Jackendoff's Foundations of Language: Brain, Meaning, Grammar, Evolution has many points of similarity with Skinner 's analysis of verbal behavior, though the former emphasizes structure whereas the latter emphasizes function. The parallels are explored in the context of a selectionist account of behavior in general and of verbal behavior in particular. Part of the argument is that behavior drives evolution and therefore also drives brain organization. Another concerns itself with the nature of explanation. Recent experimental developments in behavior analysis are (...) reviewed as potential contributions to an understanding of language that incorporates its functional as well as structural dimensions. (shrink)

Wilkins & Wakefield assign importance to motor systems but skip from anatomy to cognitive structure with little attention to behavior. Organisms, no matter how sophisticated, that do not behave in accord with what they know will fall by the evolutionary wayside. Facts about behavior can supplement the authors' theory, whose hierarchical structures can accommodate an evolutionary scenario in which a million years or more of functionally varied utterances mainly limited to single words is followed by an explosion of linguistic diversity (...) with the development in the last 50,000 years or so of syntactically organized multiple word utterances. (shrink)

This commentary argues that Evans & Levinson (E&L) should expand their two-track model to a three-track model in which biological and cultural evolution interact with the evolution of an individual's language repertories in ontogeny. It also comments on the relevance of the argument from the poverty of the stimulus and offers a caveat, based on analogous issues in biology, on the metaphor of language as a container, whether of meanings or of other content.

Evolutionary contingencies select organisms based on what they can do; brains and other evolved structures serve their behavior. Arguments that brains drive language structure get the direction wrong; with functional issues unacknowledged, interactions between central structures and periphery are overlooked. Evidence supports a peripherally driven central organization. If language modules develop like other brain compartments, then environmental consistencies can engender both structural and functional language units (e.g., the different phonemic, semantic, and grammatical structures of different languages).

Hull et al. rightly point out the special character of selection as a causal mode, but ironically they seem to force selection back into traditional causal modes by decomposing it into replication, variation, and environmental interaction. Many processes are selective, and a taxonomy of a broad range of kinds of selection may be preferable to narrowing the applicability of the term.

Sagvolden, Johansen, Aase, and Russell (Sagvolden et al.) examine attention-deficit/hyperactivity disorder (ADHD) at levels of analysis ranging from neurotransmitters to behavior. At the behavioral level they attribute aspects of ADHD to anomalies of delay-of-reinforcement gradients. With a normal gradient, responses followed after a long delay by a reinforcer may share in the effects of that reinforcer; with a diminished or steepened gradient they may fail to do so. Steepened gradients differentially select rapidly emitted responses (hyperactivity), and they limit the effectiveness (...) with which extended stimuli become conditioned reinforcers, so that observing behavior is less well maintained (attention deficit). Impulsiveness also follows from steepened gradients, which increase the effectiveness of smaller, more immediate consequences relative to larger, more delayed ones. Individuals who vary in the degree to which their delay gradients are steepened will show different balances between hyperactivity and attention deficit. Given the range of ADHD phenomena addressed, it may be unnecessary to appeal to additional behavioral processes such as extinction deficit. Extinction deficit is more likely a derivative of attention deficit, in that failure to attend to stimuli differentially correlated with extinction should slow its progress. The account suggests how relatively small differences in delay gradients early in development might engender behavioral interactions leading to very large differences later on. The steepened gradients presumably originate in properties of neurotransmitter function, but behavioral interventions that use consistently short delays of reinforcement to build higher-order behavioral units as a scaffolding to support complex cognitive and social skills may nonetheless be feasible. Key Words: ADHD; attention deficit; delay gradient; exponential decay; extinction deficit; hyperactivity; impulsiveness; intervention; observing responses; self-control. Footnotes1000 Jeffrey Gray was the BBS Editor for this treatment. When he accepted Sagvolden et al. for publication, he invited Catania, who was one of the reviewers of the original submission, to prepare a precommentary. Com-mentators were then invited to respond to the Sagvolden et al. article, to the Catania precommentary, or to both. (shrink)

Some commentaries suggest that the attention-deficit/hyperactivity disorder (ADHD) theory of this condition does not explain enough. Because the theory includes parameters of the delay gradient that vary across individuals and developmental modulation of behavioral outcomes by different environments, it accommodates a wide range of manifestations of ADHD symptoms. Thus, the argument could instead be made that the theory allows too many degrees of freedom. For many purposes, behavior is better defined in terms of function (e.g., consequences) than in terms of (...) structure (e.g., muscle movements), so cognition is treated here as a variety of behavior rather than as a different category of phenomena. The commentaries are discussed in the context of these and other distinctions, including those between association and selection, between operant and respondent behavior, and between fundamental processes and those that are derivative. Other issues include: prosthetic environments, rapidity of developmental change, the concept of inhibition, the form of the delay gradient, and possible directions for experimental research. (shrink)

Fifty years or so after the cognitive revolution, some cognitive accounts seem to be converging on treatments of how we come to know about ourselves and others that have much in common with behavior analytic accounts. Among the factors that keep the accounts separate is that behavioral accounts take a much broader view of what counts as behavior.

Metaphors and models involve correspondences between events in separate domains. They differ in the form and precision of how the correspondences are expressed. Examples include correspondences between phylogenic and ontogenic selection, and wave and particle metaphors of the mathematics of quantum physics. An implication is that the target article's metaphors of resistance to change may have heuristic advantages over those of momentum.