Notwithstanding many similarities between Thelen et al.'s and Piaget's accounts of the A-not-B error, we argue that, in contrast to Piaget, they do not explicitly address the issue of objectivity. We suggest that this omission is partly due to the fact that Thelen et al. and Piaget's accounts are pitched at different levels of explanation.

We question the falsifiability of Tsuda's theory and emphasise the need for physiologically based, quantitative models of large scale cortical function that can be validated through experimental data. We outline such a model emphasising its verification through experimental data and possible avenues for testing Tsuda's predictions about nonlinearities in neural behaviour.

In agreement with the target article, we would like to point out a few aspects related to embodiment which further support the position of biorobotics. We argue that, especially when complex systems are considered, modeling through a physical implementation can provide hints to comprehend the whole picture behind the specific set of experimental data.

Methods in experimental economics are reminiscent of the methods employed by behaviorists in the first half of the twentieth century. Empirical and conceptual progress led the field of psychology away from the principles of behaviorism, and experimental economists should consider whether the criticisms leveled against behaviorists might apply equally to them.

I discuss Stoffregen & Bardy's theory from the perspective of the complementary aspect of input conflict, namely, imput coherence - the unity of perception. In a classical approach this leads to the famous “binding problem.” The conceptual framework the authors construct leaves no space for a binding problem to arise. A remaining problem of perceptual conflict, arising in cases of inversion of the visual field can be handled by the theory the authors propose.

Shepard's analysis of how shape, motion, and color are perceptually represented can be generalized. Apparent motion and shape may be associated with a group of spatial transformations, accounting for rigid and plastic motion, and perceived object color may be associated with a group of illuminant transformations, accounting for the discriminability of surface-reflectance changes and illuminant changes beyond daylight. The phenomenological and mathematical parallels between these perceptual domains may indicate common organizational rules, rather than specific ecological adaptations. [Barlow; Hecht; Kubovy & Epstein; Schwartz; Shepard; Todorovič]

Tenenbaum and Griffiths' paper attempts to subsume theories of similarity – including spatial models, featural models, and structure-mapping models – into a framework based on Bayesian generalization. But in so doing it misses significant phenomena of comparison. It would be more fruitful to examine how comparison processes suggest hypotheses than to try to derive similarity from Bayesian reasoning. [Shepard; Tenenbaum & Griffiths]

We consider the significance of high-dimensional transitory dynamics in the brain and mind. In particular, we highlight the roles of high-dimensional chaotic dynamical systems as an “adequate language” (Gelfand 1989), which should possess both explanatory and predictive power of description. We discuss the methods of description of dynamic behavior of the brain. These methods have been adopted to capture the averaged or deterministic complexity, and further to allow for discussion of a new approach to capture the complexity of the deviation from such an averaged complexity and also the complexity of interactive modes. We also give arguments in defense of our models for dynamic memory with chaotic itinerancy and Cantor coding. In addition, we discuss the reality that a model of the brain and mind should reflect.

Webb compares robots to other behavior models in a novel space, but neglects significant portions of this space. The article's analysis of models would have been strengthened by including a broader coverage of physically embodied models and of models of social behavior. Nevertheless, Webb is correct to claim that robot construction will contribute to understanding behavior.

The authors attempt to prove that single energy arrays cannot specify reality. We offer contrary evidence that motion structures the acoustic array to specify fundamental attributes of the source. Against direct detection in general, we cite evidence that humans weight acoustic inputs differentially when making perceptual judgments of auditory motion.

In this commentary, we question (1) how embodied Thelen et al.'s model is relative to their aims, and (2) how embodied the behavior of children is in particular response systems, relative to how much dynamic systems theory emphasizes this idea. We close with corrections to mischaracterizations of an alternative, neural network perspective on infant behavior.

Hertwig and Ortmann have made a laudable effort to bring together experimental practices in economics and in psychology. Unfortunately, they ignore one of the primary objectives of psychological research, which is an analytic description of general cognitive processes. Among experimental practices in probability judgment tasks they discussed, we will focus hereafter on enactment of scripts and repetition of trials.

We emphasize the feature of Webb's presentation that bears most directly on contemporary research with real animals. Many neuroscience modelers erroneously conclude that a model that performs like an animal must have achieved this goal through processes analogous with those used by the animal. A simulation failure justifies rejecting a model, but success does not justify acceptance. However, an important benefit of models, successful or otherwise, is to stimulate new research.

The authors wish that the psychology of human decision making should borrow methodological rigor from economics. However, unless economics also borrows from psychology this poses a danger of overly limiting the phenomena studied. In fact, an expanded economic theory should be sought that is based in psychology (and ultimately neuroscience) and encompasses both rational and irrational aspects of decision making.

Based on concepts of self-organization, we interpret apparent motion as the result of a so-called non-equilibrium phase transition of the perceptual system with the stimulus-onset asynchrony (SOA) acting as a control parameter. Accordingly, we predict a significantly increasing variance of the quality index of apparent motion close to critical SOAs. [Shepard]

Thelen et al. criticize “spatial coding” approaches to the A-not-B error. However, newer thinking about spatial coding provides more precise analytic categories and recognizes that different spatial coding systems normally coexist. Theorizing about spatial coding is largely compatible with dynamic-systems theory, augmenting it with an analysis of what one means when discussing “location at A” (or B).

The propositions that the senses are separate and that the global array may be sufficient for adequate perception are questioned. There is evidence that certain tasks may be primarily “input-driven,” but these are a special case along the behavioral continuum. Many tasks involve sensory information that is ambiguous, and other sources of information may be required for adequate perception.

Traditional approaches to human information processing tend to deal with perception and action planning in isolation, so that an adequate account of the perception-action interface is still missing. On the perceptual side, the dominant cognitive view largely underestimates, and thus fails to account for, the impact of action-related processes on both the processing of perceptual information and on perceptual learning. On the action side, most approaches conceive of action planning as a mere continuation of stimulus processing, thus failing to account for the goal-directedness of even the simplest reaction in an experimental task. We propose a new framework for a more adequate theoretical treatment of perception and action planning, in which perceptual contents and action plans are coded in a common representational medium by feature codes with distal reference. Perceived events (perceptions) and to-be-produced events (actions) are equally represented by integrated, task-tuned networks of feature codes – cognitive structures we call event codes. We give an overview of evidence from a wide variety of empirical domains, such as spatial stimulus-response compatibility, sensorimotor synchronization, and ideomotor action, showing that our main assumptions are well supported by the data.

That perception and action share abstract representations is a key insight into the organization of intelligence. However, organizing behavior requires additional representations and processes which are not “early” sensing or “late” motion: structures for sequencing actions and arbitrating between behavior subsystems. These systems are described as a supplement to the Theory of Event Coding (TEC).

By delineating the parametric variations that affect infant performance in the standard A-not-B search task, the Thelen et al. model provides an important contribution to the field of infant development. We discuss several broad issues pertinent to interpreting the model. We note that the phenomenon modeled by Thelen et al. is not necessarily the one originally described by Piaget. We describe data on infant self-correction that are not addressed by the Thelen et al. model. Finally, we suggest that psychological constructs such as representation and knowledge structures are valuable to our understanding of the A-not-B phenomenon in particular and psychological development in general.