Language processing changes with the knowledge and use of two languages. The advantage of being bilingual comes at the expense of increased processing demands and processing costs. I suggest considering bilingual complexity including these demands and costs. The proposed model claims effortless monolingual processing. By integrating individual and situational variability, the model would lose its idealistic touch, even for monolinguals.

A method is proposed where static patterns or snapshots of cortical activity that could be stored as hyperassociative indices in hippocampus can subsequently be retrieved and reinjected into the neocortex in order to enable neocortex to then proceed to unfold the corresponding sequence, thus implementing an index-based sequence memory storage and retrieval capability.

McCullough et al. hypothesize that evolution has selected mechanisms for revenge to deter harms and for forgiveness to preserve valuable relationships. However, in highly dependent relationships, the more adaptive course of action may be to remain unaware of the initial harm rather than risk alienating a needed other. We present a testable model of possible victim responses to interrelational harm.

In important ways, Clark's “hierarchical prediction machine” (HPM) approach parallels the research agenda we have been pursuing. Nevertheless, we remain unconvinced that the HPM offers the best clue yet to the shape of a unified science of mind and action. The apparent convergence of research interests is offset by a profound divergence of theoretical starting points and ideal goals.

Using representative data from 55 nations, I show that individual level wealth interacts with climate in predicting individual happiness but not postmaterialism values. I propose that more research is needed to identify (a) the specific mechanisms of how wealth buffers climatic demands at the individual level and (b) the neurocognitive and physiological reactions of individuals situated in different ecological niches.

Although the art-historical context of a work of art is important to our appreciation of it, it is our knowledge of that history that plays causal roles in producing the experience itself. This knowledge is in the form of memories, both semantic memories about the historical circumstances, but also episodic memories concerning our personal connections with an artwork. We also create representations of minds in order to understand the emotions that artworks express.

We studied the world's most distinguished experts in the use of mnemonic techniques: the top participants of the World Memory Championships. They neither feel the use of mnemonics to be dreamlike, nor does their REM sleep differ from mnemonic-naive control subjects. Besides these empirical data, also theoretical considerations contradict an isomorphism between features of REM sleep dreaming and mnemonic principles.

This commentary describes the use of ecological priming methods to address the limitations of the correlational research discussed in the target article. We provide examples from our own work on cultural tightness–looseness to illustrate how we can bring ecological and societal conditions into the laboratory in order to study the impact of ecological threats on psychological processes experimentally.

A radical interpretation of the predictive coding approach suggests that the mind is “seamless” – that is, that cancellation of error signals can propagate smoothly from highest to lowest levels of the control hierarchy, dissolving a distinction between belief and perception. Delusions of alien control provide a test case. Close examination suggests that while they are evidence of predictive coding within the cortex, they are not evidence for the seamless interpretation.

The target article's evolutionary approach provides an excellent framework for understanding when and why people retaliate or forgive. We argue that recent findings on the basic processes in forgiveness – particularly, the role of executive control – can further refine the authors' proposed model. Specifically, the lack of executive control may restrict the explanatory power of relationship value and exploitation risk.

Embedding theories of language production and comprehension in theories of action-perception is realistic and highlights that production and comprehension processes are interleaved. However, layers of internal models that repeatedly predict future linguistic actions and perceptions are implausible. I sketch an ecological alternative whereby perceiver/actors are modeled as dynamical systems coupled to one another and to the environment.

The target article presents a thought-provoking approach to the relation of neuroscience and art. However, at least two issues pose potential difficulties. The first concerns whether “art appreciation” is a coherent topic for scientific study. The second concerns the degree to which processing fluency can explain aesthetic feeling or may simply be one component of a more complex account.

Classic traditions have linked dreams to memory (e.g., “dreaming is another kind of remembering” [Freud 1918/1955]) and modern notions like implicit memory subsume dreaming by definition. Llewellyn develops the more specific thesis that rapid eye movement (REM) dreams, because of their similarities to mnemonic techniques, have the function of elaboratively encoding episodic memories. This proposal is premature, requiring exigent testing. Other analogs of dreams, for example, jokes, do not invoke function but do contribute to dream science.

This commentary discusses dozens of ecologically powerful social-psychological experiments from the1960s and 1970s, which are highly relevant especially for predicting the consequences of revenge. McCullough et al. omitted this work – perhaps because of its misclassification as “catharsis” research. The findings are readily accommodated by Konečni's anger-aggression bidirectional-causation (AABC) model and can be usefully incorporated in an adaptationist view of revenge.

A quantitative theory of reproductive decisions (Gowaty & Hubbell 2009) says that individuals use updated priors from constantly changing demographic circumstances to predict their futures to adjust actions flexibly and adaptively. Our ecological/evolutionary models of ultimate causes seem consistent with Clark's ideas and thus suggest an opportunity for a unified proximate and ultimate theory of Bayesian animal brains, senses, and actions.

Given Van de Vliert's impressive dataset and prognoses, I will discuss three limitations. First, the evolutionary argument does not adequately take into account how political changes influence freedoms. Second, the operationalizations of needs and freedoms are limited and questionable. Third, a direct relationship between climate, monetary resources, and psychological variables is a simplification neglecting various intervening variables.

We discuss how the psycho-historical framework can be profitably applied to artistic production, facilitating a synthesis of perception-based and knowledge-based perspectives on realistic observational drawing. We note that artists' technical knowledge itself constitutes a major component of an artwork's historical context, and that links between artistic practice and psychological theory may yet yield conclusions in line with universalist perspectives.

At the core of Pickering & Garrod's (P&G's) theory is a monitor that uses forward models. I argue that this account is challenged by neuropsychological findings and visual world eye-tracking data and that it has two conceptual problems. I propose that conflict monitoring avoids these issues and should be considered a promising alternative to perceptual loop and forward modeling theories.

There is little doubt that predictive coding is an important mechanism in language processing–indeed, in information processing generally. However, it is less clear whether the action system is the source of such predictions during perception. Here I summarize the computational problem with motor prediction for perceptual processes and argue instead for a dual-stream model of predictive coding.

We review two subjective (mis)perceptions that influence revenge and forgiveness systems. Individual differences predict more (e.g., narcissism) or less (e.g., empathy) revenge, with the opposite pattern for forgiveness. Moreover, differences in victim versus perpetrator perceptions can influence revenge and forgiveness systems, perpetuating never-ending cycles of revenge. These two examples point to the need for theories of revenge and forgiveness to address the role of cognitive and motivational biases in the functionality of such behavioral responses.