Evolution cannot explain how minds work

Cognitive performance is linked to fitness in a wild primate

Cognitive performance varies widely across animal species, but the processes underlying cognitive evolution remain poorly known. For cognitive abilities to evolve, performance must be linked to individual fitness benefits, but these links have been rarely studied in primates even though they exceed most other mammals in these traits. We subjected 198 wild gray mouse lemurs to four cognitive and two personality tests and subsequently monitored their survival in a mark-recapture study. Our study revealed that survival was predicted by individual variation in cognitive performance as well as body mass and exploration. Because cognitive performance covaried negatively with exploration, individuals gathering more accurate information enjoyed better cognitive performance and lived longer, but so did heavier and more explorative individuals. These effects may reflect a speed-accuracy trade-off, with alternative strategies yielding similar overall fitness. The observed intraspecific variation in selective benefits of cognitive performance, if heritable, can provide the basis for the evolution of cognitive abilities in members of our lineage.

Language and learning: the cognitive revolution at 60-odd

Around the middle of the last century, the prevailing psychological paradigm of behaviourism was challenged by what is now known as the cognitive revolution. Behaviourists viewed learning as changes in patterns of behaviour through reinforcement. By contrast, advocates of the cognitive approach argued that such behavioural changes were outward manifestations of computational operations on mental representations. Here we consider the current state of the cognitive revolution, focusing on the two most contentious issues in the debate: language and learning. The cognitive approach has proved to be extremely fruitful in both fields. Although contemporary learning theory has almost completely embraced the cognitive approach, the study of language has witnessed a clear empiricist trend to revert back to a kind of neo-behaviourism. Many contemporary authors contend that language is a means of communication that is learned solely through the observation of external events, and culturally transmitted to successive generations. Here, we argue that learning and language can only be properly understood from a cognitive perspective, where the mind is conceived of as a biologically underpinned computational system. As is the case in learning theory, there is abundant evidence showing that language is subserved by an autonomous cognitive system in the mind. We conclude that the cognitive revolution has fundamentally changed our understanding of the mind.

Renewed Perspectives on the Deep Roots and Broad Distribution of Animal Consciousness

The vast majority of neurobiologists have long abandoned the Cartesian view of non-human animals as unconscious automatons-acknowledging instead the high likelihood that mammals and birds have mental experiences akin to subjective consciousness. Several lines of evidence are now extending those limits to all vertebrates and even some invertebrates, though graded in degrees as argued originally by Darwin, correlated with the complexity of the animal's brain. A principal argument for this view is that the function of consciousness is to promote the survival of an animal-especially one actively moving about-in the face of dynamic changes and real-time contingencies. Cognitive ecologists point to the unique features of each animal's environment and the specific behavioral capabilities that different environments invoke, thereby suggesting that consciousness must take on a great variety of forms, many of which differ substantially from human subjective experience.

The performance of cleaner wrasse, Labroides dimidiatus, in a reversal learning task varies across experimental paradigms

Testing performance in controlled laboratory experiments is a powerful tool for understanding the extent and evolution of cognitive abilities in non-human animals. However, cognitive testing is prone to a number of potential biases, which, if unnoticed or unaccounted for, may affect the conclusions drawn. We examined whether slight modifications to the experimental procedure and apparatus used in a spatial task and reversal learning task affected performance outcomes in the bluestreak cleaner wrasse, Labroides dimidiatus (hereafter “cleaners”). Using two-alternative forced-choice tests, fish had to learn to associate a food reward with a side (left or right) in their holding aquarium. Individuals were tested in one of four experimental treatments that differed slightly in procedure and/or physical set-up. Cleaners from all four treatment groups were equally able to solve the initial spatial task. However, groups differed in their ability to solve the reversal learning task: no individuals solved the reversal task when tested in small tanks with a transparent partition separating the two options, whereas over 50% of individuals solved the task when performed in a larger tank, or with an opaque partition. These results clearly show that seemingly insignificant details to the experimental set-up matter when testing performance in a spatial task and might significantly influence the outcome of experiments. These results echo previous calls for researchers to exercise caution when designing methodologies for cognition tasks to avoid misinterpretations.

The Occurrence of Postconflict Skills in Captive Immature Chimpanzees (Pan troglodytes)

Conflict management strategies can reduce costs of aggressive competition in group-living animals. Postconflict behaviors such as reconciliation and third-party postconflict affiliation are widely accepted as social skills in primates and have been demonstrated in many species. Although immature primates possess a repertoire of species-specific behaviors, it is thought that they gradually develop appropriate social skills throughout prolonged juvenility to establish and maintain complex social relationships within their group. We examined the occurrence of postconflict skills in five immature chimpanzees (Pan troglodytes) over 15 mo, focusing on interactions that were not with the subject’s mother. We observed reconciliation, with conciliatory tendencies comparable to adults, and provide the first evidence that captive immature chimpanzees commonly reconciled using social play. However, immatures were not more likely to reconcile valuable than nonvaluable relationships. We also observed third party postconflict affiliation although at a lower level than reported for adults. Our results provide evidence for postconflict skills in immature chimpanzees but the lack of higher conciliatory tendency with valuable partners and low occurrence of third-party affiliation indicates extended juvenility may be required refine these skills. Further work is needed to investigate whether these behaviors have the same function and effectiveness as those found in adults.

A genome-wide search for epigenetically [corrected] regulated genes in zebra finch using MethylCap-seq and RNA-seq

Learning and memory formation are known to require dynamic CpG (de)methylation and gene expression changes. Here, we aimed at establishing a genome-wide DNA methylation map of the zebra finch genome, a model organism in neuroscience, as well as identifying putatively epigenetically regulated genes. RNA- and MethylCap-seq experiments were performed on two zebra finch cell lines in presence or absence of 5-aza-2′-deoxycytidine induced demethylation. First, the MethylCap-seq methodology was validated in zebra finch by comparison with RRBS-generated data. To assess the influence of (variable) methylation on gene expression, RNA-seq experiments were performed as well. Comparison of RNA-seq and MethylCap-seq results showed that at least 357 of the 3,457 AZA-upregulated genes are putatively regulated by methylation in the promoter region, for which a pathway analysis showed remarkable enrichment for neurological networks. A subset of genes was validated using Exon Arrays, quantitative RT-PCR and CpG pyrosequencing on bisulfite-treated samples. To our knowledge, this study provides the first genome-wide DNA methylation map of the zebra finch genome as well as a comprehensive set of genes of which transcription is under putative methylation control.