Recent studies in human and nonhuman primates demonstrate that auditory objects, including speech sounds, are identified in anterior superior temporal cortex projecting directly to inferior frontal regions and not along a posterior pathway, as classically assumed. By contrast, the role of posterior temporal regions in speech and language remains largely unexplained, although a concept of vocal gestures may be helpful.

To conclude that language evolved from vocalizations, through gestures, then back to vocalizations again, one must first reject the simpler hypothesis that language evolved from prelinguistic vocalizations. There is no reason to do so. Many studies – not cited by Arbib – document continuities in behavior, perception, cognition, and neurophysiology between human speech and primate vocal communication.

The notion that manual gestures played an important role in the evolution of human language was strengthened by the discovery of mirror neurons in monkey area F5, the proposed homologue of human Broca's area. This idea is central to the thesis developed by Arbib, and lending further support to a link between motor resonance mechanisms and language/communication development is the case of autism and congenital blindness. We provide an account of how these conditions may relate to the aforementioned theory.

Perhaps the greatest evolutionary advantage conferred by spoken language was its ability to communicate mentalistic concepts, rather than just extending the vocabulary of action already served by an imitation function. An appreciation that the mirror-neuron system served a simple mentalising function before gestural communication sets Arbib's theory in a more appropriate social cognitive context.

Our tolerance for, and promotion of, linguistic irregularity is a key arbitrator between Arbib's proposal that holistic protolanguage preceded culturally imposed compositionality, and the standard view that discrete units with word-like properties came first. The former, coupled with needs-only analysis, neatly accounts for the second-order linguistic complexity that is rationalised as fuzzy grammaticality, subclass exception, and full irregularity.

Our computational studies of infant language learning estimate the inherent difficulty of Arbib's proposal. We show that body language provides a strikingly helpful scaffold for learning language that may be necessary but not sufficient, given the absence of sophisticated language in other species. The extraordinary language abilities of Homo sapiens must have evolved from other pressures, such as sexual selection.

Challenges for extending the mirror system hypothesis include mechanisms supporting planning, conversation, motivation, theory of mind, and prosody. Modeling remains relevant. Co-speech gestures show how manual gesture and speech intertwine, but more attention is needed to the auditory system and phonology. The holophrastic view of protolanguage is debated, along with semantics and the cultural basis of grammars. Anatomically separated regions may share an evolutionary history.

Efforts to bridge emotion theory with neurobiology can be facilitated by dynamic systems (DS) modeling. DS principles stipulate higher-order wholes emerging from lower-order constituents through bidirectional causal processes – offering a common language for psychological and neurobiological models. After identifying some limitations of mainstream emotion theory, I apply DS principles to emotion–cognition relations. I then present a psychological model based on this reconceptualization, identifying trigger, self-amplification, and self-stabilization phases of emotion-appraisal states, leading to consolidating traits. The article goes on to describe neural structures and functions involved in appraisal and emotion, as well as DS mechanisms of integration by which they interact. These mechanisms include nested feedback interactions, global effects of neuromodulation, vertical integration, action-monitoring, and synaptic plasticity, and they are modeled in terms of both functional integration and temporal synchronization. I end by elaborating the psychological model of emotion–appraisal states with reference to neural processes.

Lewis's dynamic systems approach is a refreshing change from the reflexology of most neuroscience, but it could go a step further: It could include the expected rewardingness of an emotion in the recursive feedback loop that determines whether the emotion will occur. Two possible objections to such a model are discussed: that emotions are not deliberate, and that negative emotions should lose out as instrumental choices.

This commentary argues that one specific but central concept in Lewis's theory, circular causality, is fundamentally flawed and should be discarded – first, because it does not make theoretical sense, and, second, because it leads to problems in practice, such as confounding the interaction between different systems with the relationship between different levels of analysis of a single system.

Bridging between psychological and neurobiological systems requires that the system components are closely specified at both the psychological and brain levels of analysis. We argue that in developing his dynamic systems theory framework, Lewis has sidestepped the notion of a psychological level systems model altogether, and has taken a partisan approach to his exposition of a brain-level systems model.

Self-organizing dynamic systems (DS) modeling is appropriate to conceptualizing the relationship between emotion and cognition-appraisal. Indeed, DS modeling can be applied to encompass and integrate additional phenomena at levels lower than emotional interpretations (genes), at the same level (motives), and at higher levels (social, cognitive, and moral emotions). Also, communication is a phenomenon involved in dynamic system interactions at all levels.

Understanding how emotions emerge is difficult without determining what characteristic of the trigger actually triggers them. Knowing whether emotional experiences self-stabilize is difficult without remembering what other processes are set in play as the emotion emerges. It is not clear either that positive feedback is required for the emergence of emotion or that an attractor model captures well what is happening when an emotion arises.

Conceptual space is proposed as an intermediate representation level between the psychological and the neurobiological levels of descriptions of appraisal and emotions. The main advantage of the proposed intermediate representation is that the appraisal and emotions dynamics are described by using the terms of geometry.

This commentary makes three points: (1) There may be no clear-cut distinction between emotion and appraisal “constituents” at neural and psychological levels. (2) The microdevelopment of an emotional interpretation contains a complex microdevelopment of affect. (3) Neurophenomenology is a promising research program for testing Lewis's hypotheses about the neurodynamics of emotion-appraisal amalgams.

Lewis argues convincingly that a DS approach to emotion theory will be fruitful. He also appears to hold that there are DS principles that constitute a theory or are substantial empirical claims. I argue that this latter move is a mistake.

Lewis neglects cross-cultural data in his dynamic systems model of emotion, probably because appraisal theory disregards behavior and because anthropologists have not engaged discussions of neural plasticity in the brain sciences. Considering cultural variation in emotion-related behavior, such as grieving, indigenous descriptions of emotions, and alternative developmental regimens, such as sport, opens up avenues to test dynamic systems models.

Lewis's dynamical systems emotion theory continues a tradition including Merleau-Ponty, von Bertallanfy, and Aristotle. Understandably for a young theory, Lewis's new predictions do not follow strictly from the theory; thus their failure would not disconfirm the theory, nor their success confirm it – especially given that other self-organizational approaches to emotion (e.g., those of Ellis and of Newton) may not be inconsistent with these same predictions.

Fully interpreted, Lewis's dynamic systems modeling of emotion encompasses psychological-adaptation thinking and individual and group differences in normal and abnormal behavior. It weakens the categorical perspective in evolutionary psychology and the clinical sciences; and suggests continuity between “normal” or “abnormal” behavior in whatever way this is self and culturally constituted, although culture/linguistic factors and selfhood are neglected. Application of a dynamic systems model could improve formulation of clinical problems.

EEG evidence supports the view that each cerebral hemisphere maintains a scale-free network that generates and maintains a global state of chaos. By its own evolution, and under environmental impacts, this hemispheric chaos can rise to heights that may either escape containment and engender incontinent action or be constrained by predictive control and yield creative action of great power and beauty.