Maestripieri et al. review cross-disciplinary approaches to understanding why we bias prosocial behavior toward attractive people. Their review should bring evolutionary psychology (EP) studies to the attention of social scientists while enlightening EP studies with a fuller appreciation of what has been done in the social sciences. However, in advancing the cause of adaptation as an explanation for prosocial biases, the treatment of EP here lacks a conceptual framework and critique. I therefore provide comments on the evolutionary approach presented.
Regarding their conceptual framework, Maestripieri et al. consider “mating motives” as central to the evolutionary approach. Aside from this being an unfortunate term in invoking proximate mechanisms rather than adaptation, this is not a term used in EP. When discussing prosocial biases in favor of attractive people, evolutionary psychologists invoke sexual selection, the process of evolutionary change resulting from mating competition (Darwin Reference Darwin1871). It is notable that sexual selection is not referred to at all in the review, so the theoretical basis of the article must be considered weak.
Related to this, Maestripieri et al. present what they say are three different evolutionary explanations. The first they call the “functional evolutionary hypothesis” (despite all evolutionary hypotheses being about function). This theory apparently holds that prosocial behavior toward attractive people “maintains proximity.” It assumes that prosocial behavior toward attractive people is deeply engrained in the human mind. Yet this simply begs the question of why prosocial behavior is engrained in the human mind. The second, referred to as a “non-functional hypothesis,” turns out to be a misunderstanding of how adaptation works on characteristics that are on average beneficial. Both are therefore in fact corollaries of their third hypothesis, which they refer to as the “sexual signaling hypothesis.”
Here we are getting closer to evolutionary psychology where it is established that helpfulness, generosity, kindness, and altruism serve as courtship displays. Nevertheless, Maestripieri et al. fail to say anything about why helpfulness may be used as a courtship display as opposed to other behaviors. To do so, one has to invoke signaling theory: What is being signaled by prosocial behavior (Maynard Smith & Harper Reference Maynard Smith and Harper2003; Roberts Reference Roberts1998)? Is it a costly signal demonstrating honestly that one has a high level of resources (Gintis et al. Reference Gintis, Smith and Bowles2001)? Is it a reliable signal of future prosocial behavior? What makes someone attractive? Do signal receivers (attractive individuals) benefit directly through increased resources from the partner or indirectly from the “good genes” of a partner? These are all key to understanding the notion that individuals are more prosocial to attractive people. Otherwise, concluding that “attractiveness has intrinsic value (because attractive people have high mate value)” (sect. 4.1, para. 8) tells us no more than that we want to mate with attractive people.
There are too many misunderstandings to mention here. For example, Maestripieri et al. say that a “preference for attractive individuals … may not in itself increase an individual's biological fitness” (sect. 2.1.3, para. 2), whereas in reality such a preference should have on average increased fitness, hence the preference persists. Also, they misrepresent as reciprocity the case of signaling to sexual partners through prosocial behavior and then benefiting through mating. In fact, prosocial behavior benefits the signaler because it persuades the attractive individual to mate, while benefiting the attractive individual who gets a high-quality mate. Another example is the repeated conflation of function and mechanism. For example, they say there is an incentive to invest in attractive people, then “moreover” that the human mind is predisposed to respond to cues of mating – the second simply being a proximate consequence of the ultimate explanation.
Maestripieri conclude with a call for recognition of functional explanations to complement mechanistic ones. A similar conclusion was reached by Tinbergen (Reference Tinbergen1951), so it should not be necessary to repeat this. Sadly, this call does remain valid among those not yet enlightened by evolutionary thought (Darwin Reference Darwin1859). Basic misconceptions seem rife at the highest level among economists working on prosocial behavior: misunderstanding the role of evolutionary theory in generating hypotheses; claiming behavior is not adaptive, then using terms such as “other regarding preferences” as if these were explanatory; presenting descriptions of behavior (e.g., strong reciprocity) as if that were an alternative to functional explanation; not appreciating the role of “ultimate” explanation; and being “baffled” about phenomena that are well understood by others. Perhaps this is in part because economists are trying to exclude everything outside a game structure as confounding factors. In fact, reputation (Roberts Reference Roberts1998), specifically here in a mate choice context, may be among the most interesting factors.
Hence, this article is welcome if it helps to raise the profile of “sexual signaling” as a serious explanation for prosocial behavior alongside concepts such as reciprocity. Unfortunately, sexual selection is still looked down upon by some as a potential explanation for human cooperation, yet to evolutionary biologists, familiar with the power of sexual selection in producing the most extraordinary structures and behaviors in the natural world, it comes as no surprise that it should also be involved in prosocial behavior. There is a paradox that if one were to say to the average person that men will be more helpful toward more attractive women, then the person would say it was just common knowledge.
Nevertheless, the article should be doing more to show a way forward. For example, studies should test when we should find a bigger effect of attractiveness on men's behavior than on women's and when it should be similar, based on the relative strength of sexual selection in men and women (Stewart-Williams & Thomas Reference Stewart-Williams and Thomas2013). Studies should also examine theoretically and empirically what is being signaled by prosocial behavior and what benefits signalers and receivers get. Section 3.2.2 lists and tabulates some EP studies, but we need a critical review of these in terms of procedural details (Farrelly et al. Reference Farrelly, Lazarus and Roberts2007). Studies should also consider the role of competition for potential partners and when we predict the greatest prosocial behavior toward attractive people will occur (Raihani & Smith Reference Raihani and Smith2015; Roberts Reference Roberts2015).
Maestripieri et al. review cross-disciplinary approaches to understanding why we bias prosocial behavior toward attractive people. Their review should bring evolutionary psychology (EP) studies to the attention of social scientists while enlightening EP studies with a fuller appreciation of what has been done in the social sciences. However, in advancing the cause of adaptation as an explanation for prosocial biases, the treatment of EP here lacks a conceptual framework and critique. I therefore provide comments on the evolutionary approach presented.
Regarding their conceptual framework, Maestripieri et al. consider “mating motives” as central to the evolutionary approach. Aside from this being an unfortunate term in invoking proximate mechanisms rather than adaptation, this is not a term used in EP. When discussing prosocial biases in favor of attractive people, evolutionary psychologists invoke sexual selection, the process of evolutionary change resulting from mating competition (Darwin Reference Darwin1871). It is notable that sexual selection is not referred to at all in the review, so the theoretical basis of the article must be considered weak.
Related to this, Maestripieri et al. present what they say are three different evolutionary explanations. The first they call the “functional evolutionary hypothesis” (despite all evolutionary hypotheses being about function). This theory apparently holds that prosocial behavior toward attractive people “maintains proximity.” It assumes that prosocial behavior toward attractive people is deeply engrained in the human mind. Yet this simply begs the question of why prosocial behavior is engrained in the human mind. The second, referred to as a “non-functional hypothesis,” turns out to be a misunderstanding of how adaptation works on characteristics that are on average beneficial. Both are therefore in fact corollaries of their third hypothesis, which they refer to as the “sexual signaling hypothesis.”
Here we are getting closer to evolutionary psychology where it is established that helpfulness, generosity, kindness, and altruism serve as courtship displays. Nevertheless, Maestripieri et al. fail to say anything about why helpfulness may be used as a courtship display as opposed to other behaviors. To do so, one has to invoke signaling theory: What is being signaled by prosocial behavior (Maynard Smith & Harper Reference Maynard Smith and Harper2003; Roberts Reference Roberts1998)? Is it a costly signal demonstrating honestly that one has a high level of resources (Gintis et al. Reference Gintis, Smith and Bowles2001)? Is it a reliable signal of future prosocial behavior? What makes someone attractive? Do signal receivers (attractive individuals) benefit directly through increased resources from the partner or indirectly from the “good genes” of a partner? These are all key to understanding the notion that individuals are more prosocial to attractive people. Otherwise, concluding that “attractiveness has intrinsic value (because attractive people have high mate value)” (sect. 4.1, para. 8) tells us no more than that we want to mate with attractive people.
There are too many misunderstandings to mention here. For example, Maestripieri et al. say that a “preference for attractive individuals … may not in itself increase an individual's biological fitness” (sect. 2.1.3, para. 2), whereas in reality such a preference should have on average increased fitness, hence the preference persists. Also, they misrepresent as reciprocity the case of signaling to sexual partners through prosocial behavior and then benefiting through mating. In fact, prosocial behavior benefits the signaler because it persuades the attractive individual to mate, while benefiting the attractive individual who gets a high-quality mate. Another example is the repeated conflation of function and mechanism. For example, they say there is an incentive to invest in attractive people, then “moreover” that the human mind is predisposed to respond to cues of mating – the second simply being a proximate consequence of the ultimate explanation.
Maestripieri conclude with a call for recognition of functional explanations to complement mechanistic ones. A similar conclusion was reached by Tinbergen (Reference Tinbergen1951), so it should not be necessary to repeat this. Sadly, this call does remain valid among those not yet enlightened by evolutionary thought (Darwin Reference Darwin1859). Basic misconceptions seem rife at the highest level among economists working on prosocial behavior: misunderstanding the role of evolutionary theory in generating hypotheses; claiming behavior is not adaptive, then using terms such as “other regarding preferences” as if these were explanatory; presenting descriptions of behavior (e.g., strong reciprocity) as if that were an alternative to functional explanation; not appreciating the role of “ultimate” explanation; and being “baffled” about phenomena that are well understood by others. Perhaps this is in part because economists are trying to exclude everything outside a game structure as confounding factors. In fact, reputation (Roberts Reference Roberts1998), specifically here in a mate choice context, may be among the most interesting factors.
Hence, this article is welcome if it helps to raise the profile of “sexual signaling” as a serious explanation for prosocial behavior alongside concepts such as reciprocity. Unfortunately, sexual selection is still looked down upon by some as a potential explanation for human cooperation, yet to evolutionary biologists, familiar with the power of sexual selection in producing the most extraordinary structures and behaviors in the natural world, it comes as no surprise that it should also be involved in prosocial behavior. There is a paradox that if one were to say to the average person that men will be more helpful toward more attractive women, then the person would say it was just common knowledge.
Nevertheless, the article should be doing more to show a way forward. For example, studies should test when we should find a bigger effect of attractiveness on men's behavior than on women's and when it should be similar, based on the relative strength of sexual selection in men and women (Stewart-Williams & Thomas Reference Stewart-Williams and Thomas2013). Studies should also examine theoretically and empirically what is being signaled by prosocial behavior and what benefits signalers and receivers get. Section 3.2.2 lists and tabulates some EP studies, but we need a critical review of these in terms of procedural details (Farrelly et al. Reference Farrelly, Lazarus and Roberts2007). Studies should also consider the role of competition for potential partners and when we predict the greatest prosocial behavior toward attractive people will occur (Raihani & Smith Reference Raihani and Smith2015; Roberts Reference Roberts2015).