We argue that maximising utility does not promote survival. Hence, there is no reason to expect people to modulate effort according to a task's opportunity costs. There is also no reason why our evaluation of the marginal opportunity costs of tasks should predictably rise with repetition. Thus, the opportunity cost model cannot explain why tasks typically become harder over time.

We propose a way in which Pothos & Busemeyer (P&B) could strengthen their position. Taking a dynamic stance, we consider cognitive tests as functions that transfer a given input state into the state after testing. Under very general conditions, it can be shown that testable properties in cognition form an orthomodular lattice. Gleason's theorem then yields the conceptual necessity of quantum probabilities (QP).

A homeostatic energy model of awareness proposes that the anterior insular cortex engenders feelings that provide an amodal valuation of homeostatic energy utilization in an opponent, bivalent emotional control system. Feelings are the “common currency” which enable optimal utilization in the physical and mental behavior of a highly social primate. This model offers a different perspective.

Baumard et al.'s definition of morality is narrow and their review of empirical work on human cooperation is limited, focusing only on economic games, almost always involving strangers. We suggest that theorizing about mutualisms will benefit from considering extant empirical behavioral research far more broadly and especially from taking relational context into account.

Applying the framework proposed by Jeffery et al. to nonhuman primates moving in multilayer arboreal and terrestrial environments, we see that these animals must generate a mosaic of many bicoded spaces in order to move efficiently and safely through their habitat. Terrestrial light detection and ranging (LiDAR) technology and three-dimensional modelling of canopy movement may permit testing of Jeffery et al.'s framework in natural environments.

We question the idea that the mirror neuron system is the substrate of social affordances perception, and we suggest that most of the activity seen in the parietal and premotor cortex of the human brain is independent of mirroring activity as characterized in macaques, but rather reflects a process of one's own action specification in response to social signals.

Pothos & Busemeyer's (P&B's) query about whether quantum probability can provide a foundation for the cognitive modeling embodies so many underlying implications that the subject is far from exhausted. In this brief commentary, however, I suggest that the conceptual thresholds of the meaningful learning give rise to a typical Boltzmann's weighting measure, which indicates a statistical verisimilitude of quantum behavior in the human cognitive ensemble.

We welcome the development of a new model on effort and performance and the critique on existing resource-based models. However, considering the vast evidence for the significant impact of experienced task demand on resource allocation, we conclude that Kurzban et al.'s opportunity cost model is only valid for one performance condition: if task demand is unknown or unspecified.

As there is “dark matter” in the neuroscience of individuals engaged in dynamic interactions, similar dark matter is present in the domain of interaction between humans and cognitive robots. Progress in second-person neuroscience will contribute to the development of robotic cognitive systems, and such developed robotic systems will be used to test the validity of the underlying theories.

The evolutionary hypothesis advanced by Baumard et al. makes precise predictions on which emotions should play the main role in our moral lives: morality should be more closely linked to “avoidance” emotions (like contempt and disgust) than to “punitive” emotions (like anger). Here, we argue that these predictions run contrary to most psychological evidence.

Jeffery et al. characterize the egocentric/allocentric distinction as discrete. But paradoxically, much of the neural and behavioral evidence they adduce undermines a discrete distinction. More strikingly, their positive proposal – the bicoded map hypothesis – reflects a more complex interplay between egocentric and allocentric coding than they acknowledge. Properly interpreted, their proposal about three-dimensional spatial representation contributes to recent work on embodied cognition.

The target article by Baumard et al. uses their previous model of bargaining with outside options to explain fairness and other features of human sociality. This theory implies that fairness judgments are determined by supply and demand but humans often perceive prices (divisions of surplus) in competitive markets to be unfair.

Typically, human decision making is emotionally “hot” and does not conform to “cold” classical probability (CP) theory. As quantum probability (QP) theory emphasises order, context, superimposition states, and nonlinear dynamic effects, one of its major strengths may be its power to unify formal modeling and realistic psychological theory (e.g., information uncertainty, anxiety, and indecision, as seen in the Prisoner's Dilemma).

I contend that Kurzban et al.'s model is silent on three issues. First, the extent to which opportunity-cost computations are automatic or deliberative is unclear. Second, the role of individual differences in biasing opportunity-cost computations needs elucidating. Third, in the absence of “next-best” tasks, task persistence will be indefinite, which seems unfeasible, so perhaps integration with a limited-resource account is necessary.

Humans' spatial representations enable navigation and reaching to targets above the ground plane, even without direct perceptual support. Such abilities are inconsistent with an impoverished representation of the third dimension. Features that differentiate humans from most terrestrial animals, including raised eye height and arms dedicated to manipulation rather than locomotion, have led to robust metric representations of volumetric space.

Though it draws on the grammatical metaphor of person (first, third, second) in terms of representations, Schilbach et al.'s target article does not consider an orthogonal line of evidence for the centrality of interaction to social cognition: the many grammatical phenomena, some widespread cross-linguistically and some only being discovered, which are geared to supporting real-time interaction. My commentary reviews these, and the contribution linguistic evidence can make to a fuller account of social cognition.

We show that Kurzban et al.'s approach illuminates the relationship between religion and self-control. Whereas resource-depletion theorists suggest religion replenishes self-control resources (“strength”), we submit that religious cues make people feel observed, giving them “reason” to persevere, and we describe an experiment that supports our interpretation. Finally, we question the claim that subjective fatigue is a signal to redeploy resources.

Synthetic approaches to social interaction support the development of a second-person neuroscience. Agent-based models and psychological experiments can be related in a mutually informing manner. Models have the advantage of making the nonlinear brain–body–environment–body–brain system as a whole accessible to analysis by dynamical systems theory. We highlight some general principles of how social interaction can partially constitute an individual's behavior.

The target article does not consider neural data on primate spatial representations, which we suggest provide grounds for believing that navigational space may be three-dimensional rather than quasi–two-dimensional. Furthermore, we question the authors' interpretation of rat neurophysiological data as indicating that the vertical dimension may be encoded in a neural structure separate from the two horizontal dimensions.

When do humans become moral beings? This commentary draws on developmental psychology theory to expand the understanding of early moral behaviours. We argue that by looking at a broader range of other-oriented acts than what has been considered by Baumard et al., we can find support for the mutualistic approach to morality even in early instances of other-oriented behaviours.