Reviewer #1 (Public Review):
In this paper, Jan Kubanek attempts to derive an 'effective decision strategy' that is optimal (and therefore normative) given certain constraints resulting from computational capacity limitations. The author first points out that neoclassical economics (i.e., expected utility theory, EUT) provides normative predictions for decisions to maximize utility. Next, he (correctly) points out that finding the optimal solutions to decision problems requires computational resources that are unlikely to exist in actually existing decision-makers (animals and humans). He claims that this fact is the most severe problem for concluding that EUT is an accurate description of actual human or animal decision processes. I disagree with him on this point as I will lay out in more detail below. Next, the author attempts to find an 'efficient' (i.e., computationally reasonable) decision strategy that comes close to the original normative framework. He claims that such a strategy is EDM, whereby decisions are made by allocating relative effort in proportion to the relative reward of each option.
Overall, I find this paper hard to judge. The considerations described in this paper are certainly interesting and I have no reason to presume that the mathematical derivations described are wrong (without having made an effort to follow and check it in detail). Still, I find the paper, in the end, sterile and I fear it will have only limited impact. I think the manuscript should be expanded in three different directions to make it more relevant for the neuroscientific understanding of decision making. First, the author needs to show that EDM can also explain other known violations of EUT related to the axiom of regularity (i.e., preferences between two options should not be affected by the presence of inferior options). This seems relevant because these behavioral effects robustly violate the choice allocation strategy of EDM. Second, EDM is so abstract that the actual structure and capacity of the nervous system are nearly irrelevant. The author should consider more deeply the computational requirements and capacities of different types of brains; fruit flies, frogs, and primates, and the consequences of these differences for what is (or should be) achievable in terms of optimal behavior. Third, the paper contains no test for EDM. This is in part because EDM is at no point compared to the predictions of alternative theories.
My specific concerns are as follows:
(1) The author claims that the most severe problem of EUT is that it is computationally implausible. However, I disagree. It could be claimed that EUT describes an (unattainable) optimal state that actual brains try to accomplish with limited resources. (In essence, the current paper follows this strategy). I think the situation is much direr. During the last 70 years, a small army of psychologists and behavioral economists have described a large number of violations of EUT's normative predictions: the Allais paradox, framing effects, the behavioral tendencies summarized in Prospect theory, and others. These differences between behavior and normative predictions are important because they violate basic assumptions of the normative theory.
(2) The most interesting case of such violations is a set of well-known behavioral effects that occur in the context of multi alternative-multi attribute decision making. They are known as the attraction, similarity, and compromise effects (there is a large literature; more recently: Dumbalska T, Li V, Tsetsos K, Summerfield C. A map of decoy influence in human multi alternative choice. Proc Natl Acad Sci U S A. 2020 Oct 6;117(40):25169-25178. doi: 10.1073/pnas.2005058117. Epub 2020 Sep 21.) These biases have received so much attention because they violate a very basic axiom of EUT. Choices between two options should not be affected by the presence of a third option that is inferior to both of them. However, that is exactly what happens in these choice biases. The effects have been shown in many species ranging from humans to amphibians to invertebrates. As far as I can see, EDM cannot explain how choice allocation between two options A and B that have equal value would be changed by the inclusion of a new option D so that is of lower value than A or B in such a way that D is not chosen at all, but A is chosen more often than B if D is similar in attributes to A (the 'attraction' effect). If I am mistaken, the inclusion of an explanation of how this would work would be of major importance.
(3) EDM as described in this manuscript is completely static, that is it ignores actual computational processes that underlie decision making. This is in opposition to an important modern branch of decision research that has stressed the importance of understanding processes (and their limitations) to understand how choices are made. Examples are: (1) Roe RM, Busemeyer JR, Townsend JT. Multialternative decision field theory: a dynamic connectionist model of decision making. Psychol Rev. 2001 Apr;108(2):370-92. doi: 10.1037/0033-295x.108.2.370. PMID: 11381834.; (2) Tsetsos K, Usher M, Chater N. Preference reversal in multiattribute choice. Psychol Rev. 2010 Oct;117(4):1275-93. doi: 10.1037/a0020580. PMID: 21038979. The relationship between EDM and algorithmic implementations should be explored.
(4) Most importantly, what is missing is a clear prediction for a finding (behavioral or neuronal) that would only be predicted, but not by any other theory of decision making. Without such a proposed test, the idea has no scientific merit.