases, rather than on how to obtainC for any givenB. In the present paper a computational solution is given for the case whereC is constrained to be positive semidefinite and of a fixed rankr or less. The solution is based on weakly constrained linear regression analysis.The authors are obliged to John C. Gower for stimulating this research.