The unification of psychology is an important goal, and Posner and Rothbart (this issue) do psychology a great service in proposing Hebb's (1949) model as a basis for unification. But Hebb's model deals only with a biological level of analysis. A more comprehensive plan for unification would deal with ecological and cultural levels of analysis as well. In this article, I propose a more encompassing basis for thinking about unification, and give an example of how taking into account cultural context may change one's perspective on psychological phenomena.
Clichés are often boring. Sometimes, however, they are true. One such cliché is "United we stand. Divided we fall." The slogan has been traced to various sources. For one thing, it is the motto of the Commonwealth of Kentucky in the United States (http://www.phrases. org.uk/bulletin_board/8/messages/1009.html). But it goes further back to the Liberty Song, composed by John Dickinson in 1768 (http://www.phrases.org.uk/ btilletin_board/8/ messages/1013.html). Going even further back to Biblical times, Jesus said, "If a house be divided against itself, that house cannot stand" (Mark 3:25) (http://www. btinternet.com/~sj.mackay/foundations/smuni ted. ht ml).
Clearly, the view of Posner and Rothbart (this issue) that psychology will do better united than divided has deep historical roots, as described above, as well as some more recent historical ones (e.g., Staats, 1999; Sternberg, 2002, 2003; Sternberg & Grigorenko, 200Ia). Posner and Rothbart are particularly interested in Hebb (1949, 1958) as bases for exploring the unity of psychology, and in particular, Hebb's theory of the organization of behaviour through what are now called neural networks. Posner and Rothbart's wonderful article shows how Hebb's theory can provide a basis for thinking about psychological science in a unified way.
I strongly support and applaud Posner and Rothbart's efforts to unify psychology. I differ from them only in means, not in goals. In terms of means, I view the biological level of analysis as an important one for the unification of psychology. But I see the study of biological bases and correlates of behaviour as a start, rather than as a finish toward this unification. Thus, I differ somewhat from Posner and Rothbart in how I think unification should be achieved.
First, I believe unification cannot be reductionistic, based only on a single level of analysis. Rather, it should recognize that environmental contexts as well as biology play a crucial role in behaviour and in unifying psychology.
second, I prefer as a goal the unification of psychology rather than psychological science. My own goal is to bring together not only scientists of different stripes, but also those who might view themselves as interested in psychology, but not necessarily primarily in psychology as a science. For example, therapists might view their primary allegiance to the practice rather than the science of psychology. Well more than half the professionals who are, one way or another, in the business of psychology, are concerned primarily with applications of psychological science, rather than with psychological science, per se. I believe it important to include them in the mission of unification because it is so easy for science and practice to become separated and even antagonistic (Sternberg, 2003).
A Framework for Unification
A framework for unification needs to take into account both biological and contextual levels of analysis. A start for thinking about unification is culture. Culture can be defined as "the set of attitudes, values, beliefs and behaviours shared by a group of people, communicated from one generation to the next via language or some other means of communication" (Barnouw, as cited in Matsumoto, 1994, p. 4). Cultural context does not necessarily form a single context. For example, Berry and Irvine (1986) have proposed four nested levels of cultural context. …