Based on increasing dream intensity and alterations in neurophysiological activity from waking, through NREM to REM sleep, dreaming appears to correlate with sustained midbrain dopaminergic and basal forebrain cholinergic, in conjunction with decreasing brainstem 5-HT and noradrenergic neuronal activities. This, model, with features in common with the modulatory transmitter models of Hobson et al. and Solms, is consistent with some clinical observations on drug induced alterations in dreaming and transmitter correlates of delusions.

[Hobson et al.; Solms]

A research program is announced, and initial, exciting progress described. Many inference problems, poorly modeled by some traditional approaches, are surprisingly well handled by kinds of simple-minded Bayesian approximations. Fuller Bayesian approaches are typically more accurate but rarely are they either fast or frugal. Open issues include codifying when to use which heuristic and to give detailed evolutionary explanations.

The metaphor of “behavioral momentum” exemplifies modernism at its best and follows in the wake of countless other applications of Newtonian mechanics and “the machine metaphor” to virtually every aspect of the human condition. Modernism, however, has fallen on hard times. Some of the chief reasons why are implicit in the target article by Nevin & Grace.

The soundness of Chow's (1996; 1998a) argument depends on the soundness of his assertion that statistical significance may be understood to signify that chance may be excluded as the reason for results. The examples and arguments provided here show that statistical significance signifies no such thing.

Gangestad & Simpson's central premise regarding individual differences is applied to their facultative-argument based on mating- strategy, for individual differences in susceptibility to contextual effects. Some individuals may be relatively fixed strategists who are rather unresponsive to context when it comes to mating, whereas others, perhaps most, may be, as G&S propose, flexible strategists.

The emphasis on individual differences in evolutionary theories is important and has not received adequate attention. Strategic Pluralism makes a major contribution by addressing these issues, but like other evolutionary models (e.g., game theory) does not articulate the specific mechanisms underlying strategy selection. Specification of such mechanisms is an essential next step in the development of these models.

Dreams represent threat, but appear to do so metaphorically more often than realistically. The metaphoric representation of threat allows it to be conceptualized in a manner that is constant across situations (as what is common to all threats begins to be understood and portrayed). This also means that response to threat can come to be represented in some way that works across situations. Conscious access to dream imagery, and subsequent social communication of that imagery, can facilitate this generalized adaptive process, by allowing the communicative dreamer access to the problem solving resources of the community.

[Revonsuo; Solms]

That Haig and Sohn find the hypothetico-deductive approach wanting in different ways shows that multiple conditional syllogisms are being used in different stages of theory corroboration in the Popperian approach. The issues raised in the two commentaries assume a different complexion when certain distinctions are made.

The simple heuristics that may indeed usually make us smart–or at least smart enough–in contexts of individual choice will sometimes make us dumb, especially in contexts of social choice. Here each individual choice (or vote) has little impact on the overall choice, although the overall choice is compounded out of the individual choices. I use an example (risk aversion) to illustrate the point.

Nevin & Grace's primary argument against theory and research on behavioral momentum is that preference and resistance to change may not covary. The method for evaluating preference and resistance to change seems problematic. Moreover, the theory fails to account convincingly for effects of average overall time to primary reinforcement on choice and preference for unsegmented schedules.

The AIM model represents an original and comprehensive example of how changes in conscious states can be reconciled with specific neurophysiological factors. However, further elucidation of the biological parameters necessary to define a specific space-state relationship should be considered.

[Hobson et al.; Solms]

I investigate whether heuristics similar to those studied by Gigerenzer and his co-authors can apply to the problem of finding a suitable heuristic for a given problem. I argue that not only can heuristics of a very similar kind apply but they have the added advantage that they need not incorporate specific trade-off parameters for balancing the different desiderata of a good decision-procedure.

The research Nevin & Grace report is impressive in its integrative power, but it also shows the current limits of operant theory: There is tremendous concentration on understanding how existing behavioral relations are modulated in rate or time allocation, but little on dealing with the origin of the behavioral relations themselves. Specifying what should count as a behavioral unit will require source principles sensitive to the composition of the units being related.

Gangestad & Simpson make a major contribution by highlighting the importance of mate choice for good genes, the costs of alternative strategies, and tradeoffs inherent in human mating. By downplaying sex differences and ignoring the nongenetic adaptive benefits of short term mating, however, they undermine their goal of “strategic pluralism” by presenting a theory devoid of many documented complexities of human mating.

The adaptive trade-offs between long- and short-term matings may be mediated or at least reflected partially by the trade-offs between the relative reinforcement obtained through a greater frequency of intercourse (typically greater among cohabitants) versus a greater frequency of partner change. The differing correlates of each approach and meshing with the Sexual Strategies Theory of Gangestad & Simpson are discussed.

Certain features of Stage NREM sleep – for example, rhythmic voltage oscillation in thalamic neurons – are physiologically inhospitable to “REM sleep processes.” In Stage 2, the sleep spindle and its refractory period must limit the incursion of “covert REM,” and thus the extent of REM-like cognition. If these hyperpolarization-dependent events also inform Stage NREM cognition, does a “1-gen” model suffice to account for REM-NREM differences?

[Nielsen]

The notion of ecological rationality, although plausible, does not readily lead to testable predictions. This is illustrated with respect to heuristics in syllogistic reasoning. Several possible heuristics have been proposed but ecological rationality does not appear to offer a sensible rationale for choosing between these.

Metaphors “highlight and hide” different aspects of phenomena. A behavioral economic metaphor for excessive consumption highlights the contextual features of behavioral-environment relations. Can the behavioral momentum metaphor generate a representation of context that is at least as useful as that generated by behavioral economics? Maybe, maybe not; or maybe a mixed metaphor will do a better job than either alone.

Data support the claim from the target article that women, both cross-culturally and historically, have employed a variety of mating strategies, marrying but also engaging in short-term unions. But those strategies appear to be practiced simultaneously and not conditionally as Gangestad & Simpson propose, a finding consistent with assumed constraints on the potential reproductive success of females.

This commentary questions the claim that Take-The-Best provides a cognitively more plausible account of cue utilisation in decision making because it is faster and more frugal than alternative algorithms. It is also argued that the experimental evidence for Take-The-Best, or non-integrative algorithms, is weak and appears consistent with people normally adopting an integrative approach to cue utilisation.