We focus on two problems with the evolutionary scenario proposed: (1) It bypasses the question of the origins of the communicative and semiotic features that make language distinct from, say, pleasant but meaningless sounds. (2) It does little to explain the absence of language in, for example, chimpanzees: Most of the selection pressures invoked apply just as strongly to chimps. We suggest how these problems could possibly be amended.

Keller & Miller (K&M) make a persuasive case for the role of mutation-selection balance in the persistence of such disorders as schizophrenia. However, there is evidence relating illness liability to creativity, which seems to imply balancing selection. I argue for a hybrid position, where schizotypal personality traits can have fitness advantages or disadvantages, with mutational load and neurodevelopmental conditions determining which outcome is observed.

Erdelyi distinguishes between cognitive and emotional forms of repression, but argues that they use the same general mechanism. His discussion of experimental memory findings, on the one hand, and clinical examples, on the other, does indeed indicate considerable overlap. As an in-between level of evidence, research findings on emotion in neuroscience, as well as experimental and social/personality psychology, further support his argument.

Humans are, by design, imperfect experimentalists. The cost of testing each step of a process exceeds the benefit of knowing which steps can be eliminated. To an outsider who knows which steps are superfluous, the actors appear superstitious, even ridiculous. Nonetheless, the exact duplication of all steps is rational for the imperfect experimentalist. The case of ritual in autism illustrates this point.

The proposition that selective advantages of linguistic skills have contributed to shifts in ontogenetic landmarks of human life histories in early Homo sapiens is weakened by neglecting alternative mechanisms of life history evolution. Moreover, arguments about biological continuity through sweeping comparisons with nonhuman primates do not support various assumptions of this scenario.

Numerous sex differences in obsessive-compulsive disorder (OCD) instantiations are likely universal, as the associated evolutionary threats and concerns onto which they map were differentially important to the two sexes. Hence, although some ritualized behaviors or thoughts are indeed culture-specific, others are both culturally and temporally invariant as they are rooted in universal Darwinian etiologies (e.g., the sex differences in OCD symptomatology posited here).

Erdelyi's dialectical repression theory attempts to reconcile what appear to be incompatible perspectives in the contentious area of memory for trauma. He partially succeeds and makes a strong case that repression is “an empirical fact,” but makes a weaker case that distortions and omissions are due to the same mechanism and that recovered memories are necessarily unreliable. Available data do not suggest that the return of the repressed is any less accurate than the return of the non-repressed.

The only commonality between the various psychiatric disorders is that they reflect contemporary problematic behaviors. Some psychiatric disorders have a substantial genetic component, whereas others are essentially shaped by prevailing environmental factors. Because psychiatric ailments are so heterogeneous, any universal explanation of mental illness is not likely to have any clinical or theoretical utility.

Different aspects of people's interactions with money are best conceptualized using the drug and tool theories. The key question is when these models of money are most likely to guide behavior. We suggest that the Drug Theory characterizes motivationally active uses of money and that the Tool Theory characterizes behavior in motivationally cool situations.

Ontogeny, specifically the role of language in the human family now and in prehistory, is central to Locke & Bogin's (L&B's) thesis in a compelling way. The unique life-history stages of childhood and adolescence, however, must be interpreted not only against an exceptionally high quality human infancy but also in light of the evolution of co-constructed, emotionally based communication in ape, hominid, and human infancy.

Money is a specifically human incentive. However, functional imaging techniques bring striking evidence that neural circuits pertaining to more “natural” addictive and rewarding processes are involved in response to monetary reward. Main results are evoked here, with specific brain responses demonstrated along the different stages of the process.

The forgetting and remembering phenomena that Erdelyi outlines here have little to do with the concept of repression. None of the research that he describes shows that it is possible for people to repress (and then recover) memories for entire, significant, and potentially emotion-laden events. In the absence of scientific evidence, we continue to challenge the validity of the concept of repression.

Grouping severe mental disorders into a global category is likely to lead to a “theory of everything” which forcefully explains everything and nothing. Speculation even at the phenotypic level of the single disorder cannot be fruitful, unless specific and testable models are proposed. Inclusive fitness must be incorporated in such models.

We suggest that morbid jealousy falls on the extreme end of a jealousy continuum. Thus, many features associated with normal jealousy will be present in individuals diagnosed with morbid jealousy. We apply Boyer & Lienard's (B&L's) prediction one (P1; target article, sect. 7.1) to morbid jealousy, suggesting that fitness-related life-cycle dimensions predict sensitivity to cues, and frequency, intensity, and content of intrusive thoughts of partner infidelity.

If Tool Theory is buttressed by fundamental concepts of conditioned reinforcement and extinction, a dependence on Drug Theory may not be necessary.

The consideration of humans going through sensitive periods of life, such as childhood and the early postpartum, may be helpful in understanding the cognitive and evolutionary puzzle of human rituals. During such periods, certain brain systems may mediate an increased susceptibility to learn new behaviors, rational or irrational.

Only by misconstruing the term performative are the authors able to argue that males surpass females in performative applications of language. Linguistic performatives are not costly displays of quality, and syntax cannot be explained as an outcome of behavioural competition between pubertal males. However, there is room for a model in which language co-evolves with the unique human life-history stage of adolescence.

Recent empirical work indicates that reduced autobiographical memory specificity can act as an avoidant processing style. By truncating the memory search before specific elements of traumatic memories are accessed, one can ward off the affective impact of negative reminiscences. This avoidant processing style can be viewed as an instance of what Erdelyi describes as the “subtractive” class of repressive processes.

To the evolutionarily oriented clinical psychiatrist, the discipline of behavioural ecology is a fertile basic science. Human psychology discusses variation in terms of means, standard deviations, heritabilities, and so on, but behavioural ecology deals with mutually incompatible alternative behavioural strategies, the heritable variation being maintained by negative frequency-dependent selection. I suggest that behavioural ecology should be included in the interdisciplinary dialogue recommended by Keller & Miller (K&M).

Lea & Webley's (L&W's) non-exclusive distinction between tool-like and drug-like motivators is insufficiently discriminating to say much about money that is useful, as the distinction's equivocal application to sex, food, and drugs shows. Further, it appears as though the motivations of problem gamblers are non-metaphorically like those of drug addicts.