Fincher & Thornhill (F&T) present a powerful case for the relationship between parasite-stress and religiosity. We argue, however, that the United States may be more religious than can be accounted for by parasite-stress. This greater religiosity might be attributable to greater sensitivity to immigration, which may hyperactivate evolved mechanisms that motivate avoidance of potential carriers of novel parasites.

We agree with Frost that the variety of orthographies in the world's languages complicates the task of “cracking the orthographic code.” Frost suggests that orthographic processing must therefore differ between orthographies. We suggest that the same basic orthographic processes are applied to all languages. Where languages differ is in what the reader must do with the results of orthographic processing.

Dixon et al. suggest that the psychological literature on intergroup relations should shift from theorizing “prejudice reduction” to “social change.” A focus on social change exposes the importance of psychological theories involving collective phenomena like social norms and institutions. Individuals' attitudes and emotions may follow, rather than cause, changes in social norms and institutional arrangements.

Guala raises important questions about the misinterpretation of experimental studies that have found that subjects engage in costly punishment. Instead of positing that punishment is the solution for social dilemmas, earlier research posited that when individuals facing a social dilemma agreed on their own rules and used graduated sanctions, they were more likely to have robust solutions over time.

We find problems with Vaesen's treatment of the primatological research, in particular his analysis of foresight, function representation, and social intelligence. We argue that his criticism of research on foresight in great apes is misguided. His claim that primates do not attach functions to particular objects is also problematic. Finally, his analysis of theory of mind neglects many distinctions.

I reject Lindquist et al.'s implicit claim that all emotion theories other than constructionist ones subscribe to a “brain locationist” approach. The neural mechanisms underlying relevance detection, reward, attention, conceptualization, or language use are consistent with many theories of emotion, in particular componential appraisal theories. I also question the authors' claim that the meta-analysis they report provides support for the specific assumptions of constructionist theories.

Contrary to Vaesen's argument that humans are unique with respect to nine cognitive capacities essential for tool use, we suggest that although such cognitive processes contribute to variation in tool use, it does not follow that these capacities are necessary for tool use, nor that tool use shaped cognition per se, given the available data in cognitive neuroscience and behavioral biology.

A view of inequality as a relationship between the advantaged and the disadvantaged has gained considerable currency in psychological research. However, the implications of this view for theories and interventions designed to reduce inequality remain largely unexplored. Drawing on the literature on close relationships, we identify several key features that a relational theory of social change should include.

Claims regarding negative strong reciprocity do indeed rest on experiments lacking established external validity, often without even a small “menu of options.” Guala's review should prompt strong reciprocity proponents to extend the real-world validity of their work, exploring the preferences participants bring to experiments. That said, Guala's approach fails to differentiate among group selection approaches and glosses over cross-cultural variability.

Analysis of individual differences in religious observance in a Belizean community showed that the most religious (pastors and church workers) reported more illnesses, and that there was no tendency for the religiously observant to restrict their interactions to family or extended family. Instead, the most religiously observant tended to have community roles that widened their social contact: religion did not aid isolation – thus violating a key assumption of the parasite-stress theory of sociality.

Reading speed matters in most real-world contexts, and it is a robust and easy aspect of reading to measure. Theories of reading should account for speed.

Because of the complexity of human emotional responses, invariants must be sought not in the responses themselves, but in their generating mechanisms. Lindquist et al. show that functional locationism is a theoretical dead end; their proposed mechanistic framework is a first step toward better models of emotional behavior. We caution, however, that emotions may still be quasi-natural perceptual types.

We qualify Frost's proposals regarding letter-position coding in visual word recognition and the universal model of reading. First, we show that perceptual uncertainty regarding letter position is not tied to European languages – instead it is a general property of the cognitive system. Second, we argue that a universal model of reading should incorporate a developmental view of the reading process.

Different groups, because they are perceived to pose different threats, elicit different prejudices. Collective action by disadvantaged groups can amplify the perception of specific threats, with predictable and potentially counterproductive consequences. It is important to carefully consider the threat-based psychology of prejudice(s) before implementing any strategy intended to promote positive social change.

We are in vehement agreement with most of Vaesen's key claims. But Vaesen fails to consider or rebut the possibility that there are deep causal dependencies among the various cognitive traits he identifies as uniquely human. We argue that “higher-order relational reasoning” is one such linchpin trait in the evolution of human tool use, social intelligence, language, and culture.

In the target article, we presented the hypothesis that parasite-stress variation was a causal factor in the variation of in-group assortative sociality, cross-nationally and across the United States, which we indexed with variables that measured different aspects of the strength of family ties and religiosity. We presented evidence supportive of our hypothesis in the form of analyses that controlled for variation in freedom, wealth resources, and wealth inequality across nations and the states of the USA. Here, we respond to criticisms from commentators and attempt to clarify and expand the parasite-stress theory of sociality used to fuel our research presented in the target article.

Guala does not go far enough in his critique of the assumption that human decisions about sharing made in the context of experimental game conditions accurately reflect decision-making under real conditions. Sharing of hunted animals is constrained by cultural rules and is not “spontaneous cooperation” as assumed in models of weak and strong reciprocity. Missing in these models is the cultural basis of sharing that makes it a group property rather than an individual one.

Lindquist et al. remark that not all fear instances lead to heightened amygdalar activity and, instead, point to roles of the amygdala in detecting “motivationally salient “or “emotionally impactful” stimuli. By reviewing research on the amygdala's functions in episodic-autobiographical memory, we further emphasize the involvement of the amygdala in coding the subjective relevance and extracting the biological and social significance of the stimuli.

Vaesen infers unique properties of mind from the appearance of specific cultural innovation – a correlation without causal direction. Shifts in habitat, population density, and group dynamics are the only independently verifiable incentives for changes in cultural practices. The transition from Acheulean to Late Stone Age technologies requires that we consider how population and social dynamics affect cultural innovation and mental function.

Languages may get the writing system they deserve or merely a writing system they can live with – adaption without optimization. A universal theory of reading reflects the general dependence of writing on language and the adaptations required by the demands of specific languages and their written forms. The theory also can be informed by research that addresses a specific language and orthography, gaining universality through demonstrating adaptations to language and writing input.