Clements: “3357_c036” — 2007/11/9 — 18:40 — page 811 — #1 Part VI Ecotoxicology: A Comprehensive Treatment—Conclusion © 2008 by Taylor & Francis Group, LLC Clements: “3357_c036” — 2007/11/9 — 18:40 — page 813 — #3 36 Conclusion 36.1 OVERARCHING ISSUES science students accept theories on the authority of teacher and text, not because of evidence. (Kuhn 1977) Except in their occasional introductions, science textbooks do not describe the sorts of problems that the professional may be asked to solve and the variety of techniques available for their solution. Rather, these books exhibit concrete problem solutions that the profession has come to accept as paradigms [however, students] must, we say, learn to recognize and evaluate problems to which no unequivocal solution has been given; they must be supplied with an arsenal of techniques for approaching these future problems (Kuhn 1977) So what is left to say? The twin goals of differentiation and integration (see Section 1.1) were attained in Chapters 1 through 35. Facts and paradigms 1 relevant at each level of the biological hierarchy were presented and then interconnected as much as presently possible. Relative to the conduct of normal science, 2 this will foster the “determination of significant fact, matching of facts with theory, and articulation of theory” (Kuhn 1970) at all relevant scales. Hopefully, an appropriate balance was achieved by including more ecology than usually found in ecotoxicology primers. The imbalance between autecotoxicological and synecotoxicological themes is generally recognized as an important shortcoming of ecotoxicology as currently practiced (e.g., Cairns 1984, 1989; Chapman 2002). Amore congruent treatment was also attempted by including relevant human effects information rather than taking the contrived approach of “asking humans to step out of the picture” when discussing human influences on the biosphere. As justifying examples, discussion of multidrug resistance transporter proteins (Chapter 3), inflammation (Chapter 4), endocrine modifiers (Chapter 5), Seyle’s General Adaptation Syndrome (Chapter 9), and human epidemiology metrics (Chapter 13) surely provided enriching detail to considerations of contaminant effects on nonhuman individuals and populations. So, what more can be said? The last important issues to be explored are ways of recognizing when innovation is needed and the best way of fostering change in this extremely important science. Statements about possible changes to the science of ecotoxicology were made throughout this book. Yet, other than some general discussion in Chapter 1, no specific advice was given about how exactly one recognizes the need for and then contributes to healthy change. As expressed in Kuhn’s quote above, the absence of this kind of guidance is a fundamental shortcoming of most textbooks. To avoid committing such a sin of omission, this chapter provides context and specific advice about recognizing and then contributing to necessary change. Effective change is particularly crucial in our applied science in which much harm can be done to the biosphere and our well-being if a failing 1 Kuhn’s concept of scientific paradigm is applied here because it is as useful as it is hackneyed. According to Kuhn (1970), paradigms are “universally recognized scientific achievements that for a time provide model problems and solutions to a community of practitioners.” They are the best explanations or approaches currently available to the scientific community. 2 Activities of scientists are divided into normal and innovative science (Kuhn 1970). When participating in innovative science, a scientist intends to directly challenge an existing paradigm, or to propose a novel one. In contrast, the practice of normal science involves filling in or refining important details surrounding an existing paradigm, or building ancillary concepts or connections that reinforce or enrich a current paradigm. Normal and innovative science are complementary activities essential to the health of any science. 813 © 2008 by Taylor & Francis Group, LLC Clements: “3357_c036” — 2007/11/9 — 18:40 — page 814 — #4 814 Ecotoxicology: A Comprehensive Treatment paradigm is maintained too long. The emerging global warming paradigm is one example where irreparable harm ata global scale could occur if effective paradigmscrutiny and possible replacement were put off any longer. The approach here will be to focus on foibles impeding innovation, hoping that understanding impediments helps minimize their influence. For if we learn more about resistance to scientific discovery, we shall know more also about the sources of acceptance, just as we know more about health when we successfully study disease. By knowing more about both resistance and acceptance in scientific discovery, we may be able to reduce the former by a little bit and thereby increase the latter in the same measure. (Barber 1961) General cognitive and social psychology concepts will be blended with those more directly concerned with sciences. General psychological concepts were included because understanding them is pivotal to understanding how ecotoxicology might be moved out of its scientific nonage. As put simply by Bourdieu (2004), “ the obstacles to the progress of science are fundamentally social.” Footnotes will be applied liberally to improve continuity despite numerous digressions about unfamiliar materials. 36.1.1 GENERATING AND INTEGRATING KNOWLEDGE IN THE HIERARCHICAL SCIENCE OF ECOTOXICOLOGY The ecotoxicologist’s vocation is eminently important and enormous. In our opinion, this new science could emerge as one of the most important for addressing society’s major challenges of the millennium. The working knowledge needed to make useful ecotoxicological predictions spans broad temporal, spatial, and informational content scales (Figure 36.1). Outstanding challenges are the full articulation of major issues, development of predictive tools for handling problems arising at every scale, and most critically, the integration of concepts and tools for every scale into Temporal Spatial Informational Explanation Obser vation Significance Cell/tissue Molecule Organ(s) Organism Community Significance Observation Explanation Ecosystem Biosphere Population FIGURE 36.1 The temporal, spatial, and informational complexity scales relevant to ecotoxicology. In order for ecotoxicology to emerge as a self-consistent science, more integration of facts and paradigms is essential along all three scales. The explanation–observation-significance concatenation described in Chapter 1 is equally useful at any level from molecule to biosphere. Although applied most often from the lower (explanation) to higher (significance) levels, this concatenation is often useful in the opposite (“top-down”) direction. © 2008 by Taylor & Francis Group, LLC Clements: “3357_c036” — 2007/11/9 — 18:40 — page 815 — #5 Conclusion 815 a congruent whole. A haphazard “feeling our way” (Platt 1964) approach is insufficient for this task so thoughtful discussion is needed to meet these challenges. Heterophilous 3 communications between dissimilar individuals may cause cognitive dissonance because an individual is exposed to messages that are inconsistent with existing beliefs, an uncomfortable psychological state. (Rogers 1995) Homophily can act as an invisible barrier to flow of innovations within a system. New ideas usually enter a system through higher status and more innovative members. A high degree of homophily means that these elite individuals interact mainly with each other, (Rogers 1995) Fundamental social processes determine how readily a novel idea, vantage, or technique dif- fuses into any group, including a scientific community. 4 The only, albeit important, distinction between scientific and nonscientific communities is the rules by which beliefs acquire favored status (Chapter 1). Despite this distinction, scientists remain subject to rules governing acceptance of ideas and innovation in any social group. As stated by Barber (1961), the rational, open-minded tradi- tion has a powerful influence in scientific communities yet it “works in conjunction with a number of other cultural and social elements, which sometimes reinforce it, sometimes give it limits.” As reflected in the above quotes, an obstacle to accepting new ideas is often the barrier presented by homophily: scientists trained in a particular discipline encounter cognitive dissonance, resist, and then react against ideas from outside their immediate training or practice; for example, a systems ecologist’s negative response to ideas of a mammalian toxicologist or vice versa. The discomfort invoked by dissonance prompts a person to seek association with those sharing similar ideas and to actively thwart, or minimally isolate, those with different ideas. Most likely, this is the true root of the distracting reductionism–holism debate criticized inChapters 1 (Section 1.2) and20 (Section 20.2.1), not any definitive superiority of one or the other as an investigative vantage. These dynamics are altered only when the discomfort of maintaining a failing paradigm or stance becomes harder to bear than that associated with confronting cognitive dissonance. Kuhn (1977) describes such a crisis in scientific communities as one of “pronounced professional insecurity” that forces resolution. Con- trary to popular belief, 5 most scientists only abandon “the idol of certainty” (Popper 1959) under duress. Described as an essential tension by Kuhn (1970, 1977), scientists resist the discomfort of change until that of bolstering a failing paradigm becomes harder to bear. It should come as no surprise that strong conformists are most often the opinion leaders of groups, including those of scientific communities, and innovators are the most actively censored members (Bourdieu 2004, Rogers 1995) except during special occasions requiring change. It is our opinion that ecotoxicology is in a period of tension relative to the integration of core concepts from all pertinent scales of organization. Out of immediate necessity, the individual-based paradigms and approaches of mammalian toxicology were wisely adopted in our young science to address immediate problems. However, enough data and collective experience has accumulated to expose the discomforting inconsistencies among level-specific paradigms and approaches that, together, constitute a self-contradictory system. For example, most risk assessments reluctantly 3 Homophily is the degree to which two interacting or communicating individuals are similar in relevant attributes. The opposite of homophily is heterophily (McPherson et al. 2001, Rogers 1995). 4 A scientific community is a “group whose members are united by a common objective and culture” (Hagstrom 1965). 5 Typifying the presumption of scientists being open-minded is Berkeley’s quote, “He must surely be either very weak, or very little acquainted with the sciences, who shall reject a truth, that is capable of demonstration, for no other reason but because it is newly known and contrary to the prejudices of mankind” (Berkeley 1710). In reality, strong-willed and informed scientists often display these behaviors. Barber (1961) provides an insightful counterpoint to this conventional image. © 2008 by Taylor & Francis Group, LLC Clements: “3357_c036” — 2007/11/9 — 18:40 — page 816 — #6 816 Ecotoxicology: A Comprehensive Treatment ignore central ecological principles, relying on LC50 and NOEL data for effects to individuals. Recently, a pragmatic species sensitivity distribution approach combining individual LC50 or NOEC values has been proposed to estimate a concentration protective of ecosystems (see Posthuma et al. 2002 for details). Such tests tacitly ignore critical species interactions such as those described in Chapter 27 among killer whales, pinnipeds, otters, urchins, and kelp. 6 As explained by Popper (1959), such self-contradictory systems eventually fail because they are uninformative systems from which “ no statement can be singled out, either as incompatible or as derivable, since all are derivable.” As evidenced in the primary literature and reflected in this textbook, a paradigm shift seems to have begun in which ecological paradigms and techniques are applied in an increasingly congruent and concerted manner with those emerging from mammaliantoxicology. In times likethis, the ideal opinion leader is more innovative than typical and innovators are given more credibility than otherwise warranted. 7 Ecotoxicology will shatter into a loose collection of interface discip- lines (Odum 1996) in the absence of such leadership and the recognition of contributions made by innovators. Sociology provides clues about how best to act as an individual practitioner in a science under- going necessary change. The most useful is related to the above discussion of homophilic and heterophilic diffusion of innovations. Homophilic communication, the form of exchange that is most frequent and least likely to produce cognitive dissonance, is also the form least likely to contain novel information with which to solve an emerging problem. The more challenging and frustrating, heterophilic communication is more likely to produce rapid diffusion of crucial know- ledge into one’s evolving social group. This is the basis of the Strength of Weak Ties Theory, i.e., weak, heterophilic communication forms bridging links containing the most novel information with which to address challenges faced by a social group (Rogers 1995). What is the specific mes- sage to be taken from this by a nonleader practitioner of ecotoxicology today? Instead of seeing ecotoxicologists working at a different scale than your immediate group as erring competitors to be coped with, consider the possibility that your scientific activities would be most enhanced by exploring the vantage or ideas of these heterophilic ecotoxicologists. In doing this, strong emphasis should be on discovering consistency among levels and enriching interpretation at any particular level. Heterophilic communication among ecotoxicologists working at different hierarchical levels is not enough to meet the challenge: the communication must also be thoughtful in order to reach sound judgments. For example, satisficing is a common danger in decision making by well-intended individuals. Satisficing is a flawed form of decision making that often emerges in groups of indi- viduals with very different agendas and vantages (i.e., heterophilic groups). Instead of seeking the best possible decision, the group takes “a course of action that is ‘good enough,’ that meets a minimal set of requirements” of all parties (Janis and Mann 1977). The operating premise is that a “barely ‘acceptable’ course [is] better than the way things are now.” Janis and Mann (1977) and similar books ondecision making theory and practiceprovide concrete meansof minimiz- ing suboptimal heterophilic interactions like satisficing. Certainly, the influence of satisficing during heterophilic scientific deliberations can be reduced by adopting Chamberlin’s multiple working hypothesis scheme (Chamberlin 1897) in combination with Bayesian abductive inference methods 6 This is an example of the behavior called collusive lying, that is, “two parties, knowing full well that what they are saying or doing is false, collude in ignoring the falsity” (Bailey 1991) (see also Section 16.4). It is a technique of groups attempting to establish a useful paradigm in which they push away an inconsistent fact until the fledgling paradigm has been given sufficient clarity and detail to be assessed properly. Unfortunately, this understandable behavior also carries the risk of uncritical acceptance by the ecotoxicology community based on the stature of advocates with consequent long delay in eliminating such a compromised paradigm when its shortcomings are eventually revealed. 7 It is equally important to understand that innovators are very poor opinion leaders when no change is needed (Rogers 1995). Their distracting exploration of unhelpful innovations can slow the accumulation of facts and ancillary concepts by normal science around useful, established paradigms. © 2008 by Taylor & Francis Group, LLC Clements: “3357_c036” — 2007/11/9 — 18:40 — page 817 — #7 Conclusion 817 (Howson and Urbach 1989, Josephson and Josephson 1996, Pearl 2000) that will be discussed at the end of this chapter. 36.1.2 OPTIMAL BALANCE OF IMITATION,INNOVATION, AND INFERENCE Transmission [of ideas and innovations] withers on the vine when the present is taken as the only model. And innovation itself withers with it, scorn for the past being the greatest enemy of progress. (Debray 2000) Very often the successful scientist must simultaneously display the characteristics of the traditionalist and of the iconoclast. 8 (Kuhn 1977) In the rest of this chapter, we try to sketch out the most efficient way of incorporating crucial innovations while preserving existing, valuable ecotoxicological theory and practice. The next two sections explore the relative virtues of resisting and embracing change to scientific knowledge. 36.1.2.1 The Virtues of Imitation Among the forces that support social rules there is the imperative of regularization of “falling into the line with the rule” (Bourdieu 2004) The dominant players [in a science] impose by their very existence, as a universal norm, the principles that they engage in their own practice. This is what is called into question by revolutionary innovation A major scientific innovation may destroy whole swathes of research and researchers as a side-effect, without being inspired by the slightest intention of doing damage It is not surprising that innovations are not well received, that they arouse formidable resistance (Bourdieu 2004) Invention of alternates is just what scientists seldom undertake except during the pre-paradigm stage of their science’s development and at very special occasions during its subsequent evolution. So long as the tools a paradigm supplies continue to prove capable of solving the problems it defines, science moves fastest and penetrates most deeply through confident employment of those tools. The reason is clear. As in manufacture so in science retooling is an extravagance to be reserved for the occasion that demands it. (Kuhn 1977) Change isresisted for obvious reasons, some high minded, and othersnot. Often ascientist’s behavior and activities have committed them to a paradigm that is now questioned, resulting in their beliefs and hard work also being questioned—“A threat to theory is therefore a threat to the scientific life” (Kuhn 1977). To expect open and immediate acceptance from such a scientist is to expect the superhuman. Such a person will resist dismissing the value of their past work or giving up their hard-earned professional status. More importantly, if a certain level of resistance to change were not present in a scientific community, forward progress would be stymied by frequent detours or side trips to explore novel paradigms that eventually turned out to be dead ends. That is the point being made in the quote above from Kuhn (1977). It is inefficient to keep “retooling” a science 8 Kuhn (1977) adds an important footnote to this statement, “Strictly speaking, it is the professional group rather than the individual scientist that must display both these characteristic simultaneously.” © 2008 by Taylor & Francis Group, LLC Clements: “3357_c036” — 2007/11/9 — 18:40 — page 818 — #8 818 Ecotoxicology: A Comprehensive Treatment when there is no need. Furthermore, Loehle (1987) notes that insistence on testing and potentially rejecting a concept before sufficient related details have accumulated by normal science can lead to premature (“dogmatic”) falsification of a perfectly sound paradigm. A current case in point is the species sensitivity distribution approach mentioned briefly above. There is real virtue to healthy resistance to changewhenfaced withanovel explanation orsolution. The keyis avoiding pathological resistance. 36.1.2.2 The Wisdom of Insecurity Our innate social psychology is probably that bequeathed to us by our Pleistocene ancestors. (Richerson and Boyd 2005) We have analyzed this problem using several mathematical models of the evolution of imitation, and all of them tell the same story. Selection favors a heavy reliance on imitation whenever individual learning is error prone or costly, and environments are neither too variable nor too stable. When these conditions are satisfied, our models suggest that natural selection can favor individuals who pay almost no attention to their own experience, and are almost totally bound to what Francis Bacon called the “dead hand of custom.” (Richerson and Boyd 2005) social influences exist that tend to form habits of thought leading to inadequate and erroneous beliefs. (Dewey 1910) As evidenced by the above quotes, the strategy of imitation—uncritical acceptance of actions or beliefs of those around us—is prominent in human interactions. Evolution favored imitation in our Pleistocene ancestors as they attempted to survive in bands of hunter-gatherers. It remains intact in modern social groups (Richerson and Boyd 2005), including scientific communities. However, modern groups exist in a very different environment and have goals other then hunting and gath- ering: sometimes our evolved behaviors remain useful, but in others, they are maladaptive. One healthy modern manifestationis informational mimicry, a behavior in financial corporations in which a group mimics another particularly knowledgeable group, rather than attempting to formulate its own strategy (Vernimmen et al. 2005). A maladaptive example is faculty mobbing, an odd tendency of university faculty to mob 9 overachieving members “who stand out from the crowd,” endangering the common good (Westhues 1998, 2005). These evolved strategies, which were optimized for Pleis- tocene hunter-gatherers social groups, arguably do not always result in optimal fitness of a modern group of scientists and, consequently, require some understanding and coping behavior. As already discussed, optimal fitness relative to a scientific community’s goal involves a thoughtful balance of adherence to traditional explanation (mimicking) and openness to plausible alternatives. Imitation has clear advantages as long as a minimum number of competent innovators exist when change is required. A group’s ability to respond to change is placed at risk when too few innovators exist, either because of too active exclusion or because of passive neglect in teaching innovation skills. Clearly articulating to students the valued role of innovation and then actively teaching problem solving skills are two pedagogical necessities in a healthy modern science, especially a nascent one like ecotoxicology. Fitting Gigerenzer’s (2000) metaphor to the present topic, trying to change a scientific discipline can be like trying to move a cemetery. Given the social psychological backdrop described above, the 9 “Workplace mobbing is ‘a common and bloodless form of workplace mayhem’ (Maguire 1999), usually carried out politely and without violence” (Westhues 2005). © 2008 by Taylor & Francis Group, LLC Clements: “3357_c036” — 2007/11/9 — 18:40 — page 819 — #9 Conclusion 819 challenge for leaders in our field is facilitating necessary change in the presence of natural resistance. An inappropriately conservative (or innovative) opinion leader will be swept aside after a period of ineffective confusion. The challenge for opinion leaders is discerning when and where innovation is truly needed. Amajor component of any solution is adopting a way of reliably discerning the relative plausibility of candidate explanations, and then effectively updating these plausibility estimates as new information emerges from normal science activities. An ideal system would allow the most effective identification and then communication of the need for change to the group’s members. Such a system should be resistant to processes such as satisficing or groupthink (a suboptimal process prevalent in homophilic group decision making in which group concurrence is the objective, not the best decision Box 36.1) (Janis and Mann 1977). Unfortunately, the unstructured expert opinion systems on which we currently depend for making regulatory and many scientific judgments are prone to these kinds of decision making errors (Cooke 1991). The approach of melding Chamberlin’s multiple working hypothesis schemes and Bayesian abductive inference methods described at the end of this chapter provides one possible means of doing this. Box 36.1 Minimizing Groupthink Groupthink, a pervasive problem in homophilic group decision making, has significantly impacted our recent history. A classic example is the flawed decision making that occurred in the Kennedy administration that led to the failed Bay of Pigs invasion. More recently, NASA groupthink contributed substantially to the 1986 Challenger space shuttle disaster. Groupthink will be examined closer here because of our pervasive dependence on the error-prone expert opinion approach for establishing much ecotoxicological consensus and assessing ecological risk. Although underexploited by natural scientists in their decision making, there are simple ways of reducing groupthink’s influence during group activities. The qualitiesof groupthinkare described by Janis and Mann (1977). Importantly, groupthink occurs with “in-groups” (homophilic groups) in which concurrence is a highly valued charac- teristic of the group dynamics. Rationalizations are invoked to preserve and foster concurrence. In-groups experiencing groupthink often manifest eight characteristics: 1. Members tend to feel minimally vulnerable to mistakes and become overconfident in their abilities. Consequently, they take on more risk in decisions than warranted by facts. 2. There is a consorted effort to dismiss contrary facts or opinions, and to rationalize. 3. The group’s “inherent morality” becomes a given during deliberations. 4. Foibles are exaggerated and strengths trivialized for rivals or those with contrasting opinions. 5. Direct pressure is applied to any member who questions the group’s actions or stances. 6. Members who have doubts practice self-censoring in which they remain silent despite their misgivings. 7. That silence indicates concurrence is a shared assumption of the group. 8. Self-appointed “mindguards”emerge whoaggressively act to protect thegroup from erring members or information inconsistent with emerging consensus. Groupthink can erode the quality of a group’s deliberations. Fortunately, there are means of reducing its influence (Table 36.1). Panels, committees, and less-formal scientific teams can benefit greatly from being aware of them. It is easy to imagine groupthink emerging during a panel’s deliberations when applying Fox’s or Miller’s qualitative rules (see Section 13.2.1 and Box 13.2 in Chapter 13, and Box 22.3 in Chapter 22) or codified Environmental Protection © 2008 by Taylor & Francis Group, LLC Clements: “3357_c036” — 2007/11/9 — 18:40 — page 820 — #10 820 Ecotoxicology: A Comprehensive Treatment TABLE 36.1 Tools for Reducing Groupthink 1. The leader or empowering agency should objectively emphasize the need for impartiality at the onset of the decision- making process. 2. The leader or empowering agency should state the importance of expressing objections and concerns, making this an obligation of each group member. 3. One member of the group should be assigned the role of skeptic or challenger during each decision-making session. 4. Perhaps by dividing the group occasionally to conduct separate assessments, the group should periodically assess the feasibility of the group’s current stance. 5. If a rival group with contrasting views can be identified, enough members of that group should be as engaged as possible in establishing possible alternate decisions. 6. After the consensus-building meetings have occurred, a “second chance upon reflection” meeting should be planned to air any concerns emerging after the group breaks up. 7. Significant experts not associated with the core group should be invited to engage with the group with the request to act as a “fresh pair of eyes.” 8. Each group member should be asked to discuss the group’s thoughts and progress with trusted peers and report back the results of these independent exchanges. 9. If possible, separate groups can beestablished that address the same problemor question. The decisions from different groups are then used to come to a final decision. Source: Summarized from pages 399–400 of Janis and Mann (1977). Agency (EPA) guidance (2000) to determine the cause or risk associated with a particular scenario. 36.1.2.3 Strongest Possible Inference: Bounding Opinion and Knowledge It is therefore worth while to search out the bounds between opinion and knowledge. (Locke 1690, reprinted 1959) What current approach best balances conceptual stability and change? How can we define the bounds between mere opinion and sound knowledge? Clues can be found in many places. Some may be familiar while others may induce a level of discomfort, which was identified earlier as a characteristic of heterophilic exploration of concepts. Previously, we explored the concept of strong inference as articulated in the classic Science paper by Platt (1964). The conventional Baconian scientific method is advocated by Platt with emphasis being placedon consistent applicationof such aninductiveinference approachina scientific discipline. He holds up as an exemplary example of a conditional logic tree the process that a chemist might employ to qualitatively determine the nature of a substance. A series of positive/negative tests are conducted in an exclusionary manner until only one possibility remains. Unfortunately, there are substantial shortcomings associated with advocating such an approach as the kingpin of scientific inquiry. Even assuming that the qualitative(positive/negative) natureof sucha processis adequatefor all tasks, the presence of Type I and II error ratesrestricts the value of such a simple approach, making it prone to error in the hands of the naïve practitioner (e.g., Box 10.2). Type I and II errors must be considered in orderto make sensibledecisions.Also, manyecotoxicological judgments ofplausibility are based on quantitative information for which such a dichotomous approach is suboptimal or prone to logical error (see again Box 10.2). Some require the adaptive inference strategy described in Section 29.5.3. An even more serious problem with using such a strictly Popperian falsification scheme arises from trying to incorporate the second major component of Platt’s strong inference approach, the © 2008 by Taylor & Francis Group, LLC Clements: “3357_c036” — 2007/11/9 — 18:40 — page 821 — #11 Conclusion 821 method of multiple hypotheses, which Platt (1964) claims to be “ the second great intellectual invention which is what is needed to round out the Baconian scheme.” Chamberlin’s (1897) multiple hypotheses approach attempts to reduce the bias toward any particular hypothesis(ses) during testing by requiring that all plausible hypotheses be given equal amounts of effort during testing. Unfortunately, adhering tothis approachis extremelydifficult and often becomes contrived in ecotoxicology. The complexity (high dimensionality) and high uncertainty of many ecotoxicological issues limits the value of any testing method that requires the classic dichotomous “accept/reject” context advocated by Popper and Platt, and institutionalized in Fisher’s significance testing. While current null hypothesis-based testing remains invaluable, dogmatic rejection of any other logical approach of gauging plausibility of an explanation creates an impasse for the ecotoxicologist. As long as there is an institutionalized [null hypothesis testing] methodology that does not encourage researchers to specify their hypotheses, there is little incentive to think hard and develop theories from which such hypotheses could be derived. (Gigerenzer 2000) Fortunately, an approach for reducing these difficulties exists for which the approach advocated by Platt(1964) is a special case. Itis calledthe Strongest PossibleInference approachin this bookonly for the purposes of identifying it as a simple extension of Platt’s Strong Inference and emphasizing the conditional nature of any ensuing judgments of scientific hypothesis/explanation plausibility. It is not novel, being a straightforward application of quantitative abductive inference. The strongest possible inferences available to ecotoxicologists can be made at this time with abductive inference as formalized in Bayesian inference formulations. 10 Associated Bayesian methods are pervasive and widely available, and many textbooks (e.g., Gelman et al. 1995, Neapolitan 2004, Pearl 2000, Woodworth 2004) and software [e.g., Netica ® (Norsys Software)] facilitate their implementation. Explanation of Strongest Possible Inference will begin by repeating Locke’s premise that “our assent ought to be regulated by the grounds of probabilities” (Locke 1690). This seventeenth-century quote contains the essence of abductive inference and Bayesian statistical inference. Abductive inference is simply inference that favors the most probable explanation or hypothesis (Newman and Evans 2002). Josephson and Josephson (1996) use the following syllogism for abductive inference: D is a data collection about a phenomenon. H explains the data collection, D. No alternate hypothesis (H A ) explains D as effectively as H does. ∴ H is probably true. The key to applying abductive inference is quantifying “as effectively as” and “probably.” Bayesian techniques permit quantification of abductive inference. The logic can be shown for using data to judge a single hypothesis: D provides support for H if P(H | D)>P(H). D draws support away from H if P(H | D)<P(H). D provides neither undermining nor supportive information if P(H | D) = P(H). where P(H) = the probability of the hypothesis being true before any consideration of the data, and P(H | D) = the probability of the hypothesis being true given the data. The task becomes estimating the probabilities. Evidenceis combinedwith aprior probabilityof H being trueto producea statement of probability given the evidence—a new probability of an explanation being true is established. If more evidence (D NEW ) was then collected during an inquiry, the newly established probability can be used as the new “prior probability” 11 and combined with D NEW to calculate a new post 10 See Boxes 10.2 and 13.3 as instances in which we have already applied Bayesian methods for this purpose. 11 The probability is a “prior probability” relative to the collection of the new data. © 2008 by Taylor & Francis Group, LLC [...]... “3357_c 036 — 2007/11/9 — 18:40 — page 822 — #12 Conclusion Box 36. 2 823 Fish Kills due to Toxic Dinoflagellate Blooms or Hypoxia? P piscicida was implicated as the causative agent of 52 ± 7% of the major fish kills on an annual basis in North Carolina estuaries and coastal waters (Burkholder et al 1995) A series of large fish kills began in mid-Atlantic USA estuaries and coastal waters in the early 1990s... Essential Tension, The University of Chicago Press, Chicago, IL, 1977 Lane, D .A. , Subjective probability and causality assessment, Appl Stochastic Models Data Analy., 5, 53–76, 1989 Lane, D .A. , Kramer, M.S., Hutchinson, T .A. , Jones, J.K., and Naranjo, C., The causality assessment of adverse drug reactions using a Bayesian approach, Pharmaceut Med., 2, 265–283, 1987 Locke, J., An Essay Concerning Human... advantage of Bayesian inference is the ability to quantitatively express the degree of belief warranted by evidence in a particular explanation Any quantitative expression can be Large fish kill Yes 0.081 (810) No 0.919 (9190) High Pfiesteria Yes 0.520 421 Cases of kills with Pfiesteria FIGURE 36. 2 An example of applying Bayesian inference using natural frequencies Probabilities are placed alongside arrows... of a set of alternate explanations can be judged using evidence-based probabilities These estimates of belief warranted by evidence can be recalculated periodically, and associated explanations reinforced or discarded as evidence accumulates Calculations can include the simple “accept/reject” context described by Popper (1959), or more complex contexts with higher uncertainty An excellent illustration... evidence is obtained The equations above also suggest what information is most needed to permit belief-based action (i.e., funding and legislative decision making) to be effectively aligned with or withdrawn from a particular explanation In this case, more accurate and precise information for the associated probabilities would be extremely helpful for both the hypoxia and Pfiesteria explanations for fish... this chapter, information created via normal science has succeeded in producing enough cognitive dissonance that change in existing paradigms must occur Suggestions about how an ecotoxicologist might recognize and facilitate effective change are provided and a Strongest Inference Possible approach advocated as the best means of judging the relative merits of hypotheses or explanations in situations ranging... available, it can be modified again This same process can be applied to judging any hypothesis against its negation (∼H), a single alternate (HA ), several alternate hypotheses (e.g., HA1 , HA2 , HA3 ) Equation 36. 3 illustrates how the posterior odds for H versus HA being true (P(H | D)/P(HA | D)) can be calculated from the prior odds (P(H)/P(HA )) and likelihood ratio (P(D | H)/P(D | HA )): P(H) P(D... Bayesian Networks, Pearson Prentice Press, Upper Saddle River, NJ, 2004 Newman, M.C and Evans, D .A. , Enhancing belief during causality assessments: Cognitive idols or Bayes’s theorem? In Coastal and Estuarine Risk Assessment, Newman, M.C., Roberts, M.H., Jr., and Hale, R.C., (eds.), CRC Press, Boca Raton, FL, 2002, pp 73–96 Newman, M.C., Zhao, Y., and Carriger, J.F., Coastal and estuarine ecological... Regional resource managers and politicians asked scientists to determine the cause so a remedy could be found Early in the process, the notionally toxic dinoflagellate Pfiesteria piscicida was identified as the cause by North Carolina researchers (e.g., Burkholder et al 1992) This conclusion leaned heavily on statements like the one quoted above The basis for this statement was 3 years of monitoring data... piscicida were found at 8 of 15, 5 of 8, and 4 of 10 large fish kills When counterarguments were presented that episodic low oxygen events could be the cause, a confrontation took place that “became mired in accusations of ethical misconduct, risk exaggeration, and legislative stonewalling” (Newman et al 2007) The maladaptive features of heterophilic exchange manifested, leading to the resource managers . An example of applying Bayesian inference using natural frequen- cies. Probabilitiesareplacedalongsidearrows associated with different states. The num- bers associated with each branch are based on. Models Data Analy., 5, 53–76, 1989. Lane, D .A. , Kramer, M.S., Hutchinson, T .A. , Jones, J.K., and Naranjo, C., The causality assessment of adverse drug reactions using a Bayesian approach, Pharmaceut piscicida was implicated as the causative agent of 52±7% of the major fish kills on an annual basis in North Carolina estuaries and coastal waters. (Burkholder et al. 1995) A series of large fish