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Archive for March, 2013|Monthly archive page

Giuliana Pulvirenti: Review of Farine R. D. “Social network analysis of mixed-species flocks: exploring the structure and evolution of interspecific social behavior”.

In Philosophy of Biology, Pulvirenti, Review on March 29, 2013 at 1:20 PM

Functional explanations advocated for mixed-species groups (mainly foraging and anti-predator advantages) are based on top-down approaches that implicitly assume the species as fixed and static social structures and shift the analysis of fitness benefits and costs from the level of individuals to the one of the groups/species. According to Farine, this operation of over-simplification leads to cursory inferences. On the contrary, a bottom-up approach, usually used to study intraspecific sociality, could provide an insight and a better understanding of the emergent and dynamic properties at each level of the social system. In this perspective, the author proposes Social Network Analysis (SNA) as a tool to measure inter-individual interaction within mixed species flocks. His aim is to explore the different roles within the flocks and the individual variations of sociality, as well as the fitness consequences that such variations leads to both individual and community structure. SNA main strength is the possibility to graphically represent and quantify, at any scale between dyads and groups, specific aspects of social relationships, such as number, intensity, frequency of direct and indirect interactions and individual roles, centrality (i.e. “keystone” individuals). As an istance, Loussou & Newman (2004) found a “keystone” individual in a bottlenose dolphin community in Scotland that acted as a bridge between two subgroups, therefore playing a critical role in keeping the connection between them. However, SNA current applications raise some issues concerning spatial and temporal constraints (Wey et al. 2008). On one hand, pattern of associations vary on a case by case basis depending on habitat topology and distribution of resources, while on the other hand, it’s important to distinguish genuine social network structures from relationships explained solely by shared space use. Furthermore, traditional graph models are limited in addressing temporal questions regarding changes that may occur over a given time period. Future work must also go beyond simple description, beginning to link network structure to biological and evolutionary consequences, in order to answer the “why” questions in sociobiological and ethological studies (Hock & Fefferman 2011).

Bibliography

Farine Damien R., Garroway Colin J., Sheldon Ben C. (2012), Social network analysis of mixed-species flocks: exploring the structure and evolution of interspecific social behavior, in Animal Behaviour 84: 1271-1277.

Hock C. & Fefferman N. (2011), Extending the role of social networks to study social organization and interation structure of animal groups, in Ann. Zool. Fennici 48: 365-370.  http://www.bioone.org/doi/abs/10.5735/086.048.0604

Lusseau D. & Newman M. E. J. (2004), Identifying the role that animals play in their social networks, in Proceedings of the Royal Society B (suppl): Biological Sciences 271: 477- 481. http://rspb.royalsocietypublishing.org/content/271/Suppl_6/S477.short

Sih A., Hanser S. F. & McHugh K. A. (2009), Social network theory: new insights and issues for behavioral ecologists, in Behav. Ecol. Sociobiol. 63: 975-988. http://link.springer.com/article/10.1007%2Fs00265-009-0725-6?LI=true

Sueur C., Jacobs A., Amblard F., Petit O., King A. J. (2011), How can social network analysis improve the study of primate behavior?, in American Journal of Primatology 73: 703-719. http://onlinelibrary.wiley.com/doi/10.1002/ajp.20915/abstract

Wey T., Blumstein D. T., Shen W. & Jordan F. (2008), Social network analysis of animal behaviour: a promising tool for the study of sociality, in Animal Behaviour 75: 333-344. http://www.colbud.hu/apc-aa/img_upload/4d11dfd490c468ca39fcefabae592944/JordanAniBe2008.pdf

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

In d'Almeida, Game Theory on March 28, 2013 at 9:06 AM

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.

André F. d’Almeida, M.Phil

Bibliography

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.

Laura Desirée Di Paolo: Review of Heyes, C. “What’s Social About Social Learning?”

In Di Paolo, Philosophy of Cognitive Sciences, Review on March 28, 2013 at 9:00 AM

As always, Cecilia Heyes asks the right question: What’s social about social learning? Nothing, she answers, except for social inputs. There are two points: (1) social and asocial learning use same mechanisms; (2) social inputs make sociality unique. The first point is appealing, the second one looks tautological, but it is not. Let us see why. Three points: (1) the exhibited list include only three animal-learning typologies (stimulus enhancement, observational conditioning and observational learning), not considering the generally accepted distinction between emulation/imitation (e.g. Byrne & Russon, 1998) and this cannot be a slip; (2) uniqueness of social learning is trivially explained by inputs; (3) all the article looks like the pars destruens of a more completed reasoning. As a matter of fact, there is one theory, widely valued, which underlines qualitative differences among social learning strategies, saying that just one strategy produces “TRUE CULTURE” (e.g. Tomasello, 1999; 2008; 2009). Heyes’ pointing on identity of mechanisms could mean that these differences (emulation, imitation, true imitation, over-imitation) are not momentous. Therefore, we can suppose that (a) environmental factors, which in primates are social factors, affect abilities of social transmission considerably; (b) explaining sociality’ uniqueness does not require evolutionary adaptations, but simpler things as differences in inputs; (c) ontogenetic inheritance is otherwise significant. If this was the theoretical, tacit framework of this article, I could have not agreed more.

Bibliography

 

Byrne, R.W. & Russon, A.E. (1998) Learning by imitation: A hierarchical approach. Behavioural and Brain Sciences, 21: 667-721. http://web.media.mit.edu/~cynthiab/Readings/Byrne-Russon98.pdf

Heyes, C. (2011) What’s Social About Social Learning? Journal of Comparative Psychology, (online first). http://www.all-souls.ox.ac.uk/users/heyesc/Celia’s%20pdfs/94%202011%20Heyes%20What’s%20social.pdf

Tomasello, M. (1999) The Cultural Origins of Human Cognition. Harvard University Press

Tomasello, M. (2008) Origins of Human Communication. Cambridge, Ma-  London, En: MIT Press

Tomasello, M. (2009) Why We Cooperate? Cambridge, Ma-  London, En: MIT Press

Herbert Spencer and Organism-Environment Interaction

In Morganti, Philosophy of Biology on March 28, 2013 at 8:54 AM

In a recently published paper Trevor Pearce (2010) has provided an interesting account of the steps which conducted Herbert Spencer (1820-1903) to adopt the term ‘environment’ as opposed to the plural noun ‘circumstances’. According to Pearce, this shift took place as Spencer moved to a conception of both organism and environment as opposite and distinct entities. Undoubtedly, Pearce’s article has the historiographical merit of identifying some important contributions to the development of Spencer’s biological thought (such as Lamarck 1809; Chambers 1844; Comte via Martineau 1845). Nevertheless, the hypothesis that Spencer held a conception of the organism-environment interaction as that indicated by Pearce is fairly arguable. In the first place, though Spencer came to adopt the singular noun ‘environment’ (which he had found in Martineau 1845), he conceived the environment itself not as a monolithic block, but rather as a plurality of physical forces. Secondly, and most notably, he believed that those very forces were constantly redefined by organisms themselves according to their level of heterogeneity and complexity (Spencer 1864-67, I, 418, 421-23; 1870-72, I, 193-227). Thus, it is difficult to credit Spencer with a view of organism and environment as polarly opposed entities. On the whole, it is not easy to place Spencer in the history of the concept of environment. In fact, while his advocacy of the idea of a reciprocal construction of organisms and environments seems close to modern thinking, still he is quite distant from it in his constant attempt to reduce biological and ecological notions to the language of physics.

Federico Morganti

Bibliography

 

Lamarck, J.-B. (1809), Philosophie zoologique, ou exposition des considérations relatives à l’histoire naturelle des animaux (2 vols.), Dentu: Paris.

Chambers, R. (1844), Vestiges of the Natural History of Creation, J. Churchill: London.

Martineau, H. (1845), The Positive Philosophy of August Comte (2 vols.), J. Chapman: London.

Pearce, T. (2010). From ‘circumstances’ to ‘environment’: Herbert Spencer and the origins of the idea of organism-environment interaction. Studies in History and Philosophy of Biological and Biomedical Sciences 41: 241-52.

Spencer, H. (1864-67), The Principles of Biology (2 vols.), Williams and Norgate: London.

Spencer, H. (1870-72), The Principles of Psychology, 2nd ed. (2 vols.), Williams and Norgate: London.

Ivan D’Annibale: Review of Marshall, R.A.J., “Group selection and kin selection: formally equivalent approaches.”

In D'Annibale, Philosophy of Biology, Review on March 28, 2013 at 8:47 AM

The level at which natural selection “acts” has been a much debated issue in evolutionary biology (Okasha 2006), especially in connection with the evolution of altruism. Two major kinds of explanations have been proposed: group selection theory (GST) and inclusive fitness theory (IFT). Marshall (2011) surveys the most common objections to the latter, claiming that the two approaches are in fact formally equivalent. We discuss exclusively his claim of equivalence. Rewriting of the Price equation (Price 1970) yields: 1) a version of Hamilton’s rule (a basic tool in IFT); 2) a partition of selection in between-group and within-group selection (typical of GST explanations). Thus, 1) and 2) are formally equivalent. If we assume that 1) holds, then also 2) holds, and conversely. Is this the same as saying that IFT and GST are formally equivalent? The author concedes that IFT cannot be identified with Hamilton’s rule. Thus the claim of formal equivalence must be, at least as far as this article goes, re-evaluated. On the other hand, to prove formal equivalence it requires an explicit set of axioms to be given. This request seems honestly unreasonable. Even in the case where such a formal model could be described, it remains dubious that many, or any, would agree on it. The word “theory”, as in “inclusive fitness theory” and “group selection theory”, should be better understood as a set of different but related explanations (for IFT alone, in addition to Hamilton’s rule and the Price equation, population genetics and evolutionary game theory have been useful approaches, among others). In particular, formal models are currently being used with a more modest goal: to describe more limited and well defined (agreed upon) aspects of the world, in order to produce testable predictions. On a final note, even if any two of these models will be found to be formally equivalent, we may have gained a more thorough “understanding” in the process. Mathematics also, after all, is more than the axioms that we put into it.

Bibliography

Okasha, S. (2006), Evolution and the Levels of Selection, Oxford: Oxford University Press.

Marshall, J.A.R. (2011), Group selection and kin selection: formally equivalent approaches, Trends in Ecology and Evolution, 26 (7): 325-332.

Price, G.R. (1970), Selection and covariance, Nature, 227 (5257): 520-521.
(I thank all the participants in our last reading group for discussing and sharing ideas).

Natural Born Morals (Section I)

In Di Vincenzo, Moral Philosophy, Severini on March 26, 2013 at 1:04 PM

Evolutionary explanations of morality generally focus on the ability of judging in moral terms. Adaptationist accounts of morality, in particular, attempt to explain the evolution of morality in terms of the selective advantage that judging in moral terms secured for our ancestors (e.g. Ruse 1986; Joyce 2006; Street 2006). For instance, Ruse claims that “because it is biologically advantageous for us to help and co-operate, morality […] has evolved to guide and stiffen our will” (1986, p. 222). Along similar lines, Joyce claims that “the actions that morality prescribes with categorical force are those that constitute or promote, roughly speaking, cooperation” (2000, p. 714). Finally, Street claims that “certain kinds of evaluative judgments […] contributed to our ancestors’ reproductive success […] because they forged adaptive links between our ancestors’ circumstances and their responses to those circumstances, getting them to act, feel, and believe in ways that turned out to be reproductively advantageous” (2006, p. 127). The most interesting aspect is that these evolutionary explanations interpret morality as a single and distinct trait (judging in moral terms). This view implicitly assumes that there is an inborn device dedicated to moral judgments. In other terms, there is a mental module, supporting our ability of making moral judgments, which has been favoured by selection because of its efficacy in fitness-enhancing behavior. An alternative to this adaptationist account of morality, is the explanation of morality as exaptation (Prinz 2009; Fraser 2010). This point of view stresses the fact that there is no such mechanism dedicated to morality. Then morality could be an exaptation, that is the cooptation of capacities that have evolved for other purposes (Gould & Vrba, 1982). In other terms, traits that have one or no function, are employed for a new and useful one. The point is that an explanation of morality as both adaptation and exaptation is unsatisfactory. As a matter of fact, this kind of appeal to exaptation does not represent a solution, but only a shift of the problem. In this view, in fact, morality as exaptation could be conceived as a “secondary adaptation”. The question is deeper: what does a moral trait effectively consist in? The problem is that a complex ability such as the moral one, cannot be resumed under a single domain-specific trait (making moral judgments). In our view, it seem to be more consistent, both empirically and theoretically, that many abilities – evolved for different purpose(s) – could be subsumed under a socio-cultural “label” of morality that, in this sense, is conceived as part of the more general-domain of evaluative judgment. Then, the moral “domain” could be an heterogeneous domain in which cognitive, emotional, social, physiological items combine into a biological and cultural field. In this way morality encompasses at the same time some “action strategies”, such as decision making (mainly driven by utility), and general capacities of knowledge of the facts related to the external world in the form of beliefs and values (the basics for normativity).

Fabio Di Vincenzo

Eleonora Severini

Bibliography

Fraser, B. (2010), «Adaptation, exaptation, by-products and spandrels in evolutionary explanations of morality», Biological Theory, Vol. 5, No. 3, pp. 223-227.

Gould, S. J. & E. S. Vrba (1982), Exaptation – a missing term in the science of form. Paleobiology, Vol. 8, pp. 4-15.

Joyce, R. (2006), The Evolution of Morality. Cambridge MA: MIT Press.

Prinz, J. (2009), «Against moral nativism», in: Stich and His Critics (Bishop M, Murphy D, eds), pp. 167-189.

Ruse, M. and Wilson, E.O. (1986), «Moral Philosophy as Applied Science», Philosophy, Vol. 61, pp. 173-92.

Street S. (2006), «A Darwinian dilemma for realist theories of value», Philosophical Studies, Vol. 127, pp. 109-166.