If our knowledge of human cognition were based solely on research with participants younger than the age of 2 years, there would be no basis for the relational reinterpretation hypothesis, and Darwin's continuity theory would be safe as houses. Because many of the shortcomings cited apply to human infants, we propose how a consideration of cognitive development would inform the relational reinterpretation hypothesis.

Studies of the role of imprinted genes in psychological phenomena are long overdue. The target article is comprehensive, presenting a wealth of important and convergent evidence, and provides an excellent point of departure for further research. However, the authors' evidentiary grasp exceeds the explicatory capacity of the proposed model. Greater genotypic and phenotypic precision would significantly enhance its predictive power.

Rips et al.'s arguments for rejecting basic number representations as a precursor of the natural number system are exclusively based on analog number coding. We argue that these arguments do not apply to place coding, a type of basic number representation that is not considered by Rips et al.

Leech et al.'s demonstration that analogical reasoning can be an emergent property of low-level incremental learning processes is critical for analogical theory. Along with insights into neural learning based on the salience of dynamic spatio-temporal structure, and the neural priming mechanism of repetition suppression, it establishes relational primacy as a plausible theoretical description of how brains make analogies.

The empirical support for the shared circuits model (SCM) is mixed. We review recent results from our own lab and others supporting a central claim of SCM that mirroring occurs at multiple levels of representation. By contrast, the model is silent as to why human infants are capable of showing imitative behaviours mediated by a mirror system. This limitation is a problem with formal models that address neither the neural correlates nor the behavioural evidence directly.

Selection through iterated learning explains no more than other non-functional accounts, such as Universal Grammar (UG), why language is so well designed for communicative efficiency. It does not predict several distinctive features of language, such as central embedding, large lexicons, or the lack of iconicity, which seem to serve communication purposes at the expense of learnability.

We dispute Penn et al.'s claim of the sharp functional discontinuity between humans and nonhumans with evidence in bottlenose dolphins (Tursiops truncatus) of higher-order generalizations: spontaneous integration of previously learned rules and concepts in response to novel stimuli. We propose that species-general explanations that are “bottom-up” in approach are more plausible than Penn et al.'s innatist approach of a genetically prespecified supermodule.

Language is shaped by its environment, which includes not only the brain, but also the public context in which speech acts are effected. To fully account for why language has the shape it has, we need to examine the constraints imposed by language use as a sequentially organized joint activity, and as the very conduit for linguistic diffusion and change.

The reliable covariation between numerosity and spatial extent is considered as a strong constraint for inferring the successor principle in numerical cognition. We suggest that children can derive a general number concept from the (experientially) infinite succession of spatial positions during object manipulation.

Imprinted genes are predicted to affect interactions among relatives. Therefore, variant alleles at imprinted loci are promising candidates for playing a causal role in disorders of social behavior. The effects of imprinted genes evolved in the context of patterns of asymmetric relatedness that existed within social groups of our ancestors.

The authors propose that analogical reasoning may be achieved without conscious or explicit deliberation. The argument would be strengthened by more convincingly demonstrating instances of analogy that do not require explicit deliberation. Recent findings demonstrate that deliberative or explicit strategies are not necessary for flexible expression under novel circumstances (Greene et al. 2001) to include analogical transfer (Gross & Greene 2007). This issue is particularly critical because the existence of relational priming poses a serious challenge to the widely held notion that flexible expression of learned relations requires deliberative processes.

I suggest that layer 4 of the shared circuits model (SCM) should monitor the failure of performing an action, instead of output inhibition, to obtain actual/possible and self/other distinctions. The target article's assumption of selective inhibition leaves some questions unanswered, such as the criteria for the selection. Monitoring failure can answer these questions because failure does not require selection. It also provides a basis for more likely explanation for the phylogenetic and ontogenetic origin of both monitoring and output inhibition.

Through the second year, children's copying behaviour shifts from a focus on emulating to a focus on imitating. This shift can be explained by a change in focus from copying others to satisfy cognitive motivations to copying in order to satisfy social motivations. As elegant and detailed as the shared circuits model (SCM) is, it misses this crucial, motivation-based feature of imitation.

Humans, including preschool children, exhibit role-based relational reasoning, of which analogical reasoning is a canonical example. The “role-less” connectionist model proposed in the target article is only capable of conditional paired-associate learning.

Studies by Gardiner and colleagues connecting musical pitch and arithmetic learning support Rips et al.'s proposal that natural number concepts are constructed on a base of innate abilities. Our evidence suggests that innate ability concerning sequence (“Basic Sequencing Capability” or BSC) is fundamental. Mathematical engagement relating number to BSC does not develop automatically, but, rather, should be encouraged through teaching.

Meaning construction through language requires advanced mental operations also necessary for other higher-order, specifically human behaviors. Biological evolution slowly improved conceptual mapping capacities until human beings reached the level of double-scope blending, perhaps 50 to 80 thousand years ago, at which point language, along with other higher-order human behaviors, became possible. Languages are optimized to be driven by the principles and powers of double-scope blending.

Combined with recent evolutionary psychological theories, Crespi & Badcock's (C&B's) intragenomic conflict theory of the social brain suggests that schizophrenics are more religious, and autistics are less religious, than the normal population. Combined with the generalized Trivers-Willard hypothesis (gTWH), it suggests that schizophrenics have more daughters, and autistics have more sons, than expected.

The target article provides a convincing argument that nonhuman animals cannot process role-governed rules, relational schemas, and so on, in a human-like fashion. However, actual human performance is often more similar to that of nonhuman animals than Penn et al. admit. The kind of rule-governed performance the authors take for granted may rely to a substantial degree on language on external symbol systems such as those provided by language and culture.

Historical language change (“glossogeny”), like evolution itself, is a fact; and its implications for the biological evolution of the human capacity for language acquisition (“phylogeny”) have been ably explored by many contemporary theorists. However, Christiansen & Chater's (C&C's) revolutionary call for a replacement of phylogenetic models with glossogenetic cultural models is based on an inadequate understanding of either. The solution to their “logical problem of language evolution” lies before their eyes, but they mistakenly reject it due to a supposed “circularity trap.” Gene/;culture co-evolution poses a series of difficult theoretical and empirical problems that will be resolved by subtle thinking, adequate models, and careful cross-disciplinary research, not by oversimplified manifestos.

Relational representation abilities are a crucial cognitive difference between human and nonhuman animals. We argue that relational reasoning and representation supports the development of culture that increases in complexity. Thus, these abilities are a force that magnifies the apparent difference in cognitive abilities between humans and nonhumans.