The Processes of Scientific Discovery: The Strategy of Experimentation

Hans Krebs' discovery, in 1932, of the urea cycle was a major event in biochemistry. This article describes a program, KEKADA, which models the heuristics Hans Krebs used in this discovery. KEKADA reacts to surprises, formulates explanations, and carries out experiments in the same manner as the evidence in the form of laboratory notebooks and interviews indicates Hans Krebs did. Furthermore, we answer a number of questions about the nature of the heuristics used by Krebs, in particular: How domain-specific are the heuristics? To what extent are they idiosyncratic to Krebs? To what extent do they represent general strategies of problem-solving search? The relative generality of KEKADA allows us to view the control structure of KEKADA and its domain-independent heuristics as a model of scientific experimentation that should apply over a broad domain.     

A manifesto for the new MCDA era

The following manifesto has been prepared by five prominent workers in the field of MCDA. We are currently preparing a special issue on the issues that they raise (see Call for Papers on p. 128). We invite you to contribute to the debate in that issue, either in the form of a paper or a letter to the Editor.     

Memory and planning processes in solutions to well-structured problems

Although many studies in the problem-solving literature have considered the factors that might determine the strategies that are employed to solve well-structured problems, these have typically focused upon variants of means-end analysis. In general, such models imply that strategies unfold in a temporally forward direction, that problem solvers typically restrict forward-planning activities to just one or two moves ahead of the current problem state, and that one important heuristic is the avoidance of previous moves. Although studies have demonstrated the importance of such anti-looping heuristics, few have systematically explored the possibility that problem solvers may also plan retrospectively in order to try and assess whether a move might take them back to a state that they have previously visited. Those models of problem solving that promote the role of an anti-looping heuristic have assumed that the ability to use such a heuristic is based upon memory for previous states, but other interpretations are possible. In this paper several studies are reported that attempt systematically to explore participants' attempts to recognize previously visited problem solving states. The findings suggest that there is a systematic relationship between the success of this process, the time taken to make this judgement, and distance from the current state. It is also demonstrated that estimations about where future positions are likely to occur are symmetrical to estimations about past positions. It is suggested that this provides evidence that problem solvers engage in retrospective planning processes in order to try and avoid previous moves, and that this strategy may not be based straightforwardly upon their ability to remember previous problem states.     

The Darlington Family Assessment Sytem: clinical guidelines for practitioners

The Darlington Family Assessment System (DFAS) consists of a framework of widely accepted concepts, a semi-structured family interview and rating scale, and a detailed account of how to use the system in clinical practice. The model views health issues within a family life-cycle (developmental) framework. It assesses problems at four systemic levels: the child perspective, the parental perspective, the parent-child perspective, and the whole family perspective. The semi-structured interview is designed to see how family members perceive problems and to map out other possible problems, and is a useful basic training tool. Empirical work suggests that the framework of key concepts and the rating scale offer a powerful method for describing and differentiating families. There is evidence that the model is useful as a training method for health professionals undergoing basic training. Detailed clinical guidelines have also been developed, to show how the model can be applied in practice. The advantage of the model is that it can be used with a variety of therapeutic approaches, and to inform choices about which interventions are likely to be successful or not.     

The paradox(es) of pitying and fearing fictions

The acknowledged paradox in our emotional response to fictional characters and events is that the very beliefs required by a cognitive account of the emotions are excluded by knowledge that the context is fictional. Various proposed solutions have failed to reconcile cognitivism with respect to the emotions with the facts of that response. Those offered include denying cognitivism by excluding the belief on the emotions, denying genuine emotional response in these contexts, or advocating either fictional realism or irrationalism in such response. By specifically examining pity and fear this paper tries to reconcile genuine emotional response to fictional characters and events with a unified cognitive account of the emotions by arguing that instead of excluding belief the existential condition on the beliefs in an emotion can be lifted by the invitation to imagine. At the same time it shows that the richness of that response need not be denied and throws some light on further related paradoxes (for instance by indicating why not all emotions are rationally possible in fictive contexts and that although we can pity fictions we cannot rationally fear them). Then by explaining why, unlike in ordinary contexts we do not act on our emotions in fictive ones, it differentiates the reasons for passivity in fictional and in historical circumstances.