major contributions emanating from sagvolden et al.'s theory include elucidation of the role in attention-deficit/hyperactivity disorder (adhd) of temporal information processing, social learning, and response extinction learning. key issues include a need for clearer explanation of the relative role of impulsivity versus response suppression/inhibition in the dual process model, and delineation of genotype-environment correlations versus interactions in the social and experiential mechanisms posited.

“A dynamic developmental theory of attention-deficit/hyperactivity disorder (ADHD) predominantly hyperactive/impulsive and combined subtypes” is a major contribution linking comparative psychology with clinical developmental neuropsychopathology. In this commentary, I place some critical remarks concerning the theory’s explanation of sleep problems, inhibition, error monitoring, and motor control.

derived from a rat model, the theory of sagvolden et al. offers an all-explanatory model of attention-deficit/hyperactivity disorder (adhd) anatomy, behaviour, and cognition as being caused predominantly by a hypo-dopaminergic mesolimbic (affecting the mesocortical and nigrostriatal) system, leading to abnormal reward and extinction processes. this model suffers from oversimplification and reductionism, reflecting the limitations of the use of animal models to explain higher mental disorders.

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.

this commentary speaks to the relationship between depue & marrone-strupinsky's (d&m-s's) concept of trait affiliation and affiliative memory and the formation of human community, especially among peer groups. the target article suggests a model for how and why dynamic communities form in a number of disparate contexts and under a number of circumstances.

The dynamic developmental theory (DDT) has benefited from the insights of the commentators, particularly in terms of the implications for the proposed steepened delay gradients in attention-deficit/hyperactivity disorder (ADHD). The introduction of modified memory processes as a basis for the delay gradients improved the links to aspects of ADHD. However, it remains unclear whether the hyperactive-impulsive and inattentive subtypes are separate subgroups or may be explained as different outcomes of the same genetic factors and thus explicable by the same principles. The DDT suggests that altered reinforcement and extinction processes define an endophenotype in ADHD that can be related dimensionally to inattention, hyperactivity, and impulsivity. The relation between the suggested endophenotype, characterized by changes in basic learning mechanisms, and other endophenotypes characterized by delay aversion or response disinhibition, needs to be tested in future studies.