The principle of nonadditive determinism derives from the literature on integrative, multilevel analyses, which extend across levels of organization (e.g., psychological, physiological, cellular) and analysis (e.g., behavioral, neurophys-iological, molecular). The principle of nonadditive determinism specifies that properties of the whole are not always readily predictable from the properties of the parts (see Cacioppo and Berntson 1992). Some properties of crystals (e.g., table salt) cannot be predicted from the characteristics of the individual elements (sodium and chloride) in isolation. Those properties become known only when the elements are found in association or interaction with others. A behavioral example comes from the considerable individual differences that are apparent in the effects of drugs. Some individuals are more affected by, and at greater risk for addiction to, cocaine or other drugs of abuse. Similarly, studies with primates have shown that some monkeys work harder and self-administer more cocaine than others (Morgan et al. 2002). This is not mere random variation, but relates to the animal’s social status—submissive animals show higher levels of cocaine self-administration than dominant animals. This is now understood to be attributable to reciprocal interactions between social dominance, brain dopamine function, and drug reward processes. The important point is that social status, which serves as the informative and organizing construct in this literature, could not be determined in the absence of behavioral measures in a social context.
Even if the properties of, for example, Beethoven’s Ninth Symphony can be fully specified through reference to lower-level physical characteristics (i.e., time-varying frequencies), the composition’s aesthetic features may be more readily apparent or appreciated through higher-level auditory perception. This presence of higher-level aesthetic processes defines a functional quality of the acoustic signals that might otherwise escape recognition. It also serves to focus attention on the important interactions among levels of organization and analysis that may ultimately contribute to the development of a science of aesthetics.
Reciprocal determinism is a related construct. Reciprocal determinism is the mutual back-and-forth interaction among distinct levels of organization (e.g., behavioral and cellular) that requires consideration of both levels for a comprehensive understanding of either. Hormones, for example, can have notable psychological effects, but it is also the case that psychological variables can powerfully impact hormone levels. It is this reciprocal back-and-forth interaction among levels that often under lies nonadditive determinism, in which the whole can seem to be more than the sum of its parts.
Nonadditive determinism is not inconsistent with genetic determinism. Drug administration is subject to potent genetic determinants, related to dopamine functions as well as a range of other heritable characteristics, including behavioral variables that contribute to dominance status. Rather, nonadditive determinism is orthogonal to genetic determinism—that is, the two operate independently but simultaneously, emphasizing the multiple levels of organization that interact in the manifestations of genetic (as well as environmental) determinants. Genetic determinism focuses on the gene and gene products, whereas nonadditive determinism emphasizes the structural and functional architectures through which genetic and environmental factors determine outcomes and behaviors.
