Empirical evidence of self-deception's propositional duality is not sought; philosophically relevant links between propositions proper and mind are explored instead. Speech in unison ably indicates the social grounding of such attitudinal structures. An extra-theoretical eye – with regard to cognitivism – is cast on a case of “illusory communication.” The reinforcing of lexical analysis shows Mele's approach to be in need of non-ego concepts, wherefore it lacks soundness with respect to reference.

While explaining a large proportion of any variance, accounts of the speed and accuracy of targetting movements use techniques (e.g., log transforms) that typically reduce variability before “explaining” the data. Therefore the predictive power of such accounts are important. We consider whether Plamondon's model can account for kinematics of targetting movements of clinical populations.

To describe phenomena that occur at different time scales, computational models of the brain must incorporate different levels of abstraction. At time scales of approximately 1/3 of a second, orienting movements of the body play a crucial role in cognition and form a useful computational level – more abstract than that used to capture natural phenomena but less abstract than what is traditionally used to study high-level cognitive processes such as reasoning. At this “embodiment level,” the constraints of the physical system determine the nature of cognitive operations. The key synergy is that at time scales of about 1/3 of a second, the natural sequentiality of body movements can be matched to the natural computational economies of sequential decision systems through a system of implicit reference called deictic in which pointing movements are used to bind objects in the world to cognitive programs. This target article focuses on how deictic bindings make it possible to perform natural tasks. Deictic computation provides a mechanism for representing the essential features that link external sensory data with internal cognitive programs and motor actions. One of the central features of cognition, working memory, can be related to moment-by-moment dispositions of body features such as eye movements and hand movements.

The idea of a neuromuscular synergy involving independent amplitude commands to the agonist and antagonist musculature is quite an appealing part of Plamondon's theory. One question that might be raised relates to the relative independence of the two “D” commands. Evidence is presented that suggests that the two commands might be related in sequential or simultaneous rapid aiming movements.

I agree with Mele that self-deception is not intentional deception; but I do believe that self-deception involves intentional biasing, primarily for two reasons: (1) There is a Bayesian model of self-deception that explains why the biasing is rational. (2) It is implausible that the observed behavior of self- deceivers could be generated by Mele's “blind” mechanisms.

The motor system might well use deictic strategies when subjects learn a new task. However, its not clear that Ballard et al. show this. Multiple eye-fixations may have little to do with deixis and more to do with the unfamiliarity of the task. In any case, deixis does not entail embodiment, since a disembodied Cartesian brain could use deictic strategies.

We question whether Plamondon & Alimi's model is useful in accounting for the nonsymmetrical and multiple-peaked velocity profiles observed in young and elderly subjects for ballistic aiming tasks. For these subjects, both data and observation suggest that a central representation initiates the movement in an appropriate direction but that multiple adjustments are made, both early and late, to achieve spatial accuracy.

This response addresses seven main issues: (1) alleged evidence that in some instances of self-deception an individual simultaneously possesses “contradictory beliefs”; (2) whether garden-variety self-deception is intentional; (3) whether conditions that I claimed to be conceptually sufficient for self-deception are so; (4) significant similarities and differences between self-deception and interpersonal deception; (5) how instances of self-deception are to be explained, and the roles of motivation in explaining them; (6) differences among various kinds of self- deception; (7) whether a proper conception of self-deception implies that definitive ascriptions of self-deception to individuals are impossible.

Ballard et al. show how control structures using minimal state can be made flexible enough for complex cognitive tasks by using deictic pointers, but they do so within a specific computational framework. We discuss broader implications in cognition and memory and provide biological evidence for their theory. We also suggest an alternative account of pointer binding, which may better explain their limited number.

Plamondon & Alimi propose a universal account of trajectory formation and speed/accuracy trade-off in rapid movements but fail, because: (1) the kinematic model ignores the more fundamental dynamics of movement generation, and (2) it does not capture the essential space-time constraints of movement accuracy. Hence, the modeling lacks a biologically and behaviorally principled foundation and is driven by pragmatic function fitting.

Deictic pointers allow the nervous system to exploit information in a frame that is centered on the object of interest. This processing may take place in visual or haptic space, but the information processing advantages of deictic pointing can also be applied in abstract spaces, providing the basis for analogical transfer. Simulation and behavioral results illustrating this progression from embodiment to abstraction are discussed.

British marriage statistics (N = 311,564) suggest that women of breeding age choose young men. Women past breeding age who could still be raising children extend choices to include older men. After this, women do not marry. The choices of men over 50 are restricted to women between 40 and 55: past breeding but young enough to be raising children; the few men over 50 that marry choose women in this age range.

Following the “modularity” orthodoxy of some years ago, it has traditionally been assumed that there is a clear and obvious separation between perception and cognition. Close examination of this concept, however, fails to reveal the join. Ballard et al.'s contention that the two “cannot be easily separated” is consistent with nonmodular views of the way that symbol grounding might be achieved in situated systems. Indeed, the traditional separation is viewed as unhelpful.

We show through analysis of personal advertisements that age preferences for a homosexual or lesbian partner are similar to differences found between men and women in age preferences for a opposite-sex partner. Such data call into question the claim by Kenrick & Keefe (1992) that the sex differences in age selectivity in mate selection are governed by reproductive strategies.

Even if we recognize that the delta-lognormal model provides an excellent fit to a large variety of data, the question remains as to what we actually learn from such a model, which could be seen as merely another multiparameter account? Do we welcome such an encompassing account, or do we expect to learn more from the limitations that become apparent when applying dedicated models addressing specific classes of movements?

It is unlikely that Ballard et al.'s embodiment theory has general applicability to cognition because it is based on experiments that neglect the importance of meaning, purpose, and learning in cognitive tasks. Limitations of the theory are illustrated with examples from everyday life and the results of recent experiments using cognitive and visuomotor tasks.

Information about positions, from which differences in position are computed (as proposed in the vector-integration- to-endpoint model), provides a more plausible perceptual basis for the control of goal-directed arm movements than information about distance (as proposed in the kinematic model).

Einon's data support our original claims, although not a claim she seems to assume – of reciprocal attraction between elderly men and 20-year-old women. Implicit in her commentary is an assumption that genetic predispositions are omniscient fitness maximizers. Instead, evolutionary models assume selection-fashioned psychological mechanisms that, in the context of other mechanisms and pressures in past environments, had a positive effect on fitness relative to competing alternatives. The Over & Phillips data fit with our own data on homosexuals, and with the assumption of independent modular mechanisms, rather than any existing sociocultural models. Einon also incorrectly assumes that evolutionary models have overemphasized male choice to the exclusion of female choice.

Embodiment, the explicit dependence of cognition on the properties of the human body, is the foundation of contemporary cognitive science. Ballard et al.'s target article makes an important contribution to the embodiment story by suggesting how limitations on neural binding ability lead to deictic strategies for many tasks. It also exploits the powerful experimental method of instrumented virtual reality. This commentary suggests some ways in which the target article might be misinterpreted and offers other cautions.

Although it provides a useful description of elementary movement trajectories, we argue that the delta-lognormal model is deficient as an account of speed/accuracy tradeoffs in aimed movements. It fails in this regard because (1) it is deterministic, (2) its formulation ignores critical task elements, and (3) it fails to account for the corrective role of submovements.