The relation between testosterone levels and aggressive behavior is well established. From an evolutionary viewpoint, testosterone can explain at least part of the sex differences found in aggressive behavior. This explanation, however, is mediated by factors such as prenatal testosterone levels and basal levels of cortisol. Especially regarding sex differences in aggression during adolescence, these mediators have great influence. Based on developmental brain structure research we argue that sex differences in aggression have a pre-pubertal origin and are maintained during adolescence. Evidence of prenatal, adolescent, and adult levels of testosterone in relation to aggression taken together, support Archer's argument for sexual selection as the driver of sex differences in aggression.

This commentary argues that Evans & Levinson (E&L) should expand their two-track model to a three-track model in which biological and cultural evolution interact with the evolution of an individual's language repertories in ontogeny. It also comments on the relevance of the argument from the poverty of the stimulus and offers a caveat, based on analogous issues in biology, on the metaphor of language as a container, whether of meanings or of other content.

Inducing religious thoughts increases prosocial behavior among strangers in anonymous contexts. These effects can be explained both by behavioral priming processes as well as by reputational mechanisms. We examine whether belief in moralizing supernatural agents supplies a case for what McKay & Dennett (M&D) call evolved misbelief, concluding that they might be more persuasively seen as an example of culturally evolved misbelief.

Carruthers argues that there is no developmental or clinical evidence that metacognition is dissociable from mindreading, and hence there is no reason to think that metacognition is prior to mindreading. A closer look at the evidence, however, reveals that these conclusions are premature at best.

Sexual behaviour and mate choice are key intervening variables between attachment and life histories. We propose a set of predictions relating attachment, reproductive strategies, and mate choice criteria.

The engineer's look at how the mind works omits a central piece of the puzzle. It ignores the dynamic of motivations and the social context in which mindreading and metacognition evolved and developed in the first place. Mindreading and metacognition derive from a primacy of affective mindreading and meta-affectivity (e.g., secondary emotions such as shame or pride), both co-emerging in early development.

As Archer argues, recent developmental data on human physical aggression support the sexual selection hypothesis. However, sex differences are largely due to males on a chronic trajectory of aggression. Maternal characteristics of these males suggest that, in societies with low levels of physical violence, females with a history of behavior problems largely contribute to maintenance of physical aggression sex differences.

Del Giudice proposes that short-term mating strategies are adaptive for attachment-avoidant men. We argue that this model (1) does not apply to the majority of avoidant men (fearful-avoidants); (2) is based on limited evidence that the remaining subset of avoidant men (dismissing-avoidants) engage in short-term mating strategies; and (3) disregards the importance of pair bonding even for dismissing-avoidants.

Evans & Levinson (E&L) argue that language universals are a myth. Christiansen and Chater (2008) have recently suggested that innate universal grammar is also a myth. This commentary explores the connection between these two theses, and draws wider implications for the cognitive science of language.

McKay & Dennett (M&D) identify positive illusions as fulfilling the criteria for an adaptive misbelief, but could there be other types of beliefs that may qualify as adaptive misbeliefs? My commentary addresses this and other questions through identifying belief in free will as a potential candidate as an adaptive misbelief.

McKay & Dennett (M&D) convincingly argue against many proposals for adaptively functioning misbelief, but the conclusion that true beliefs are generally adaptive does not follow. Adaptive misbeliefs may be few in kind but many in number; maladaptive misbeliefs may routinely elude selective pruning; reproductively neutral misbeliefs may abound; and adaptively grounded beliefs may reliably covary with but not truthfully represent reality.

Mindreading in schizophrenia has been shown to be impaired in a multitude of studies. Furthermore, there is increasing evidence to suggest that metacognition is damaged as well. Lack of insight, or the inability to recognise one's own disorder, is an example of such a failure. We suggest that mindreading and metacognition are linked, but separable.

In the first part of this response, commentators' critiques to the target article are reviewed and addressed. The main discussion topics are the role of attachment in developmental plasticity; the relationship between attachment, mating, and reproductive strategies; the existence, magnitude, and developmental timing of sex differences in attachment; the adaptiveness of insecure styles; and the neurobiology of attachment and reproduction. The model's assumptions are clarified, and a number of methodological issues that can confound the interpretation of research findings are examined. In the second part, various proposals made by commentators are synthesized, and directions for future research and theoretical improvement are outlined. In addition, the issue of disorganized and fearful attachment is tentatively addressed. It is argued that different theoretical perspectives are converging toward a consistent and comprehensive theory of human reproductive strategies.

Evans & Levinson (E&L) perform a major service for cognitive science. The assumption of Chomskyan generative linguistics – that there are absolute unrestricted universals of grammatical structure – is empirically untenable. However, E&L are too reluctant to abandon word classes and grammatical relations in syntax. Also, a cognitive scientist can already draw on a substantial linguistics literature on variationist, evolutionary models of language.

Nothing is gained by opposing “sexual selection” and “social roles,” or by proclaiming the supremacy of one over the other. Instead, we should develop a unitary model of gene-culture coevolution, allowing for the complex interaction of both, and varying importance of each, all within our double, species-specific, adaptive, evolutionary track.

This commentary focuses on evidence from autism concerning the relation between metacognition and mindreading. We support Carruthers' rejection of models 1 (independent systems) and 3 (metacognition before mindreading), and provide evidence to strengthen his critique. However, we also present evidence from autism that we believe supports model 2 (one mechanism, two modes of access) over model 4 (mindreading is prior).

According to Aristotle, humans are the rational animal. The borderline between rationality and irrationality is fundamental to many aspects of human life including the law, mental health, and language interpretation. But what is it to be rational? One answer, deeply embedded in the Western intellectual tradition since ancient Greece, is that rationality concerns reasoning according to the rules of logic – the formal theory that specifies the inferential connections that hold with certainty between propositions. Piaget viewed logical reasoning as defining the end-point of cognitive development; and contemporary psychology of reasoning has focussed on comparing human reasoning against logical standards.

Bayesian Rationality argues that rationality is defined instead by the ability to reason about uncertainty. Although people are typically poor at numerical reasoning about probability, human thought is sensitive to subtle patterns of qualitative Bayesian, probabilistic reasoning. In Chapters 1–4 of Bayesian Rationality (Oaksford & Chater 2007), the case is made that cognition in general, and human everyday reasoning in particular, is best viewed as solving probabilistic, rather than logical, inference problems. In Chapters 5–7 the psychology of “deductive” reasoning is tackled head-on: It is argued that purportedly “logical” reasoning problems, revealing apparently irrational behaviour, are better understood from a probabilistic point of view. Data from conditional reasoning, Wason's selection task, and syllogistic inference are captured by recasting these problems probabilistically. The probabilistic approach makes a variety of novel predictions which have been experimentally confirmed. The book considers the implications of this work, and the wider “probabilistic turn” in cognitive science and artificial intelligence, for understanding human rationality.

Evans & Levinson's (E&L's) critique of Universal Grammar fails because their methodology is flawed, as illustrated in their discussion of the Subjacency Condition. The lack of explicit analysis leads the authors to a false conclusion that is refuted by work published in this journal twenty years ago. They miss the point that unanalyzed data cannot disprove grammatical hypotheses.

My response is organized into three sections. The first revisits the theme of the target article, the explanatory power of sexual selection versus social role theory. The second considers the range and scope of sexual selection, and its application to human sex differences. Two topics are examined in more detail: (1) the paternity uncertainty theory of partner violence; (2) evolution of inter-group aggression. Section 4 covers ultimate and proximal explanations and their integration within an ethological approach. I consider the development of sex differences in aggression, and their causal mechanisms, within this framework.

Most human beliefs are acquired through communication, and so are most misbeliefs. Just like the misbeliefs discussed by McKay & Dennett (M&D), culturally transmitted misbeliefs tend to result from limitations rather than malfunctions of the mechanisms that produce them, and few if any can be argued to be adaptations. However, the mechanisms involved, the contents, and the hypothetical adaptive value tend to be specific to the cultural case.