The primary objective of this study was to examine the extent to which increased experience in working in a group would affect group versus individual problem solving. The duration and intensity of group involvement for subjects (over 30 hr) was extensive. In addition, the reward system provided a clear and direct tie between individual or group performance and a significant outcome (i.e., course grades). The decision-making task had a great deal in common with many of the aspects of group decision making in organizations. Results were overwhelmingly in favor of group decision making across time, given this type of task. The percentage by which the group performance score was higher (or lower) than the group's best member was called the group added value (G>W). In addition, a synergy ratio was developed in an attempt to measure how much a group added over their best member's contributions. Best members rarely repeated as the top scorer and became less important to group success as the groups gained experience. The results call into question much of the previous group decision-making research and strongly support the value of group-consensus decision making both in task forces and ongoing organizational groups.

In the context of a discussion of time symmetry in the quantum mechanical measurement process, Aharonov et al. (1964) derived an expression concerning probabilities for the outcomes of measurements conducted on systems which have been pre- and postselected on the basis of both preceding and succeeding measurements. Recent literature has claimed that a resulting “time-symmetrized” interpretation of quantum mechanics has significant implications for some basic issues, such as contextuality and determinateness, in elementary, nonrelativistic quantum mechanics. Bub and Brown (1986) have shown that under the standard interpretation of the aforementioned expression, these claims employ ensembles which are not well defined. It is argued here that under a counterfactual interpretation of the expression, these claims may be understood as employing well-defined ensembles; it is shown, however, that such an interpretation cannot be reconciled with the standard interpretation of quantum mechanics.

Philosophers like Duhem and Cartwright have argued that there is a tension between laws' abilities to explain and to represent. Abstract laws exemplify the first quality, phenomenological laws the second. This view has both metaphysical and methodological aspects: the world is too complex to be represented by simple theories; supplementing simple theories to make them represent reality blocks their confirmation. We argue that both aspects are incompatible with recent developments in nonlinear dynamics. Confirmation procedures and modelling strategies in nonlinear dynamics show that there are simple, abstract theories that can be confirmed without encountering the problems pointed to by Cartwright. 1 Introduction 2 Confirmability and explanatory power 3 Phenomenological and other theories 4 Simple theories of messy systems 5 Confirmation in nonlinear dynamics 6 Explanatory power in nonlinear dynamics 1 Conclusion

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A certain order or stability of nature has often been seen as a necessary presupposition of many of our scientific practices, in particular of our use of information gained in one kind of circumstance to explain or predict what happens in quite different situations. John Maynard Keynes and, more recently, Nancy Cartwright have argued that these practices commit us to the existence of stable ‘atoms’ or ‘natures’ or ‘tendencies.’ The phenomena we observe in nature are, on this view, the result of superimposing the invariable, context-independent effects of all the different tendencies involved.