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Human Nature Review 2002 Volume 2: 548-550 ( 12 December )
URL of this document http://human-nature.com/nibbs/02/thinking.html
Adaptive Thinking: Rationality in the Real World
By Gerd Gigerenzer
Oxford University Press, New York, 2000
Reviewed by Lisa Bortolotti, Philosophy Program, RSSS, Coombs Building, ANU, Canberra ACT 0200, Australia.
This collection includes the most influential papers written by Gigerenzer on rationality. The chapters are updated versions of previously published papers, divided in five sections and arranged in a way that shows the systematicity and convergence of Gigerenzer's philosophical interests. The style of writing is accessible and engaging, and the papers are a valuable contribution to the contemporary literature on human rational thinking. Anyone fascinated by the way in which our minds work, and especially philosophers and psychologists, will find this a rewarding read.
The underlying project consists in attempting to undermine the traditional gaps between both normative theories of reasoning and descriptive ones, and the context of justification and the context of discovery. The take-home message is that these dichotomies are misleading, as they are founded on the questionable assumption that the standards for correct human reasoning come from logic, statistics, probability and decision theory and that our actual reasoning performance cannot but fail to conform to such standards. Gigerenzer wants to develop an alternative view of human rationality and scientific methodology that is sensitive to the important relation between human agents and the natural and social environment in which they operate.
This revisionist project starts from the observation that the strategies we actually use when we make choices and solve problems do not need to be seen as unreliable and inaccurate, but rather as the valuable product of selection. Heuristics do yield good results when they are used in the appropriate context. If it is true that we can trust heuristics, then we might not need more computationally expensive ways to learn about the complex and uncertain world in which we live.
Here is the structure of the book. In the first section, Gigerenzer introduces and discusses the tools-to-theories heuristic, based on the idea that sometimes "new insights can come from outside the mind" (p. 1). According to this heuristic of discovery, some of the tools we use in scientific practice suggest metaphors and concepts that then become part of our theories. One striking example is our use of computers. The computer has become a metaphor of the mind and this metaphor has informed psychological and philosophical theories of the mind. From Turing's conception of computers as 'thinking machines', new theories of how the mind works have developed and this has been signalled by the adoption of a new terminology (for instance, we talk now about 'computational costs' with reference to our limited cognitive capacities).
In the second section, on ecological rationality, Gigerenzer explores the relation between the mind and people's natural environment - past, present and future. In particular, he compares ways of representing probabilistic information and discusses the limits and strengths of human inference under uncertainty.
In the third section he introduces Herbert Simon's notion of bounded rationality and develops it in an original way. How can we make effective decisions in the real world, where time is scarce, our resources are limited and we are always in a condition of partial ignorance? According to Gigerenzer, we manage to make choices and solve problems by adopting some simple heuristics that fit the structure of the environment in which we live and the kind of choice or task with which we are faced.
Here is one example of these heuristics at work. Suppose you are asked which of two cities (a or b) is more populated. The recognition heuristic tells you to choose the object you recognise. If you have heard of a but not of b, then you should say 'a'. But, if you haven't heard of either, or you have heard of both, the Take the Best heuristic tells you to rank some cues and compare a and b according to those cues. As soon as one city has a positive value and the other has a negative one with respect to one cue, the search stops and a decision is made. Suppose a is larger than b. Then you should choose a as the most populated city. The idea is that, when we lack information, we tend to ascribe positive value to objects that we easily recognise (recognition) and we stop searching when the highest ranking cue discriminates between the objects (Take the Best). Gigerenzer convincingly argues that in cases of partial ignorance this is a very successful procedure.
In the fourth section Gigerenzer discusses issues of social rationality, which is just a special kind of ecological rationality. The focus here is the relation with the environment constituted of conspecifics. In the social environment, individual deliberation is only part of the picture. Phenomena such as imitation and cheater detection become important and contribute significantly to decision making and problem solving.
In the last section of the book, on cognitive illusions, Gigerenzer revisits the 'rationality wars', the heated debate in cognitive science about the significance of systematic reasoning mistakes. The question Gigerenzer wants to ask is whether apparent violations of normative standards are an indication of irrationality. Gigerenzer criticises the choice of standards of reasoning that psychologists have taken for granted and challenges the basis of the 'heuristics-and-biases' hypothesis. He claims that our reliance on pragmatic strategies is what makes us successful decision-makers and problem solvers in the real world, and does not necessarily lead to making 'mistakes'.
The notion of ecological and bounded rationality is not fully developed yet, and it is difficult to assess its role as a normative theory of rationality. Gigerenzer provides a satisfactory account of the strategies that we use in real-life situations. He is right in insisting that such strategies are not always misleading and argues convincingly that they have been selected because they are largely successful in some specific contexts. But when it comes to providing a normative theory of reasoning, rather than a merely descriptive one, a justification for the normativity of the standards must be provided too. It is of course possible to have accurate strategies that describe accurately the way in which we reason and that play a normative role, but it is hard to see what this means in the case of the heuristics Gigerenzer advocates.
Within the heuristics-based model, a reasoning output in the context of a specific task is rational if it has been obtained by following a strategy that is feasible and largely successful when applied to that task. But what helps us discriminate between strategies that deserve the special status of normative standards and those that don't? If the fact that the strategies have been selected were already a sign of their reliability and accuracy, we should grant all of them a normative status, when they are applied in the relevant contexts. Then, as a consequence of this picture, our reasoning would turn out to be all-normative. The way in which we reason would be the correct one by default, because it has passed the test of natural selection. This conclusion would be equivalent to regarding most of human reasoning outputs as rational and would not serve the purpose that a normative theory of rationality is supposed to serve, that is, provide criteria for discrimination between rational and non-rational strategies and behaviour.
In spite of my doubts about the philosophical sophistication of Gigerenzer's work, his project has the potential to become a truly revolutionary approach to rationality. Gigerenzer is not alone in urging us to take seriously the adaptive nature of human reasoning, but he is one of the few who has the courage to envisage an entire new framework. He argues persuasively that we should be looking for normative standards of human reasoning that are shaped by the relation between the mind and the environment, and reflect the only kind of rationality that matters to us, the rationality that allows limited systems to control a complex and ever-changing world. What these standards exactly are, and why they play a normative role, are questions yet to be answered.
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© Lisa Bortolotti.
Bortolotti, L. (2002). Review of Adaptive Thinking: Rationality in the Real World by Gerd Gigerenzer. Human Nature Review. 2: 548-550.