Authors frequently refer to gene-based selection in biological evolution, the reaction of the immune system to antigens, and operant learning as exemplifying selection processes in the same sense of this term. However, as obvious as this claim may seem on the surface, setting out an account of “selection” that is general enough to incorporate all three of these processes without becoming so general as to be vacuous is far from easy. In this target article, we set out such a general (...) account of selection to see how well it accommodates these very different sorts of selection. The three fundamental elements of this account are replication, variation, and environmental interaction. For selection to occur, these three processes must be related in a very specific way. In particular, replication must alternate with environmental interaction so that any changes that occur in replication are passed on differentially because of environmental interaction. One of the main differences among the three sorts of selection that we investigate concerns the role of organisms. In traditional biological evolution, organisms play a central role with respect to environmental interaction. Although environmental interaction can occur at other levels of the organizational hierarchy, organisms are the primary focus of environmental interaction. In the functioning of the immune system, organisms function as containers. The interactions that result in selection of antibodies during a lifetime are between entities (antibodies and antigens) contained within the organism. Resulting changes in the immune system of one organism are not passed on to later organisms. Nor are changes in operant behavior resulting from behavioral selection passed on to later organisms. But operant behavior is not contained in the organism because most of the interactions that lead to differential replication include parts of the world outside the organism. Changes in the organism's nervous system are the effects of those interactions. The role of genes also varies in these three systems. Biological evolution is gene-based (i.e., genes are the primary replicators). Genes play very different roles in operant behavior and the immune system. However, in all three systems, iteration is central. All three selection processes are also incredibly wasteful and inefficient. They can generate complexity and novelty primarily because they are so wasteful and inefficient. Key Words: evolution; immunology; interaction; operant behavior; operant learning; replication; selection; variation. (shrink)

For a long time, several natural phenomena have been considered unproblematically selection processes in the same sense of “selection.” In our target article we dealt with three of these phenomena: gene-based selection in biological evolution, the reaction of the immune system to antigens, and operant learning. We characterize selection in terms of three processes (variation, replication, and environmental interaction) resulting in the evolution of lineages via differential replication. Our commentators were largely supportive with respect to variation and environmental interaction but (...) critical with respect to replication, in particular its appeal to information. With some reservations, our commentators think that our general analysis of selection may fit gene-based selection in biological evolution and the reaction of the immune system but not operant learning. If nothing else, this article shows that the notion of selection is not as straightforward as it may seem. (shrink)

The case for the value of self-experimentation in advancing science is convincing. Important features of the method include (1) repeated measures of individual behavior, over extended time, to discover cause/effect relations, and (2) vivid graphical presentations. Large-scale research on Pavlovian conditioning and weight control is needed because verification could result in easy and inexpensive mitigation of a serious public health problem.

If selection is interpreted as involving repeated cycles of replication, variation, and environmental interaction so structured that environmental interaction causes replication to be differential, then selection in gene-based biological evolution and the reaction of the immune system to antigens are relatively unproblematic examples of selection processes. Operant learning and cultural evolution pose more serious problems. In this response we deal with operant learning as a selection process. Footnotes1 The authors regretfully inform readers that since the publication of our target article (...) in 2001, one of our coauthors, Rod Langman, has died. (shrink)