Great but elusive question. Depends on what is meant with a homo behavioralis. See e.g. http://www.bloombergview.com/articles/2015-06-01/a-dose-of-psychology-does-economics-field-some-good and follow the in-text hyperlink to http://www.psychologicalscience.org/index.php/publications/observer/2009/february-09/surrogates-for-theory.html by my favorite cognitive psychologist. Building on Gigerenzer I would say that homo behavioralis (just like homo economicus) does not exist. It is the latest straw man used to push whatever agenda you want, depending on the bias you select and the bias you ignore.

The best model of a human being for the law maker is no model.

While taking into account the outcome of different relevant models in big data analysis and simulations, the law maker should address pressing issues based on taking people seriously as underdetermined individuals that change course despite the statistics.

Instead of modeling the humans that should be the vanishing point of the analysis, check - for instance - the capability approach as a means to guide lawmaking. 

Dear Radoslaw,

your question in the title does not seem to fit the question you pose at the end of the explanatory paragraph. I gather your real question is the second one (although it is also interesting to ask how we should conceptualise the lawmaker herself). ANd I appreciate your effort to soften the rough edges of the homo economicus model. I think for this reason it is much more suitable as a "good lamaker's model). But I agree with Mireille not to turn the plebs into a facelss mob or statistical avaerage. On the other hand I do think there is such a thing as a "common good", and to enquire what it consist of I prefer to look into the ideas of Aristotle and Aquinas.

Best,

Ferenc

A generic construct of homo behavioralis is not very useful. Instead, we need an identification of the specific types of bounded rationality that the particular individuals and institutions regulated by the law being considered exhibit. For example, economic regulation should take into account the tendency of investors and Wall Street to get exuberant during upswings and panic in down markets. I've spelled this out in The Economic Dynamics of Law (Cambridge U. Press 2012) with examples.

Dear Mireille,

Thank you very much for your answer. I like very much this line “The best model of a human being for the law maker is no model.” As an academic I agree with you, but as a lawyer I have objections.

Lawyers, states officials, judges and lawmakers assume a certain picture of human nature and decision making model. This is a fact. They need it when they make decisions relevant from legal perspective. When it comes to polish legal system, the picture and the model are very similar to one developed by German legal philosopher Gustav Ihering. Ihering’s vision on human nature is simplistic, out-of-date and in some aspects similar to homo economicus. Therefore, more often than not, he is present in day-to-day operations, during solving disputes, enacting a new law and so on. The question is how to change this underlying assumption, having in mind, that the law is practical in sense: whatever works, works.

Telling practical-minded lawyers/lawmakers that they need to take under consideration the shortcomings of human nature will not suffice, because they have no time or will to change anything. Therefore, I wonder whether homo behavioralis can serve as good as homo economicus when it comes to making a new law, because it is more complex, more elusive, and, in its generic version, provides limited predictions. Although, it has more in common with reality of human decision-making, than homo economicus.

Dear Ferenc,

One of my professors said once that the Constitution should have only one norm: „bonum est faciendum, malum vitandum”, because other legal and philosophical issues are secondary. So if you suggest that we should pay more attention to the values implemented by the law and realized by it I agree with you. And yet law in modern society is a complex, powerful tool used by lawmaker. For example, in Poland in 2014 almost 25 000 pages of new law were "produced". I like to think that lawmaker uses an up-to-date model of human nature, than he's stuck with the contractual one.

Dear David,

If I understand you correctly, you agree with the thesis that behavioral economics or cognitive psychology should be used by a lawmaker during enacting new law. Especially, when it comes to cognitive biases or other consequences of bounded rationality, willpower and self-interest (i.e. risk aversion, endowment effect, hindsight bias). And yet generic version of homo behavioral is no good for lawmaker’s purposes?

 However,  lawmakers need general guidelines (homo economicus provides such guidelines), therefore maybe, for practical reasons, homo economicus will survive in legal environment, because it is more simple, elegant, and provide some kind of (easy assimilable) knowledge about human motivations, reason and decision-making processes? Maybe, homo behavioralis in generic version is too vague, and in more detailed version is too complex?

This is an interesting question. Assuming bounded rationality models of human judgment and decision become dominant, then the ethical question is: can a law maker be a responsible law maker while ignoring the reality of human nature? What would be the ethical basis for justifying the use of a simplified or outdated understanding of the human mind while producing laws for actual people?

I would say that, unless the practice of law making turns out to be impossible or outrageously costly when based on the current understanding of the mind, or unless the benefits of that approach turn out to be marginal at best by contrast with other approximations (which must still pass some 'acceptabiity' bar), then there is no such excuse. 

As a side note, there might well be no such a thing as a "no model" of human mind in the practice of law making. However one chooses to approach the design of a binding rule for others (and unless one casts dice of course) an implicit theory of what motivates people to act and judge will come into play. Standard or common models (including classic economic theory) do not constitute a "no model" just because we take them for granted or use them as a matter of course. Even what psychologists term "lay psychology" still constitutes a model (albeit a loose one). The burden of informed choice might be inescapable.

Dear Radoslaw:

Lawmakers sometimes do take more specific models into account, although often unconsciously. This occurs quite often when administrative agencies make law, because they usually have some familiarity with the behavior of the entities or individuals they regulate. I would argue that an implicit behavioral model of finance along the lines I've indicated informed post-depression financial regulation in the United States in the 1930s, not to mention Keynsian economics. Assuming rationality is dangerously misleading, as we learned when we laid the groundwork of the financial crisis of 2008 through deregulation based on rational actor models. Assuming bounded rationality is useless, unless something is assumed about what the bounds of the rationality look like for particular institutions and actors. What incentives do particular types of regulated parties pay attention to and which do they overlook?  Again, my Economic Dynamics of Law book spells out how to do this and argues that this what policymakers did when they saved the financial system through bailouts.

Dear Radoslaw, 

Gustav Jhering seems to be an integration of Rudolf von Jhering and Gustav Radbruch. The former critiqued the formalistic positivism of his former self and became more sociologically minded. This is always a bit dangerous because it tends to turn lawyers into policy makers, suggesting the law is a means to manipulate people into behaving in a certain way. Law is both more and less. Radbruch, however, is still very relevant today, he had a keen eye for the competing goals and values of the law. 

Check out 'Heuristics and the Law', an excellent collection of articles on the subject of your question: https://mitpress.mit.edu/books/heuristics-and-law.  Edited by Gigerenzer, who I think is far more sophisticated than Kahenmann. We don't want to delude the lawmaker with supposedly 'scientific' models; better to help the lawmaker to make sure eventual models are contestable. Making laws is - in a democracy - the task of politicians. Making laws contestable is - in a Rechtsstaat - the task of the lawyers.

Mireille