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Gigerenzer on logical rationality vs. ecological rationality

I sent my post about the political implication of behavioral economics, embodied cognition, etc., to Gerd Gigerenzer, who commented as follows:

The “half-empty” versus “half-full” explanation of the differences between Kahneman and us misses the essential point: the difference is about the nature of the glass of rationality, not the level of the water. For Kahneman, rationality is logical rationality, defined as some content-free law of logic or probability; for us, it is ecological rationality, loosely speaking, the match between a heuristic and its environment. For ecological rationality, taking into account contextual cues (the environment) is the very essence of rationality, for Kahneman it is a deviation from a logical norm and thus, a deviation from rationality. In Kahneman’s philosophy, simple heuristics could never predict better than rational models; in our research we have shown systematic less-is-more effects.

Gigerenzer pointed to his paper with Henry Brighton, “Homo Heuristicus: Why Biased Minds Make Better Inferences,” and then he continued:

Please also note that Kahneman and his followers accept rational choice theory as the norm for behavior, and so does almost all of behavioral economics. They put the blame on people, not the model.

This makes sense, in particular the less-is-more idea seems like a good framing.

That said, I think some of the power of Kahneman and Tversky’s cognitive illusions, as with the visual illusions with which we are all familiar, is that there often is a shock of recognition, when we realize that our intuitive, “heuristic,” response is revealed, upon deeper reflection, to be incorrect.

To put it in Gigerenzer’s framework, our environment is constantly changing, and we spend much of our time in an environment that is much different than the savanna where our ancestors spent so many thousands of years.

From this perspective, rational choice is not an absolute baseline of correctness but in many ways it works well in our modern society which includes written records, liquid and storable money, and various other features for which rationality is well adapted.


  1. Keith O'Rourke says:

    Interesting – we did have a reference [Driver, M. J., and Streufert, S. (1969)] for less-is-more here

    “[the real is] that whose characters are independent of what anybody may think them to be”

    “[the real is encountered in experience as opposition] a conception which we must first have had when we discovered that there was an unreal, an illusion; that is, when we first corrected ourselves”

    Guess who? ;-)

  2. Fernando says:

    Reminds me of evolutionary game theory.

    Take your pick. Humans are:

    1. “a sort of particle in the water being jostled by invisible Brownian forces” (AG)
    2. “a bot with hardwired responses to stimuli (so-called decision functions), only some of which lead to survival and procreation”
    3. “creatures of God with independent agency” (Ok no need to appeal to God, but then we have to reconcile free will with determinism)

    I think the issue is really about determinism versus agency. Maybe even about duality of mind and body, and (dare I say it) the existence of a soul. And since we are now in so-called crackpot land, about AI and singularity.

  3. Kyle C says:

    Prof, wanted to alert uou your main website seems to be down and I can only get in

  4. Dale Lehman says:

    Interesting and valuable article. But I keep feeling that the Gigerenzer – Kahneman debate is an academic testosterone match. Heuristics are clearly necessary for life but that does not mean that all heuristics work well. I think Kahneman’s work shows that many are dysfunctional. Biology has adapted us to use heuristics but the types of decision problems we face are increasingly out of synch with biology and evolution. So, heuristics like choosing a winner based on two examples might have worked when hunting wooly mammoths, but don’t appear to be good ways to pick stocks.

    • Andrew says:


      I don’t know that much is gained via gendered expressions such as catfight or testosterone match. I prefer to think of this as a healthy scientific discussion, and I’m glad that people with different perspectives can discuss their differences openly!

      • Diogo Cao says:

        It’s even worse to buy into the demented oppressive straightjacket of Cultural Marxism. Long live to expressions like “catfight” and “testosterone match” as long as we can end the never-ending stream of male guilt-tripping. To put it more clear: you won’t end with the demonization of males by buying the principles of the ones pushing it to everybody. I agree on the main point: it’s a healthy scientific discussion, but please, nothing is gained by emasculating everybody in sight according to the ideological madness of SJW’s. A little bit of freedom, just for a change.

        • Andrew says:


          To call something a “testosterone match” just because the parties happen to be men, seems pointless and inaccurate to me. Why not just call it a scientific dispute? This has nothing to do with Marxism or SJF’s or freedom or democracy or whatever. I don’t see anything particularly male or testosterony about the disagreements between Tversky, Kahneman, and Gigerenzer. They just have different perspectives, all of which I find valuable.

    • Elrod says:

      It is also worthwhile noting where our deficits are. For example, the following article by Gierenzer (and Klaus Hug):
      corroborated evidence that we are generally very bad at evaluating the validity of “if, then” statements – except when the possibility that we’re being cheated exists. In that case, our accuracy roughly jumps from 40% to 90% (based on students enrolled in Konstanz university). 90% still sounds rather low for mathematically simple problems, but it is a lot better than 40%.
      This conforms with evolutionary psychology: when it can actually help us, we’re suddenly rational. Otherwise, who cares? Most of us still do consciously (probably), so we can play the role of good guy while blissfully ignorant of those around us being cheated — even if we’re the cheaters milking an advantage — due to our own failed “rationality”.
      By this metric of success, our biases are more rational than having an accurate picture of reality.
      This is why imagining things from other’s perspectives is so powerful in helping us empathize. And it even makes sense to us that it should help, even though we obviously already have all the information needed to compute the decisions and evaluate value functions.

      Thankfully our conscious minds honestly believe we want the greater good, so we/they can fight back by studying biases and statistics – or at least making the effort to imagine things from other’s perspectives.
      The sorts of issues Dr. Gelman has complained about with Psychological Science strike me as fitting into this mold.

    • Rahul says:


      This sounds like academic nit picking to me.

  5. Berglund says:

    > “And since we are now in so-called crackpot land…”

    Yes, all this stuff inevitably & rationally leads to the quite uncomfortable ‘crackpot’ fundamental — epistemology.
    How does one “know” anything ?

    What is the basic relationship between man’s mind and reality ?
    Any cognitive method rests totally upon epistemology. If you haven’t nailed down your epistemological premises … then you have no basis to seriously discuss such subsidiary issues of rationality, science, determinism, duality, etc.

  6. It is unfortunate that both Gigerenzer and Tversky/Kahneman use the same term “heuristics”.

    In the Tversky/Kahneman world, a heuristic decision rule we find by:

    a) constructing a word problem of a logical or statistical puzzle,
    b) seeing that most people don’t solve the underlying logical or statistical puzzle.

    But instead most use this heuristic to solve the word problem.

    It would be as if some algebra problems when recast as word problem resists mathematical solutions.

    In the Gigerenzer world, a heuristic is a decision rule we find by seeing;

    a) that some relatively simple rules work better more complicated rules.
    b) or, that even complicated decision rules need to be made simple in order to be communicated effectively.

    There is an unfortunate tendency to think that “heuristic” has the same meaning for both scientists.

  7. From the paper quoted:

    “For instance, Tversky (1972, p. 98) concluded that elimination-by-aspects ‘‘cannot be defended as a rational procedure of choice.’’ More outspokenly, two eminent decision theorists, Keeney and Raiffa (1993), asserted that reliance on lexicographic heuristics ‘‘is more widely adopted in practice than it deserves to be,’’ and they stressed that ‘‘it is our belief that, leaving aside ‘administrative ease,’ it is rarely appropriate’’ and ‘‘will rarely pass a test of reasonableness’’ (pp. 77–78).”

    Gigerenzer is probably correct when he claims “Contrary to the belief in a general accuracy-effort tradeoff, less information and computation can actually lead to higher accuracy, and in these situations the mind does not need to make trade-offs. Here, a less-is-more effect holds.”

    I think that we should expect to get a better formalization of a fast and frugal rule, and how such rules deal with less information and computation in order to roughly right.

    It would not surprise me if this turned out to be an extension of our current rational choice model.

  8. Krzys says:

    I think the ecological qualifier is a bit misleading here. The question is not of biological adaptation, but the fundamental properties of optimal rules in small samples: in other words the variance-bias decomposition. The “rational” framework assumes the knowledge of the DGP and solve for the optimal rule, however in small samples, the estimated model will overfit. Consequently, a biased rule (with lower variance) will outperform. It’s a math issue. In other words, rules with the greatest fit to data are strictly speaking irrational, as is Khaneman’s critique.

  9. Klaus Hofmann says:

    If only Lao Tzu were here to advise, with his usual clarity. My guess is collaboration; setting aside individual convictions, for now, to see what may have been missed.
    Both are pursuing the same goal, both are brilliant – so, give some additional/different perspectives your sincere and collaborative effort. (Time is also a factor !)

  10. Klaus Hofmann says:

    Clearly this site is a waste of anyone’s time.

  11. Glen M. Sizemore says:

    I only have a little to say…

    Alas…this is what happens when (as is usually the case) the natural science of behavior and its philosophy are ignored (thanks to the de facto censorship by mainstream psychologists wrought by a half-wit linguist and folk-psychology). Here is how the discussion should proceed:

    Contingency-shaped behavior – think the prototypical “Skinner-box” experiment (Fred Skinner hated that term, BTW…it’s called an “operant chamber”). There is a contingency (dependency…but it’s complicated and I’m trying to be my usual short-winded self) between lever-pressing and the delivery of a food-pellet and, consequently, the rat comes to press the lever a great deal and does other stuff a lot less. That is contingency-shaped behavior.

    Rule-governed behavior – I could say to a human “Pressing that switch sometimes results in the delivery of a dollar. Your dollar count is shown in the window at the top-right corner of the panel” and the human would come to press the switch a great deal and do other stuff a lot less. This behavior did not come from nowhere and it did not spring from the alleged mind. It also came from (a *whole bunch* of) contingencies – but not a specific contingency between switch-pressing and dollar delivery in the same sense of the contingency between lever-pressing and food-delivery in the rat example. Of course, once the human begins to respond, he or she is then exposed to a specific contingency (but the effects of the contingency may depend on whatever rule-governed behavior emerged first). This is, in fact, how much skilled behavior is acquired: instruction (taking advantage of the person’s verbal behavior and his or her history of following rules, i.e., a *whole bunch* of contingencies – IOW, rule-governed behavior) produces the initial responses, but the skilled behavior emerges when *that* rule-governed behavior “directly contacts” contingencies that “turn the rule-governed behavior into contingency-shaped behavior”).

    Although the behavior of the human in the above simple example would *resemble* that of the rat (under certain circumstances), the distinction (as well as the similarities) between the classes of response is, you know, like *really* important. The distinction between contingency-shaped and rule-governed behavior is the natural science version of the bush-beating that are discussions of rationality vs.empiricism, Gigerenzer vs. Kahneman, logic vs. heuristics etc. etc. etc.

    Hope this helps…call me magnanimous…and humble…

    Uncle Glen, Ph.D., ne’er-do-well retired professional scientist and International Man of Mystery

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