The investigative strategy that Vaesen uses presumes that cognitive skills are to some extent hardwired; developmentally plastic traits would not provide the relevant comparative information. But recent views of cognition that stress external resources, and evolutionary accounts such as cultural niche construction, urge us to think carefully about the role of technology in shaping cognition.

Lindquist et al. assess the neural evidence for locationist versus psychological construction accounts of human emotion. A wealth of experimental and clinical investigations show that individual differences in emotion and personality influence emotion processing. These factors may also influence the brain's response to emotional stimuli. A synthesis of the relevant neuroimaging data must therefore take these factors into consideration.

The link between parasite-stress and complex psychological dispositions implies that the social, political, and economic benefits likely to flow from public health interventions that reduce rates of non-zoonotic infectious disease are far greater than have traditionally been thought. We sketch a prudential and ethical argument for increasing public health resources globally and redistributing these to focus on the alleviation of parasite-stress in human populations.

We agree with Frost that flexible letter-position coding is unlikely to be a universal property of word recognition across different orthographies. We argue that it is particularly unlikely in morphologically rich languages like Finnish. We also argue that dual-route models are not overly flexible and that they are well equipped to adapt to the linguistic environment at hand.

We suggest that the linguistic characteristics of letters also need to be considered to fully understand how a reader processes printed words. For example, studies in Korean showed that unambiguity in the assignment of letters to their appropriate onset, vowel, or coda slot is one of the main sources of the letter-transposition effect. Indeed, the cognitive system that processes Korean is tuned to the structure of the Korean writing system.

Plasticity of body representation fundamentally underpins human tool use. Recent studies have demonstrated remarkably complex plasticity of body representation in humans, showing that such plasticity (1) occurs flexibly across multiple time scales and (2) involves multiple body representations responding differently to tool use. Such findings reveal remarkable sophistication of body plasticity in humans, suggesting that Vaesen may overestimate the similarity of such mechanisms in humans and non-human primates.

The standard theories of cooperation in humans, which depend on repeated interaction and reputation effects among self-regarding agents, are inadequate. Strong reciprocity, a predisposition to participate in costly cooperation and the punishment, fosters cooperation where self-regarding behaviors fail. The effectiveness of socially coordinated punishment depends on individual motivations to participate, which are based on strong reciprocity motives. The relative infrequency of high-cost punishment is a result of the ubiquity of strong reciprocity, not its absence.

The target article by Lindquist et al. considers discrete emotions. This commentary argues that these are but a minor part of human emotional abilities, unifying us with animals. Uniquely human emotions are aesthetic emotions related to the need for the knowledge of “high” cognition, including emotions of the beautiful, cognitive dissonances, and musical emotions. This commentary touches on their cognitive functions and origins.

At least four conceptually distinct mechanisms may mediate relations between parasite-stress and cultural outcomes: genetic evolution, developmental plasticity, neurocognitive flexibility, and cultural transmission. These mechanisms may operate independently or in conjunction with one another. Rigorous research on specific mediating mechanisms is required to more completely articulate implications of parasite stress on human psychology and human culture.

We agree that promoting intergroup harmony “carries insidious, often unacknowledged, ‘system-justifying’ consequences” (sect. 4.1.3, para. 2) and identify several ways in which “benevolent” and “complementary” stereotypes, superordinate identification, intergroup contact, and prejudice reduction techniques can undermine social change motivation by reinforcing system-justifying beliefs. This may “keep the peace,” but it also prevents individuals and groups from tackling serious social problems, including inequality and oppression.

The evolution of religious traditions may be partially explained by out-group avoidance due to pathogen stress. However, many religious rituals may increase rather than decrease performers' susceptibility to infection. Moreover, religions often spread through proselytizing, which requires out-group interaction; and in other cases, the benefits of economic exchange increase religious pluralism and social interactions with out-groups.

I agree with Vaesen that it is a mistake to discard tool use as a hallmark of human cognition. I contend, nonetheless, that tools are not simply external markers of a distinctive human mental architecture. Rather, they actively and meaningfully participate in the process by which hominin brains and bodies make up their sapient minds.

We argue that standard experiments supporting the existence of “strong reciprocity” do not represent many cooperative situations outside the laboratory. More representative experiments that incorporate “earned” rather than “windfall” wealth also do not provide evidence for the impact of strong reciprocity on cooperation in contemporary real-life situations or in evolutionary history, supporting the main conclusions of the target article.

Lindquist et al. provide a convincing case against what they call the locationist account of emotion. Their quantitative approach elegantly illustrates the shortcomings of this still-entrenched viewpoint. Here, I discuss how a network perspective will advance our understanding of structure-function mappings in general, and the relationship between emotion and cognition in the brain.

Parafoveal preview benefit (PB) is an implicit measure of lexical activation in reading. PB has been demonstrated for orthographic and phonological but not for semantically related information in English. In contrast, semantic PB is obtained in German and Chinese. We propose that these language differences reveal differential resource demands and timing of phonological and semantic decoding in different orthographic systems.

Developmental perspectives on prejudice provide a fundamental and important key to the puzzle for determining how to address prejudice. Research with historically disadvantaged and advantaged groups in childhood and adolescence reveals the complexity of social cognitive and moral judgments about prejudice, discrimination, bias, and exclusion. Children are aware of status and hierarchies, and often reject the status quo. Intervention, to be effective, must happen early in development, before prejudice and stereotypes are deeply entrenched.

Although we agree that a constructivist approach to emotional experience makes sense, we propose that implicit (visceromotor and somatomotor) emotional processes are dissociable from explicit (attention and reflection) emotional processes, and that the conscious experience of emotion requires an integration of the two. Assessments of implicit emotion and emotional awareness can be helpful in the neuroscientific investigation of emotion.

The target article misunderstands the research program it criticizes. The work of Boyd, Richerson, Fehr, Gintis, Bowles and their collaborators has long included the theoretical and empirical study of models both with and without diffuse costly punishment. In triaging the situation, we aim to (1) clarify the theoretical landscape, (2) highlight key points of agreement, and (3) suggest a more productive line of debate.

Writing systems encode linguistic information in diverse ways, relying on cognitive procedures that are likely to be general purpose rather than specific to reading. Optimality in reading for meaning is achieved via the entire communicative act, involving, when the need arises, syntax, nonlinguistic context, and selective attention.

Fincher & Thornhill's (F&T's) parasite-stress theory of sociality is supported largely by correlational evidence; its persuasiveness would increase significantly via lab and natural experiments and demonstrations of its mediating role. How the theory is linked to other approaches to group differences in psychological differences and to production and dissemination of cultural ideas and practices, need further clarification. So does the theory's view on the possible reduction of negative group interactions.