Dreaming in sleep must depend on the activity of the brain as does cognition and memory in wakefulness. Yet our understanding of the physiological subtleties of state differences may still be too primitive to guide theories adequately in these areas. One can state nonetheless unequivocally that the brain in REM is poorly equipped to practice for eventualities of wakefulness through dreaming, or for consolidating into memory the complex experiences of that state.

[Hobson et al., Nielsen, Solms, Vertes & Eastman, Revonsuo]

This review of Gigerenzer, Todd, and the ABC Research Group's Simple heuristics that make us smart focuses on the role of heuristics in discovery, invention, and hypothesis-testing and concludes with a comment on the role of heuristics in population growth.

Theorists of learning, regulation, and evolution explain behavior using remarkably different concepts because of pressures toward specialization, a focus on testing simple causal theories that underconceptualize the contributions of the organism and its environment, and the absence of a working model capable of surviving in a complex environment. We add suggestions for the development and testing of such a model.

The absence of a clear influence of an animal's behavioral responses to Hebbian associative learning in the cerebral cortex requires some changes in the Hebbian learning rules. The participation of the brain monoaminergic systems in Hebbian associative learning is considered.

That PTSD nightmares are highly realistic threat simulations triggered by trauma is difficult to reconcile with the disturbed, sometimes debilitating sleep and waking functioning of PTSD sufferers. A theory that accounts for fundamental forms of imagery other than threat scenarios could explain the selection of many more adaptive human functions – some still pertinent to survival today. For example, interactive characters, a virtually ubiquitous form of dream imagery, could be simulations of attachment relationships that aid species survival in many different ways.

[Revonsuo]

When a distinction is drawn between “total” knowledge and “problem-specific” knowledge, it is seen that successful users of the recognition heuristic have more problem-specific knowledge than people unable to exploit this heuristic. So it is not ignorance that makes them smart, but knowledge.

An important measure of the validity and utility of basic behavioral research is the extent to which it can be applied in real life. Basic research on behavioral momentum and the model unifying choice and resistance to change (Nevin & Grace 1999) has stimulated the development of behavioral technologies aimed at increasing the persistence of adaptive behavior and decreasing maladaptive choices.

Reactions to the target article included requests for extensions and elaborations of the schema we proposed and discussions of apparent shortcomings of our approach. In general, we welcome suggestions for extension of the schema to additional kinds of social behavior and to forms of learning other than Pavlovian conditioning. Many of the requested elaborations of the schema are consistent with our approach, but some may limit its generality. Many of the apparent shortcomings that commentators discussed do not seem problematic. Our schema encourages a broad view of the behavioral consequences of Pavlovian conditioning – including learned modifications of responding to the unconditioned stimulus. Costs and benefits addressed by our schema are the long-range reproductive consequences of learning – not the immediate reinforcing consequences of particular conditioned responses. Our approach allows the evolution of learning to yield maladaptive behavior and can be extended to characterize dynamic social interactions. We clarify that ours is not a homeostatic model involving ideal set points, and we clarify and defend our application of Pavlovian concepts to the analysis of social play.

In a recent BBS target article, MacNeilage (1998) presents what he claims to be the only theory that can account for the evolution of language. However, major portions of his target article basically repeat and in many respects are identical to the theories of language evolution and development first proposed and detailed by the present commentator.

We clarify the arguments in Neural organization: Structure, function, and dynamics, acknowledge important contributions cited by our critics, and respond to their criticisms by charting directions for further development of our integrated approach to theoretical and empirical studies of neural organization. We first discuss functional organization in general (behavior versus cognitive functioning, the need to study body and brain together, function in ontogeny and phylogeny) and then focus on schema theory (noting that schema theory is not just a top-down theory and discussing the transition from action-oriented perception to cognition). We then turn to dynamical organization, with a focus first on neural modeling and dynamics (clarifying the multiple functions of neurons and brain regions, and looking further at various forms of dynamics) and second on learning, development, and self-organization (looking at monoaminergic systems, reinforcement, self-organization, postnatal development, and disease). We close with a brief philosophical discussion of postmodernism and reductionism.

This commentary considers factors that may account for the inconsistency between the behavioral momentum formulation and the partial reinforcement extinction effect. The method of testing, the variability of the schedule, the nature of the response-contingency, and response effort are considered. Some applications to real-world problems are also discussed.

During human evolutionary history, there were “trade-offs” between expending time and energy on child-rearing and mating, so both men and women evolved conditional mating strategies guided by cues signaling the circumstances. Many short-term matings might be successful for some men; others might try to find and keep a single mate, investing their effort in rearing her offspring. Recent evidence suggests that men with features signaling genetic benefits to offspring should be preferred by women as short-term mates, but there are trade-offs between a mate's genetic fitness and his willingness to help in child-rearing. It is these circumstances and the cues that signal them that underlie the variation in short- and long-term mating strategies between and within the sexes.

Johnson-Laird & Byrne (1991; 1993) present a theory of human deductive reasoning based on the notion of mental models. Unfortunately, the theory is incomplete. The present commentary argues that pragmatic considerations, particularly of the type discussed in Sperber and Wilson (1995), can complement the theory.

New data are presented showing excellent replicability and test-retest reliability of REM sleep findings from functional brain imaging studies in healthy subjects on which newer brain-based models of human dreaming have been constructed. Preliminary region-of-interest findings related to bottom-up versus dissociable brain systems mediating REM sleep and dreaming are also presented.

[Hobson et al.; Solms]>

Humans are incapable of acting as utility maximisers. In contrast, the evolutionary process had considerable time and computational power to select optimal heuristics from a set of alternatives. To view evolution as the optimising agent has revolutionised game theory. Gigerenzer and his co-workers can help us understand the circumstances under which evolution and learning achieve optimisation and Nash equilibria.

Simple heuristics and regression models make different assumptions about behaviour. Both the environment and judgment can be described as fast and frugal. We do not know whether humans are successful when being fast and frugal. We must assess both global accuracy and the costs of Type I and II errors. These may be “smart heuristics that make researchers look simple.”

Behavioral momentum is a part of the larger field of behavioral dynamics concerned with modeling conditions controlling changes in behavior. The analogy of behavioral momentum to Newtonian and Einsteinian dynamics is briefly treated along with additional physical intuitions related to resistance to behavior change and preference.

Gangestad & Simpson's (G&S's) analysis of strategic pluralism is welcomed as a balance to the current emphasis on between-sex variation. It could have been clarified by acknowledging the extent to which males and females represent fundamentally different mating strategies, since this affects how we view within-sex strategic variation. The distinction between conditional and alternative strategies could also have been highlighted.

The deactivation of the dorsolateral prefrontal cortex is likely to be essential for generating some characteristics of the dream. The heterogeneous nature of NREM sleep makes it difficult to assume that there are different NREM dream triggers. Different cortical and subcortical neurophysiological conditions modulate mentation both in waking and in sleeping without any specific direct triggering factor.

[Solms]

Van der Henst argues that the theory of mental models lacks a pragmatic component. He fills the gap with the notion that reasoners draw the most relevant conclusions. We agree, but argue that theories need an element of “nondeterminism.” It is often impossible to predict either what will be most relevant or which particular conclusion an individual will draw.