Human Complex Systems

A recent article argues that pure working memory in humans and chimpanzees have the  same size.  However, the data offered to support this claim show the opposite, namely that the  size of pure working memory in chimpanzees is smaller than that of humans.  In addition, extensive data show that the effective size of working memory in chimpanzees is much smaller than in humans.  Altogether, there are quantitative differences in the size of working memory (pure or effective) between chimpanzees and humans leading to significant qualitative differences between them.

In a recent article, it is argued that the pure working memory in humans and the chimpanzees are homologous with the same parameter values for the size of pure working memory.  However, the data offered to support this claim show the opposite, namely that the pure working size of chimpanzees is smaller than that of humans.  In addition, extensive data show that the effective size of working memory in the chimpanzees is much smaller than in humans.  Altogether, there are qualitative differences between the chimpanzees and humans deriving from quantitative differences in the size of their working memory (pure or effective).

In a recent article, it is argued that the pure working memory in humans and the chimpanzees are homologous with the same parameter values for the size of pure working memory.  However, the data offered to support this claim show the opposite, namely that the pure working size of chimpanzees is smaller than that of humans.  In addition, extensive data show that the effective size of working memory in the chimpanzees is much smaller than in humans.  Altogether, there are qualitative differences between the chimpanzees and humans deriving from quantitative differences in the size of their working memory (pure or effective).

Mithen describes our book, Human Thought and Social Organization, as unintelligible. Since a previous review by Bojka Milicic showed an excellent grasp of the full range of implications of the argument and another by Radu Umbres showed a good understanding of it, we are confident that Mithen's description is wrong as a matter of fact.  In our reply we address what led him astray.

The claim that extant terminologies are optimal solutions in a space of all possible terminologies depends on invalidly assuming any partition of a set of genealogical relations is a possible kinship terminology.  Instead, kinship terminologies have a particular type of logical/formal structure that is generative with categories providing for classification that is reciprocal.  As a consequence, all terminologies, extant or hypothetical, are optimal solutions in the sense this term is used in the claim made about kinship terminologies. 

D’un point de vue conceptuel, les systèmes de parenté reposent sur des modes de représentation culturelle que nous appelons terminologies de parenté et à partir desquelles les limites, la forme et la structure des principes d’organisation sociale sont culturellement élaborés. Contrairement à ce que les anthropologues tiennent depuis longtemps pour acquis, une terminologie n’est pas forcément inhérente aux relations généalogiques, ces dernières découlant de la logique structurelle de la terminologie de parenté. La structure de la terminologie, représentée sous une forme algébrique, peut être produite à partir des principaux termes de parenté, suivant un principe supposé universel de structures terminologiques de la parenté. Les terminologies diffèrent, sur le plan culturel, selon les principales expressions et équations utilisées pour les élaborer. Cela implique un changement de paradigme qui nous ferait passer de la généalogie considérée comme fondement essentiel des relations de parenté à un modèle dans lequel la parenté intégrerait à la fois des termes de parenté propres à un système de représentations culturellement constitué auquel nous nous référons dans la terminologie de parenté, et une dimension généalogique élaborée de manière récursive en utilisant les relations parents/enfants. Ces deux domaines sont fondés sur un espace familial comprenant les positions de parents/enfants, conjoints, germains.

Comparing the effect of statistical distributions on the outcome of the “treadmill” model relating average skill level achieved through imitation to demogaphic factors is premature as the model incorporates an invalid assumption. The model incorrectly assumes that the imitation bias remains constant with increasing average skill level and is contradicted by data on hunter-gatherer and oceanic fishing groups showing that for these groups there is no relationship between the interacting population size and tool complexity.

Alex Mesoudi observes that the “treadmill” model for relating average skill level achieved through imitation to demogaphic factors implies, incorrectly, that skill levels will increase without bound.   Rather than correcting the structural problem with the model, he applies a “Band-Aid” in the form of an imitation cost to the model to force the average skill level to reach a plateau.  The model, however, incorrectly assumes that the imitation bias remains constant with increasing average skill level and, when corrected, average skill level will reach a plateau even without the added cost factor. 

 A good book review provides documentation for its evaluations, especially when they are either very positive or very negative. A good review is also faithful to what the author has written and bases criticisms or praise on accurate paraphrasing or quotes from the book. This review by Thompson fails on both accounts. Critical comments are not documented and the review is based on what Thompson imagines Read to have written, not what Read actually wrote.

A mathematical model purporting to demonstrate that the interaction population size of a group of social learners is a primary determinant of the level of technological complexity achieved by the members of that group through imitation of the most skilled individual in the group has been proposed.  Empirical validation of the model has been attempted with archaeological data from Tasmanian hunter-gatherers and ethnographic fishing data from Oceania, but these data do not support the model. Data from a wide variety of hunter-gatherer groups show, instead, that implement complexity varies with an interaction effect between risk and number of annual moves and not with the interaction population size. Data from the Polar (Inuit) Eskimo and the Angmaksalik Inuit on the east coast of Greenland show that complex implements were part of both group’s technological repertoire even though each had interaction population sizes limited to a few hundred individuals, in direct contradiction with predictions from the mathematical model. The problem with the model lies in an invalid assumption.