The proposed dynamic systems model of emotion generation indeed appears considerably more plausible and descriptively adequate than traditional linear models. It also comes much closer to the complex interactions observed in neurobiological research. The proposals regarding self-organization in emerging appraisal-emotion interactions are thought-provoking and attractive. Yet, at this point they are more in the nature of promises than findings, and are clearly in need of corroborating psychological evidence or demonstrated theoretical desirability.

Dynamic systems theory (DS) provides tools for exploring how simpler elements can interact to produce complex psychological configurations. It may, as Lewis demonstrates, provide means for explicating relationships between two reductionist approaches to overlapping sets of phenomena. The result is a description of psychological phenomena at a level that begins to achieve the richness we would hope to achieve in examining psychological life as it is experienced and explored in psychoanalysis.

Lewis proposes a “reconceptualization” of how to link the psychology and neurobiology of emotion and cognitive-emotional interactions. His main proposed themes have actually been actively and quantitatively developed in the neural modeling literature for more than 30 years. This commentary summarizes some of these themes and points to areas of particularly active research in this area.

Lewis makes a strong case for the interdependence and integration of emotion and cognitive processes. Yet, these processes exhibit considerable independence in early life, as well as in certain psychopathological conditions, suggesting that the capacity for their integration emerges as a function of development. In some circumstances, the concept of highly interactive emotion and cognitive systems seems a viable alternative hypothesis to the idea of systems integration.

Lewis has missed an excellent opportunity to concisely demonstrate that a dynamical system can provide a bridge between emotion theory and neurobiology.

Lewis emphasizes the role of theta oscillations in emergent coupling among neural subsystems during emotionally relevant tasks or situations. Here I present some recent data on the relationship of rhythmic neuronal discharge in the supramammillary nucleus and the large-scale theta oscillations in the limbic system which provide support to many of his ideas regarding vertical integration in dynamic systems.

Lewis discusses the dynamic mechanisms of emotional-cognitive integration. I argue that he neglects the self and its neural correlate. The self can be characterized as an emotional-cognitive unity, which may be accounted for by the interplay between anterior and posterior medial cortical regions. I propose that these regions form an anatomical, physiological, and psychological unity, the cortical midline structures (CMSs).

Emotion-science without basic brain-science is only superficially satisfying. Dynamic systems approaches to emotions presently provide a compelling metaphor that raises more difficult empirical questions than substantive scientific answers. How might we close the gap between theory and empirical observations? Such theoretical views still need to be guided by linear cross-species experimental approaches more easily implement in the laboratory.

Does Lewis imply that brain processes might be used to replace an as-yet-unavailable substantive organismic neuropsychology? To counteract this reductionist idea I argue for distinguishing between affects and emotions, and discuss a real-life example of implicit emotional appraisal. Failure to use organismic units of processing such as schemes or schemas makes the bridging attempt fall under a reductionist “mereological fallacy.”

By emphasizing nonlinear dynamics between appraisal and emotions, Lewis's model provides a valuable platform for integrating psychological and neural perspectives on the emotion-cognition interface. In this commentary, I discuss the role of neuroscience in shaping new conceptualizations of emotion and the putative role of theta oscillation within frontocingulate pathways in depression, a syndrome in which emotion-cognition relations are dysfunctional.

Although emotion may subserve social function, as with anger-maintaining dominance, emotions are more than variant cognitions. Anger promotes risk-taking, attention-narrowing, and cognitive impairment. The proposition that appraised “blameworthiness” is necessary for anger excludes young children's anger as well as adults' pain-induced anger. To be complete, any systems model of anger must account for its temporal characteristics, including escalation and persistence.

The issues addressed in this commentary include: (1) the appropriate conceptualization of “appraisal”; (2) the nature and unfolding of emotional episodes over time; (3) the interrelationships between the dynamic elements of the appraisal process and their effects on other emotion components, as well as repercussions on ongoing appraisal in a recursive process; and (4) the use of brain research to constrain and inform models of emotion.

Lewis describes the developmental core of dynamic systems theory. I offer recent data from developmental neuroscience on the sequential experience-dependent maturation of components of the limbic system over the stages of infancy. Increasing interconnectivity within the vertically integrated limbic system allows for more complex appraisals of emotional value. The earliest organization of limbic structures has an enduring impact on all later emotional processing.

Lewis makes a compelling case for a dynamical systems approach to emotion and neurobiology. These models involve both excitatory and inhibitory processes. It appears that a critical role for inhibitory processes is implied but not emphasized in Lewis's model. We suggest that a greater understanding of inhibitory processes both at the psychological and neurobiological levels might further enhance Lewis's model.

Considered in relation to the component brain systems of appraisal-emotion interactions, dynamical systems theory blurs the divisions that seem obvious in a psychological analysis, such as between arousal, emotion, and appraisal. At the same time, the component brain mechanisms can themselves be seen to be incomplete as units of analysis, making sense only in the context of the whole organism.

Lewis proposes a solution for bridging the gap between cognitive-psychological and neurobiological theories of emotion in terms of dynamic systems modeling. However, an important brain network is absent in his account: the neuroendocrine system. In this commentary, the dynamic features of the cross-talk between the hypothalamic-pituitary-adrenal (HPA) and gonadal (HPG) axes are discussed within a triple-balance model of emotion.

A dynamic systems (DS) approach uncovers important connections between emotion and neurophysiology. It is critical, however, to include a developmental perspective. Strides in the understanding of emotional development, as well as the present use of DS in developmental science, add significantly to the study of emotion. Examples include stranger fear during infancy, intermodal perception of emotion, and development of individual emotional systems.

We present a dynamical model of interaction between recognition memory and affect, focusing on the phenomenon of “warm glow of familiarity.” In our model, both familiarity and affect reflect quick monitoring of coherence in an attractor neural network. This model parsimoniously explains a variety of empirical phenomena, including mere-exposure and beauty-in-averages effects, and the speed of familiarity and affect judgments.

The target article developed a dynamic systems framework that viewed the causal basis of emotion as a self-organizing process giving rise to cognitive appraisal concurrently. Commentators on the article evaluated this framework and the principles and mechanisms it incorporated. They also suggested additional principles, mechanisms, modeling strategies, and phenomena related to emotion and appraisal, in place of or extending from those already proposed. There was general agreement that nonlinear causal processes are fundamental to the psychology and neurobiology of emotion.

The Sociosexual Orientation Inventory (SOI; Simpson & Gangestad 1991) is a self-report measure of individual differences in human mating strategies. Low SOI scores signify that a person is sociosexually restricted, or follows a more monogamous mating strategy. High SOI scores indicate that an individual is unrestricted, or has a more promiscuous mating strategy. As part of the International Sexuality Description Project (ISDP), the SOI was translated from English into 25 additional languages and administered to a total sample of 14,059 people across 48 nations. Responses to the SOI were used to address four main issues. First, the psychometric properties of the SOI were examined in cross-cultural perspective. The SOI possessed adequate reliability and validity both within and across a diverse range of modern cultures. Second, theories concerning the systematic distribution of sociosexuality across cultures were evaluated. Both operational sex ratios and reproductively demanding environments related in evolutionary-predicted ways to national levels of sociosexuality. Third, sex differences in sociosexuality were generally large and demonstrated cross-cultural universality across the 48 nations of the ISDP, confirming several evolutionary theories of human mating. Fourth, sex differences in sociosexuality were significantly larger when reproductive environments were demanding but were reduced to more moderate levels in cultures with more political and economic gender equality. Implications for evolutionary and social role theories of human sexuality are discussed.