The conventional wisdom declares that evolution is not goal directed, that teleological considerations play no part in our understanding of evolutionary trends. Here I argue that, to the contrary, under a current view of teleology, field theory, most evolutionary trends would have to be considered goal directed to some degree. Further, this view is consistent with a modern scientific outlook, and more particularly with evolutionary theory today. Field theory argues that goal directedness is produced by higher-level fields (...) that direct entities contained within them to behave persistently and plastically, that is, returning them to a goal-directed trajectory following perturbations (persistence) and directing them to a goal-directed trajectory from a large range of alternative starting points (plasticity). The behavior of a bacterium climbing a chemical food gradient is persistent and plastic, with guidance provided by the external “food field,” the chemical gradient. Likewise, an evolutionary trend that is produced by natural selection is a lineage behaving persistently and plastically under the direction of its local ecology, an “ecological field.” Trends directed by selection-generated boundaries, thermodynamic gradients, and certain internal constraints, would also count as goal directed. In other words, most of the causes of evolutionary trends that have been proposed imply goal directedness. However, under field theory, not all trends are goal directed. Examples are discussed. Importantly, nothing in this view suggests that evolution is guided by intentionality, at least none at the level of animal intentionality. Finally, possible implications for our thinking about evolutionary directionality in the history of life are discussed. (shrink)

When people describe motion events, their path expressions are biased toward inclusion of goal paths (e.g., into the house) and omission of source paths (e.g., out of the house). In this paper, we explored whether this asymmetry has its origins in people’s non-linguistic representations of events. In three experiments, 4-year-old children and adults described or remembered manner of motion events that represented animate/intentional and physical events. The results suggest that the linguistic asymmetry between goals and sources is not fully (...) rooted in non-linguistic event representations: linguistic descriptions showed the goal bias for both kinds of events, whereas non-linguistic memory for events showed the goal bias only for events involving animate, goal-directed motion. The findings are discussed in terms of the mapping between non-linguistic representations of goals and sources in language, focusing on the role that linguistic principles play in producing a more absolute goal bias from more gradient non-linguistic representations of paths. (shrink)

The fields of machine learning (ML) and cognitive science have developed complementary approaches to computationally modeling human behavior. ML's primary concern is maximizing prediction accuracy; cognitive science's primary concern is explaining the underlying mechanisms. Cross-talk between these disciplines is limited, likely because the tasks and goals usually differ. The domain of e-learning and knowledge acquisition constitutes a fruitful intersection for the two fields’ methodologies to be integrated because accurately tracking learning and forgetting over time and predicting future performance based on (...) learning histories are central to developing effective, personalized learning tools. Here, we show how a state-of-the-art ML model can be enhanced by incorporating insights from a cognitive model of human memory. This was done by exploiting the predictive performance equation's (PPE) narrow but highly specialized domain knowledge with regard to the temporal dynamics of learning and forgetting. Specifically, the PPE was used to engineer timing-related input features for a gradient-boosted decision trees (GBDT) model. The resulting PPE-enhanced GBDT outperformed the default GBDT, especially under conditions in which limited data were available for training. Results suggest that integrating cognitive and ML models could be particularly productive if the available data are too high-dimensional to be explained by a cognitive model but not sufficiently large to effectively train a modern ML algorithm. Here, the cognitive model's insights pertaining to only one aspect of the data were enough to jump-start the ML model's ability to make predictions—a finding that holds promise for future explorations. (shrink)

The fields of machine learning (ML) and cognitive science have developed complementary approaches to computationally modeling human behavior. ML's primary concern is maximizing prediction accuracy; cognitive science's primary concern is explaining the underlying mechanisms. Cross-talk between these disciplines is limited, likely because the tasks and goals usually differ. The domain of e-learning and knowledge acquisition constitutes a fruitful intersection for the two fields’ methodologies to be integrated because accurately tracking learning and forgetting over time and predicting future performance based on (...) learning histories are central to developing effective, personalized learning tools. Here, we show how a state-of-the-art ML model can be enhanced by incorporating insights from a cognitive model of human memory. This was done by exploiting the predictive performance equation's (PPE) narrow but highly specialized domain knowledge with regard to the temporal dynamics of learning and forgetting. Specifically, the PPE was used to engineer timing-related input features for a gradient-boosted decision trees (GBDT) model. The resulting PPE-enhanced GBDT outperformed the default GBDT, especially under conditions in which limited data were available for training. Results suggest that integrating cognitive and ML models could be particularly productive if the available data are too high-dimensional to be explained by a cognitive model but not sufficiently large to effectively train a modern ML algorithm. Here, the cognitive model's insights pertaining to only one aspect of the data were enough to jump-start the ML model's ability to make predictions—a finding that holds promise for future explorations. (shrink)

Dienes & Perner's (D&P's) target articles proposes an analysis of explicit knowledge based on a progressive transformation of implicit into explicit products, applying this gradient to different aspects of knowledge that can be represented. The goal is to integrate a philosophical concept of knowledge with relevant psychophysical and neuropsychological data. D&P seem to fill an impressive portion of the gap between these two areas. We focus on two examples where a full synthesis of theoretical and empirical data seems difficult (...) to establish and would require further refinement of the model: action representation and the closely related consciousness of action, which is in turn related to self-consciousness. (shrink)

This article asserts that traditionally dominant models of health promotion in the US are fairly characterized by methodological individualism. This schema produces a focus on the individual as the node of intervention. Such emphasis results in a number of scientific and ethical problems. I identify three principal ethical deficiencies: first, the health promotions used are generally ineffective, which violates canons of distributive justice because scarce health resources are expended on interventions that are unlikely to produce health benefits. Second, the health (...) promotions used tend to expand health inequalities between the affluent and the least well-off. Third, the health promotions used are likely to intensify stigma against the least well-off, a deficiency that itself may exacerbate the ‘densely-woven patterns of disadvantage’ that characterize life on the tail of the social gradient. Because Powers and Faden’s health sufficiency model of social justice argues that the amelioration of such clusters of disadvantage should be the primary ethical goal of public health policy, methodologically individualist models of health promotion are ethically deficient and should not stand as primary approaches for health promotion in a just social order. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Science Wars and BeyondHarold FrommScandalous Knowledge: Science, Truth and the Human, by Barbara Herrnstein Smith; viii & 198 pp. Durham: Duke University Press, 2005, $21.95 paper.Fear of Knowledge: Against Relativism and Constructivism, by Paul Boghossian; 139 pp. Oxford: Oxford University Press, 2006, $24.95.Barbara H. Smith, a professor of comparative and English literature at both Duke and Brown, has read widely in philosophy and the sciences. "Scandalous knowledge" is her (...) phrase to describe not the "science wars" (to use the title of the notorious Spring/Summer 1996 issue of Social Text) but the epistemology wars. The chief antagonists in these wars consist, on the one side, of traditional proponents of "classical" philosophy's normative, analytic, justifying, and stable methodologies and proponents, on the other, of such twentieth-century constructivist epistemologies as those of Ludwik Fleck, Thomas Kuhn, Michel Foucault, David Bloor, and Bruno Latour. "The scandal," Smith explains, is classical philosophy's "apparent inability to show how, when and why we can be sure that we know something or, indeed, that we know anything" (p. 1). In her well-executed Introduction, perhaps the best chapter in the book (for its panoramic picture of today's "Theory of Knowledge" conflicts), Smith prepares us for her espousal of constructivist methodologies but first distinguishes between "epistemological constructivism"—a philosophical methodology with an antagonism toward universal rationalities, philosophical "realism," in-itselfness, or [End Page 580] the Correspondence Theory of Truth—and the cultural critique often called "social constructionism," a distinction she acknowledges to be sometimes difficult and hazy. Social constructionism, a highly political activity, is critical of traditional notions of the normative and is engaged with the workings of cultural critics, ethicists, feminists, gender theorists, critics of institutional power, and the "goes without saying" of mainstream assumptions in the treatment of race, sexuality, the "natural" and the innate. In a word, the global conflict she describes is between "reason" (a contested term) and politics (not very contested, except for who and what are political), between the putative eternal verities of thought and the contingencies of daily life. Whereas a "constructivist" sociologist of science would stress the social, collective, intersubjective, institutional aspects of scientific knowledge, questioning "the standard understandings and treatments of such terms as fact, discovery, evidence, proof, objectivity and, of course, knowledge and science themselves" (p. 7), the "social constructionist" would be more likely to focus on class, politics, economics, and culture seen as a congeries of power structures.Smith is particularly distressed by the claims of traditional philosophy when she asks, "May it not be the case that the strict distinctions and divisions of labor that underwrite philosophy's self-honoring role in the study of science and knowledge beg all the relevant questions and, where maintained, insure philosophy's self-confinement?" (p. 10). She sees knowledge as assembled from multiple sources: philosophy, science, social sciences, human animality and subjectivity but she is not suggesting an abandonment of the notion of "truth," just a curbing of the notion of absolute knowledge, or knowledge of things-in-themselves (though even traditionalists believe being known can't be an aspect of a thing-in-itself.) In the process of constructing truths, "reason is not 'abandoned' for 'irrationalism'; scientific knowledge is not 'equated with' myth or ideology; and so forth... but are reconceived as variable gradients rather than fixed, distinct and polar opposites" (p. 11). She prefers to speak of the "superiority" of certain claims rather than their fixed universality via "rationalist-realist-positivist epistemology." As her overall theme, Smith wants to defend constructivist epistemology as the appropriate one for the twenty-first century and, to a slightly lesser extent, the goals of social construction, while deriding as unfounded the attacks against their purported relativism, nihilism, fatuous egalitarianism, and political correctness. Her performance is undeniably impressive but her success is mixed.The stronger first half of the book mounts a plausible defense of [End Page 581] constructivist epistemology. Starting off with a quick survey of "Pre-Post-Modern" relativists from Heraclitus to Wittgenstein, Smith moves on to twentieth-century modernist questioners of objectivist-universalist epistemes, from Heidegger and Einstein to Franz Boas, Edward Sapir, Lenin, and in the arts Woolf, Stravinsky... (shrink)

Leaves and flowers frequently have a characteristic rippling pattern at their edges. Recent experiments found similar patterns in torn plastic. These patterns can be reproduced by imposing metrics upon thin sheets. The goal of this paper is to discuss a collection of analytical and numerical results for the shape of a sheet with a non-flat metric. First, a simple condition is found to determine when a stretched sheet folded into a cylinder loses axial symmetry, and buckles like a flower. (...) General expressions are next found for the energy of stretched sheets, both in forms suitable for numerical investigation, and for analytical studies in the continuum. The bulk of the paper focuses upon long thin strips of material with a linear gradient in metric. In some special cases, the energy-minimizing shapes of such strips can be determined analytically. Euler–Lagrange equations are found which determine the shapes in general. The paper closes with numerical investigations of these equations. (shrink)

As more objections have been raised against grant peer-review for being costly and time-consuming, the legitimate question arises whether machine learning algorithms could help assess the epistemic efficiency of the proposed projects. As a case study, we investigated whether project efficiency in high energy physics can be algorithmically predicted based on the data from the proposal. To analyze the potential of algorithmic prediction in HEP, we conducted a study on data about the structure and outcomes of HEP experiments with the (...) goal of predicting their efficiency. In the first step, we assessed the project efficiency using Data Envelopment Analysis of 67 experiments conducted in the HEP laboratory Fermilab. In the second step, we employed predictive algorithms to detect which team structures maximize the epistemic performance of an expert group. For this purpose, we used the efficiency scores obtained by DEA and applied predictive algorithms – lasso and ridge linear regression, neural network, and gradient boosted trees – on them. The results of the predictive analyses show moderately high accuracy, indicating that they can be beneficial as one of the steps in grant review. Still, their applicability in practice should be approached with caution. Some of the limitations of the algorithmic approach are the unreliability of citation patterns, unobservable variables that influence scientific success, and the potential predictability of the model. (shrink)

Health regulators must carefully monitor the real-world safety and effectiveness of marketed vaccines through post-market monitoring in order to protect the public’s health and promote those vaccines that best achieve public health goals. Yet, despite the fact that vaccines used in collective immunization programmes should be assessed in the context of a public health response, post-market effectiveness monitoring is often limited to assessing immunogenicity or limited programmatic features, rather than assessing effectiveness across populations. We argue that post-market monitoring ought to (...) be expanded in two ways to reflect a ‘public health notion of post-market effectiveness’, which incorporates normative public health considerations: effectiveness monitoring should yield higher quality data and grant special attention to underrepresented and vulnerable populations; and the scope of effectiveness should be expanded to include a consideration of the various social factors that maximize a vaccine’s effectiveness at the population level, paying particular attention to how immunization programmes impact related health gradients. We use the case of the human papillomavirus vaccine in Canada to elucidate how expanding post-market effectiveness monitoring is necessary to close the gap between clinical practice and public health, and to ensure that vaccines are effective in a morally relevant sense. (shrink)

The results of an empirical study into the perceptions of “hands-on” experts concerning the welfare of (non-human) animals in traveling circuses in the Netherlands are presented. A qualitative approach, based on in-depth conversations with trainers/performers, former trainers/performers, veterinarians, and an owner of an animal shelter, conveyed several patterns in the contextual construction of perceptions and the use of dissonance reduction strategies. Perceptions were analyzed with the help of the Symbolic Convergence Theory and the model of the frame of reference, consisting (...) of knowledge, convictions, values, norms, and interests. The study shows that the debate regarding animals in circuses in the Netherlands is centered on the level of welfare that is required; the importance of animal welfare is not disputed. Arguments that were used differed according to the respondents’ specific backgrounds and can be placed on a gradient ranging from the conviction that the welfare of animals in circuses is sufficiently warranted and both human and animal enjoy the performance (right end), to the conviction that animal welfare in circuses is negative, combined with the idea that the goal of entertaining people does not outweigh that (left end). The study confirms that perceptions reflect people’s contexts, though the variety in scopes suggests that the (inter)relations between people and their context are complex in nature. Evidence of cognitive dissonance was abundant. Coping strategies were found to be used more by respondents towards the right end of the gradient, suggesting that those respondents experience more ambivalence. This encountered pattern of association between position on the gradient and frequency of dissonance reduction strategies calls for further research on the type of ambivalent feelings experienced. The authors argue that, to come to an agreement about the welfare of animals in circuses, including the way this welfare should be guaranteed, stakeholders from different contexts need to engage in a dialogue in which a distance is taken from right/wrong-schemes and that starts from acceptance of dilemmas and ambiguity. (shrink)

Knowing the level of quality from which the context is no longer valuable in a Context-Aware Data Mining (CADM) system is an important information. The main goal of this research is to study the variations of the predictions in case of different levels of noise and missing context data in practical scenarios for predicting soil moisture. The research has been performed on two locations from the Transylvanian Plain, Romania and two locations from Canada. The values predicted for the soil (...) moisture were compared in mixed scenarios that vary the quantity of noise and missing context data. The studied behavior was performed using Deep Learning, Decision Tree and Gradient Boosted Tree machine learning algorithms. It has been shown that when using the air temperature as context for predicting soil moisture, variations of noise and missing data do not influence the results proportionally with the levels of noise and missing data applied. Also, Gradient Boosted Tree algorithm proves to be the best algorithm from the ones studied, to be considered when predicting soil moisture with the CADM approach. (shrink)

How does sign language compare with gesture, on the one hand, and spoken language on the other? Sign was once viewed as nothing more than a system of pictorial gestures without linguistic structure. More recently, researchers have argued that sign is no different from spoken language, with all of the same linguistic structures. The pendulum is currently swinging back toward the view that sign is gestural, or at least has gestural components. The goal of this review is to elucidate (...) the relationships among sign language, gesture, and spoken language. We do so by taking a close look not only at how sign has been studied over the past 50 years, but also at how the spontaneous gestures that accompany speech have been studied. We conclude that signers gesture just as speakers do. Both produce imagistic gestures along with more categorical signs or words. Because at present it is difficult to tell where sign stops and gesture begins, we suggest that sign should not be compared with speech alone but should be compared with speech-plus-gesture. Although it might be easier (and, in some cases, preferable) to blur the distinction between sign and gesture, we argue that distinguishing between sign (or speech) and gesture is essential to predict certain types of learning and allows us to understand the conditions under which gesture takes on properties of sign, and speech takes on properties of gesture. We end by calling for new technology that may help us better calibrate the borders between sign and gesture. (shrink)

Byrne & Russon's target article displays all the difficulties encountered when one fails to take a methodological behaviourist approach to imitation. Their conceptual apparatus is grounded in a mixture of introspection and folk psychology. Their distinction between action-level and program-level imitation falters on goal imputation for sequential acts. In an alternative gradient descent model, behaviour can be simulated as a frustration/satisfaction gradient descent in the animal's “potentiality space,” as defined by knowledge, inventiveness, and the surrounding environment.

Contrary to Pothos, rule- and similarity-based processes cannot be distinguished by dimensionality. Rather, one must consider the goal of the processing: what the system will do with the resulting representations. Research on speech perception demonstrates that the degree to which speech categories are gradient (or similarity-based) is a function of the utility of within-category variation for further processing.

In recent years, with the continuous improvement of urban public transportation capacity, citizens’ travel has become more and more convenient, but there are still some potential problems, such as morning and evening peak congestion, imbalance between the supply and demand of vehicles and passenger flow, emergencies, and social local passenger flow surged due to special circumstances such as activities and inclement weather. If you want to properly guide the local passenger flow and make a reasonable deployment of operating buses, it (...) is necessary to grasp the changing law of public transportation short-term passenger flow. This paper builds a short-term passenger flow prediction model for urban public transportation based on the idea of integrated learning. The goal is to use the integrated model to accurately predict the short-term passenger flow of urban public transportation, using Multivariable Linear Regression, K-Nearest Neighbor, eXtreme Gradient Boosting, and Gated Recurrent Unit as the four seed models, and then use regression algorithm to integrate the model and predict the passenger flow, station boarding and landing, and cross-sectional passenger flow data of the typical representative line 428 in the “Huitian Area” of Beijing from January 1, 2020, to May 31, 2020. Finally, the prediction results of the submodels are compared with those of the integrated model to verify the superiority of the integrated model. The research results of this paper can enrich the short-term passenger flow forecasting system of urban public transportation and provide effective data support and scientific basis for the passenger flow, vehicle management, and dispatch of urban public transportation. (shrink)

The results of an empirical study into the perceptions of “hands-on” experts concerning the welfare of (non-human) animals in traveling circuses in the Netherlands are presented. A qualitative approach, based on in-depth conversations with trainers/performers, former trainers/performers, veterinarians, and an owner of an animal shelter, conveyed several patterns in the contextual construction of perceptions and the use of dissonance reduction strategies. Perceptions were analyzed with the help of the Symbolic Convergence Theory and the model of the frame of reference, consisting (...) of knowledge, convictions, values, norms, and interests. The study shows that the debate regarding animals in circuses in the Netherlands is centered on the level of welfare that is required; the importance of animal welfare is not disputed. Arguments that were used differed according to the respondents’ specific backgrounds and can be placed on a gradient ranging from the conviction that the welfare of animals in circuses is sufficiently warranted and both human and animal enjoy the performance (right end), to the conviction that animal welfare in circuses is negative, combined with the idea that the goal of entertaining people does not outweigh that (left end). The study confirms that perceptions reflect people’s contexts, though the variety in scopes suggests that the (inter)relations between people and their context are complex in nature. Evidence of cognitive dissonance was abundant. Coping strategies were found to be used more by respondents towards the right end of the gradient, suggesting that those respondents experience more ambivalence. This encountered pattern of association between position on the gradient and frequency of dissonance reduction strategies calls for further research on the type of ambivalent feelings experienced. The authors argue that, to come to an agreement about the welfare of animals in circuses, including the way this welfare should be guaranteed, stakeholders from different contexts need to engage in a dialogue in which a distance is taken from right/wrong-schemes and that starts from acceptance of dilemmas and ambiguity. (shrink)

It is widely recognized that mineral fertilizers must play an important part in improving agricultural productivity in western Kenyan farming systems. This paper suggests that for this goal to be realized, farmers’ knowledge must be strengthened to improve their understanding of fertilizers and their use. We analyzed smallholder knowledge of fertilizers and nutrient management, and draw practical lessons from empirical collective fertilizer-response experiments. Data were gathered from the collective fertilizer-response trials, through focus group discussions, by participant observation, and via (...) in-depth interviews representing 40 households. The collective trials showed that the application of nitrogen (N) or phosphorous (P) alone was insufficient to enhance yields in the study area. The response to P on the trial plots was mainly influenced by incidences of the parasitic Striga weed, by spatial variability or gradients in soil fertility of the experimental plots, and by interactions with N levels. These results inspired farmer to design and conduct experiments to compare crop performance with and without fertilizer, and between types of fertilizers, or responses on different soils. Participating farmers were able to differentiate types of fertilizer, and understood rates of application and the roles of respective fertilizers in nutrient supply. However, notions were broadly generated by unsteady yield responses when fertilizers were used across different fertility gradients, association with high cost (especially if recommended rates were to be applied), association of fertilizer use with hybrids and certain crops, historical factors, among other main aspects. We identified that strengthening fertilizer knowledge must be tailored within existing, albeit imperfect, systems of crop and animal husbandry. Farmers’ perceptions cannot be changed by promoting more fertilizer use alone, but may require a more basic approach that, for example, encourages farmer experimentation and practices to enhance soil properties such as carbon build-up in impoverished local soils. (shrink)

An account of predicate reference is presented which attempts to steer a middle course between reductionism, which construes the notion in terms of speakers' inclinations, and {transcendent) realism, which construes the notion in terms of properties. It is first introduced in the context of a discussion of the accounts of length (distance) advanced by Hans Reichenbach, Adolf Grünbaum and Hilary Putnam. A general account of predicate reference is then developed that explains the notion in terms of speakers' inclinations, while rejecting (...) the idea that this explanation should take the form of a reduction. The view is presented as a vindication of extreme nominalism, as it explains predicate reference solely in terms of the notion of qualia introduced by C.I. Lewis and developed by Nelson Goodman, which, it is argued, is definable in terms of speakers' classificatory propensities. Some connections are explored between the position that is presented and the views of Michael Dummett, John McDowell, Mark Johnston and Hilary Putnam, among others. (shrink)

First published in English in 1953, this important book from eminent philosopher Karl Jaspers deals with the philsophy of the history of mankind. More specifically, its avowed aim is to assist in heightening our awareness of the _present_ by placing it within the framework of the long obscurity of prehistory and the boundless realm of possibilities which lie within the undecided future.This analysis is split into 3 parts: World history The present and the future The meaning of history.

This book is an analysis of the distinctive form of reasoning, called practical reasoning by Aristotle (as opposed to theoretical reasoning), that serves to guide behaviour.

Many have the intuition that the right response to the Lottery Paradox is to deny that one can justifiably believe of even a single lottery ticket that it will lose. The paper shows that from any theory of justification that solves the paradox in accordance with this intuition, a theory not of that kind can be derived that also solves the paradox but is more conducive to our epistemic goal than the former. It is argued that currently there is (...) no valid reason not to give preference to the derived accounts over the accounts from which they come. (shrink)

Understanding the goals of others is fundamental for any kind of interpersonal interaction and collaboration. From a neurocognitive perspective, intention understanding has been proposed to depend on an involvement of the observer’s motor system in the prediction of the observed actions. An open question is if a similar understanding of the goal mediated by motor resonance can occur not only between humans, but also for humanoid robots. In this study we investigated whether goal-oriented robotic actions can induce motor (...) resonance by measuring the appearance of anticipatory gaze shifts to the goal during action observation. Our results indicate a similar implicit processing of humans’ and robots’ actions and propose to use anticipatory gaze behaviour as a tool for the evaluation of human-robot interactions. Keywords: Humanoid robot; motor resonance; anticipation; proactive gaze; action understanding. (shrink)

In the current debate on economic rationality, Amartya Sen's analysis of the structure of commitment plays a uniquely important role . However, Sen is not alone in pitting committed action against the standard model of rational behavior. Before turning to Sen's analysis in section 2 of this paper, I shall start with an observation concerning some of the other relevant accounts.

First published in English in 1953, this important book from eminent philosopher Karl Jaspers deals with the philsophy of the history of mankind. More specifically, its avowed aim is to assist in heightening our awareness of the present by placing it within the framework of the long obscurity of prehistory and the boundless realm of possibilities which lie within the undecided future.This analysis is split into 3 parts: World history The present and the future The meaning of history.

Wason's standard 2-4-6 task requires discovery of a single rule and leads to around 20% solutions, whereas the dual goal (DG) version requires discovery of two rules and elevates solutions to over 60%. We report an experiment that aimed to discriminate between competing accounts of DG facilitation by manipulating the degree of complementarity between the to-be-discovered rules. Results indicated that perfect rule complementarity is not essential for task success, thereby undermining a key tenet of the goal complementarity account (...) of DG facilitation. The triple heterogeneity account received a good degree of support since more varied triple exploration was associated with facilitatory DG conditions, in line with this account's prediction that task success is associated with the creative search of the problem space. The contrast class account (an extension of Oaksford & Chater's, 1994, iterative counterfactual model) was also corroborated in that the generation of descending triples was demonstrated to be the dominant predictor of DG success. We focus our discussion on conceptual ideas relating to the way in which iterative counterfactual testing and contrast class identification may work together to provide a powerful basis for effective hypothesis testing. (shrink)