McShea Lab
Current Research: Hierarchy Theory & Emotion
How do wholes affect their parts? In biology, how do large-scale processes within a multicellular organism act to control the smaller-scale processes within its component cells. Or at a higher level, how do large-scale processes within a colony control the smaller-scale behaviors of its component individuals? These are questions about hierarchical causation, and they have been central in the work of certain systems theorists, especially Herbert Spencer, Herbert Simon, Donald Campbell, Stan Salthe, and Bill Wimsatt.
My focus is the emotions in mammals (and perhaps other animals), and here the analogous question is how the emotions -- understood as higher-level structures -- control conscious thought and behavior, understood as lower-level structures? ...more...
Past Research: Complexity & Trends
Biology's First Law. In a recent book (Biology’s First Law, 2010) with philosopher Robert Brandon, we argue that complexity change in evolution is partly governed by what we call the Zero-Force Evolutionary Law (ZFEL).
The law says that in the absence of selection and constraint, complexity – in the sense of differentiation among parts – will tend to increase. Further, we argue, even when forces and constraints are present, a tendency for complexity to increase is always present. The rationale is simply that in the absence of selection or constraint, the parts of an organism will tend spontaneously to accumulate variation, and therefore to become more different from each other. Thus, for example, in a multicellular organism, in the absence of selection and constraint, the degree of differentiation among cells should increase, leading eventually to an increase in the number of cell types. As we argue in the book, the law applies at all hierarchical levels (molecules, organelles, cells, etc.). It also applies above the level of the organism, to differences among individuals in populations, and to differences among species and among higher taxa. In other words, the ZFEL says that diversity also tends spontaneously to increase. The ZFEL is universal, applying to all evolutionary lineages, at all times, in all places, everywhere life occurs. A consequence is that any complete evolutionary explanation for change in complexity or diversity will necessarily include the ZFEL as one component.
Large-Scale Trends. My past work has been mainly on large-scale evolutionary trends, that is, trends that include a number of higher taxa and that span a large portion of the history of life. Features that have been said to show such trends include complexity, size, fitness, and others. In my research, I worked mainly on developing operational measures of these features, devising methods for testing empirically whether trends have occurred, and studying the causes and correlates of trends. Most of this work so far has been on trends in complexity.
Other interests include: 1) The connections among the various evolutionary forces acting on animal form -- functional, formal, and phylogenetic. 2) Animal psychology generally. 3) The relationship between morality and human nature. And 4) the philosophy of biology generally. See a recent textbook, coauthored with philosopher Alex Rosenberg: Philosophy Of Biology: A Contemporary Introduction.
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