Individuals differ in their support for social change. We argue that examinations of inequality and change would benefit from consideration of underlying personality processes. New data suggest that Right-Wing Authoritarianism and Social Dominance Orientation, indicators of support for inequality, may be motivated by biologically driven personality processes, particularly those related to positive-approach motivation.

In a unified theory of human reciprocity, the strong and weak forms are similar because neither is biologically altruistic and both require normative motivation to support cooperation. However, strong reciprocity is necessary to support cooperation in public goods games. It involves inflicting costs on defectors; and though the costs for punishers are recouped, recouping costs requires complex institutions that would not have emerged if weak reciprocity had been enough.

This commentary (1) raises the question about the possible conflation of core affect with the neural representation of interoceptive changes in regard to whether biological value is subpersonal or must be experienced, and (2) proposes that Wundt's third dimension of core affect – strain-relaxation – can be accounted for in the target model under a generalised predictive model of attention.

Evolutionary questions require specialized approaches, part of which are comparisons between close relatives. However, to understand the origins of human tool behavior, comparisons with solely chimpanzees are insufficient, lacking the power to identify derived traits. Moreover, tool use is unlikely a unitary phenomenon. Large-scale comparative analyses provide an alternative and suggest that tool use co-evolves with a suite of cognitive traits.

Guala notes that low-cost punishment is the main mechanism that deters free-riding in small human communities. This mechanism is complemented by unusual human vulnerability to gossip. Defenders of an evolutionary discontinuity supporting human sociality might seize on this as an alternative to enjoyment of moralistic aggression as a special adaptation. However, the more basic adaptation of language likely suffices.

Parental brain responses to baby stimuli constitute a unique model to study brain-basis frameworks of emotion. Results for baby-cry and picture stimuli may fit with both locationist and psychological constructionist hypotheses. Furthermore, the utility of either model may depend on postpartum timing and relationship. Endocrine effects may also be critical for accurate models to assess mental health risk and treatment.

We agree with many of the principles proposed by Frost but highlight crucial caveats and report research findings that challenge several assertions made in the target article. We discuss the roles that visual processing, development, and bilingualism play in visual word recognition and reading. These are overlooked in all current models, but are fundamental to any universal model of reading.

A theoretical framework is required that explains why and how cross-group contact reduces collective action and how the demobilizing effects can be counteracted. We propose that at least two mechanisms are involved: an affective process whereby the positive affect created offsets negative emotions and action tendencies, and a more strategic process whereby individual advancement comes to seem like a possibility.

Vaesen argues that functional knowledge differentiates humans from non-human primates. However, the rationale he provides for this position is open to question – with respect to both the underlying theoretical assumptions and inferences drawn from certain empirical studies. Indeed, there is some recent empirical work that suggests that functional fixedness is not necessarily uniquely human. I also question the central role of stable function representations in Vaesen's account of tool production and use.

Guala is right to draw attention to the difficulty of extrapolating from the experimental evidence for weak or strong reciprocity to what is observed in the “wild.” However, there may be more strong reciprocity in real-world communities than he allows for, as strikingly illustrated in the example of the Mafia.

We disagree with Dixon et al. by maintaining that prejudice is primarily rooted in aversive reactions toward out-group members. However, these reactions are not indicative of negative attributes, such as trait bigotry, but rather normative homophily for peers with similar perceived attributes. Cognitive biases such as stereotype threat perpetuate perceptions of inequipotential and subsequent discrimination, irrespective of individuals' personality characteristics.

The search for a universal theory of reading is misguided. Instead, theories should articulate general principles of neural computation that interact with language-specific learning environments to explain the full diversity of observed reading-related phenomena across the world's languages.

Emotional reactions are rather flexible, due to the schema-like organization of complex socio-emotional situations. Some data on emotion development, and on certain pathological conditions such as alexithymia, give further support for the psychological constructivist view put forward by Lindquist et al. Narrative organization is a key component of this schematic organization. The self-related nature of narrative organization provides scaffolding to the contextual dependency of emotions.

We applaud Ram Frost for highlighting the need for multicultural perspectives while developing universal models of visual word recognition. We second Frost's proposal that factors like lexical morphology should be incorporated besides purely orthographic features in modeling word recognition. In support, we provide fresh evidence from Hindi (written in Devanagari), an example of hitherto under-represented alphasyllabic orthographies, in which flexible encoding of akṣara (character) position is constrained by the morphological structure of words.

Strong reciprocity is not the only account that can explain costly punishment in the lab; it can also be explained by reputation-based accounts. We discuss these two accounts and suggest what kinds of evidence would support the two different alternatives. We conclude that the current evidence favors a reputation-based account of costly punishment.

In their analyses of the neural correlates of discrete emotionality, Lindquist et al. do not consider the numerous drawbacks to inferring psychological processes based on currently available cognitive neurometric technology. The authors also disproportionately emphasize the relevance of neuronal activation over deactivation, which, in our opinion, limits the scope and utility of their conclusions.

The focus on negative attitudes toward other groups has led to a dichotomy between the prejudice reduction and the collective action approach. To solve the resulting problems identified by Dixon et al., we suggest analyzing the psychological processes underlying the construction of relationships (and their alternatives) between own and other groups.

Comparing cognitive functions between humans and nonhuman primates is helpful for understanding human tool use. We comment on the latest insights from comparative research on executive control functions. Based on our own work, we discuss how even a mental function in which non-human primates outperform humans might have played a key role in the development of tool use.