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Archive for December, 2012|Monthly archive page

Morality and exaptation: adaptation is the matter.

In Moral Philosophy, Severini on December 11, 2012 at 2:33 PM

Eleonora Severini

The so-called by-product explanations of morality have been presented as an alternative to adaptationist accounts (Prinz 2009). According to Prinz, since there is no mental mechanism dedicated to the acquisition of moral norms, the fact that we make moral judgments is not an adaptation but an evolutionary accident, i.e. a by-product of capacities evolved for other purposes. According to Fraser (2010) Prinz’s stance is not inconsistent with an adaptationist account of the evolution of morality. Fraser argues that morality may be, rather than an accident, a secondary adaptation, that is an exaptation, consisting in the cooptation for a new purpose of a structure initially served other functions or none (Gould & Vrba, 1982). Thus, Fraser seems to reconcile the lack of a moral machinery with a description of morality as adaptation: that is, capacities evolved for other purpose(s) (e.g., emotional bonds with kin) have been selected for a different one (e.g., promoting cooperation between non-kin). My point is that the trouble lies inside the nature of adaptation, and it is deeper than the mere semantic question that the same trait could be defined both as adaptation or exaptation depending on which function – past or present – we are referring to. The core of exaptation is not the epistemological claim that it is difficult to tell whether a trait is an adaptation or not, but rather the “ontological objection” that most traits are not adaptations (Dupré 2002). In this sense, we cannot legitimately describe morality as adaptation (Fraser 2010). It seems more appropriate to interpret morality as a by-product only in the sense of being a contingent epiphenomenon that other adaptive mechanisms or building features make possible, not inevitable.

References

 

Dupré J. (2002), Ontology is the problem, Behavioral and Brain Sciences, 25-4, pp. 516517. 

 

Fraser B. (2010), Adaptation, exaptation, by-products and spandrels in evolutionary explanations of morality, Biological Theory, 5-3, pp. 223227.

 

Gould, S.J. & Vrba, E.S. (1982) Exaptation- A Missing Term in the Science of Form. Paleobiology, 8, 1: 4-15.

Prinz J. (2009), Against moral nativism, in Bishop M., Murphy D. (eds.), Stich and his critics, Wiley-Blackwell, pp. 167– 189.

 

 

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Networks, updates and real people. Are theoretical studies saying the right thing?

In Anthropology, d'Almeida on December 6, 2012 at 4:44 PM

André F. d’Almeida

Evolutionary Game Theory (EGT) has given several accounts on how cooperation is maintained by a population’s network structure (Ohtsuki, H., et al., 2006). These studies are based on several assumptions, namely that individuals only take into account benefits and costs and that they decide to update their strategy by comparing pay-offs with random members of the population (Roca, C.P. et al., 2009). Up until now, experimental game theory had only been able to study interactions in small networks, a world away from the thousands of nodes networks used in theoretical research. This proved difficult to accurately test theoretical models experimentally. Recently, a study where 1229 subjects play a Prisoner’s Dilemma (PD) game simultaneously (Gracia-Lázaro, C., et al., 2012) demonstrated that there are no differences in cooperation levels in homogeneous vs. heterogeneous networks. Unlike what was suggested in a Public Goods Game context (Santos, F.C. et al., 2008), where network diversity increased cooperation. Furthermore, individuals did not compare pay-offs with their neighbours but only accounted for their actions in order to make decisions, meaning that they acted reciprocally.Does this mean theoretical studies are not saying the right things? Yes and no. Yes, because theoretical studies make plenty assumptions regarding human behaviour, over-simplifying it to the level of particles with only two choices and strict rules on how individuals update strategies. No, because theoretical research only provides guidelines on the evolution of cooperation, of ultimate causation alternatives of a behaviour. It is the experimenters who must test which alternatives are proximally exhibited by real individuals, both human and non-human and provide guidelines for better theoretical models, mainly how people decide and react to social dilemmas.

 

References

Ohtsuki, H., et al. (2006) A simple rule for the evolution of cooperation on graphs and social networks. Nature, 441, 7092: 502-505. 

Roca, C.P., J.A. Cuesta, and A. Sánchez (2009) Evolutionary game theory: Temporal and spatialeffects beyond replicator dynamics. Physics of Life Reviews; 6,4: 208-249. 

Gracia-Lázaro, C., et al. (2012) Heterogeneous networks do not promote cooperation when humans play a Prisoner‚Äôs Dilemma. Proceedings of the National Academy of Sciences; 109, 32: 12922-12926. 

 Santos, F.C., M.D. Santos, and J.M. Pacheco (2008) Social diversity promotes the emergence of cooperation in public goods games. Nature; 454, 7201: 213-216.

Could plasticity provide an evolutionary understanding of variation?

In Fabris, Philosophy of Biology on December 4, 2012 at 7:00 AM

C.H.Waddington’s genetic approach still remains contemporary, after more than half of a century from its first exposition. The reason of this is mainly because it sheds light on the organism/environment regulatory mechanisms that can step up the explanation of the morphological variations that we observe everywhere in the biological realms. Waddington was the first scholar showing how the selection of biological responses to a particular environmental stimulus influence  the direction of the evolutionary change (Waddington, 1953). In the last decade,s several authors stressed the necessity to expand the epistemological boundaries of the Modern Synthesis (e.g. Pigliucci, 2007). By this point of view, the integration –as Waddington first displayed– of ontogeny and development into evolutionary explanations may result essential for understanding the biological significance of  phenotypic  novelties. Adopting such EvoDevo approach, genetics and molecular biology concur to demonstrate how “regulation” and “organism/environment feedback” play a crucial role in expressing phenotypical variation (Hiyama et al., 2012). By this line of evidences, blowing up by the Waddington’s pioneristic work, emerge how the environmental changes may have some relevant effects, not merely selective as claimed by the neo-Darwinian tradition, in promoting the evolution of the genome. Irrespectively by the extend of these effects, we must then consider the genetic and epigenetic responses exhibited by the organisms as phenotypical cues of deeper evolutionary refinements and/or switching occurring in previous canalized pathways of development. However, the comprehension of the full range of genomics plasticity is not alone suffice to provide a satisfactory evolutionary understanding of the phenomenon of morphological variation. A balance between the capacity of the genome to respond plastically to the environmental stimuli and the adaptive “opportunity” to reveal mutations, need to occur at some point of the complex organism/environment interaction. If this not the case, we have a paradox by which the mechanisms responsible for the phenomena of phenotypical variation could lead not to evolutionary adaptation, but rather to an opposite effect.       

Bibliography 

Hiyama, A., Taira, W., & Otaki, J. M. (2012). Color-pattern evolution in response to environmental stress in butterflies. Frontiers in genetics, 3, 1-6.

Pigliucci, M. (2007). Do we need an extended evolutionary synthesis? Evolution, 61, 2743-2749.

 Waddington, C. H. (1953). Genetic assimilation of an acquired character. Evolution, 7, 118-12  

Flavia Fabris