Appraising the Human Developmental Sciences: Essays in Honor of Merrill-Palmer Quarterly

2. The Limitations of Concepts in Developmental Psychology

2 The Limitations of Concepts in Developmental Psychology Jerome Kagan 30 Developmental psychology, like other domains in the social sciences , is being restrained by its history. One limitation is a derivative of its philosophical parents, for the first psychologists tried to gather laboratory evidence that would prove the validity of the abstract concepts of consciousness, perception, morality, and memory. The second pull to the past comes from an awe of physics, because in psychology’s early years biology had not yet attained its currently high status. Unfortunately, both philosophers and physicists like abstract concepts that invite a commitment to Platonic essences. Philosophers , for example, continue to write about consciousness or morality as if these words named unitary natural phenomena. Physicists describe an atom of oxygen as if its features were identical in all instantiations , even though its features in air are not identical to its features when it is part of a molecule of sulfuric acid. Psychology must free itself from both traditions and recognize, as biologists do, that the functions of every hypothetical structure vary with the agent and the context of measurement. The message in this brief essay is that each experimental procedure or method of analysis influences the conceptualization of the phenomena each produces. Most scientists belong to one of two distinct groups. One cohort begins its empirical work by assuming the validity—some may prefer the word reality—of a particular concept, be it fear, intelligence , or depression, and tries to find a procedure that will index the event or processes that the concept implies. For example, neuroscientists and psychologists who are convinced that the term fear names a natural phenomenon use conditioned freezing, potentiated startle, increased salivary cortisol, or, in humans, self-reports of fear as valid reflections of the same state. The commitment to the unitary concept is so strong that advocates resist rejecting its utility, despite The Limitations of Concepts in Developmental Psychology 31 inconsistent evidence, and instead look for new methods to reaffirm their faith in the idea. The second group, more loyal to Ernst Mach and Niels Bohr than to Albert Einstein and Werner Heisenberg, reject all concepts that assume Platonic essences. These scholars believe that all nature ever reveals are robust relations between observed phenomena and that we invent words, understood to be conventions, to explain the covariation. When these scientists acknowledge the reliable relation in animals between the presence of a tone that signals electric shock and the display of body immobility (freezing), they attempt to explain the reasons for the relation. Because freezing can be induced without conditioning, and is muted if the electric shock used in conditioning is very intense, they resist ascribing a unitary state of fear to any animal. Scientific domains cycle over time in their friendliness to one or the other of these attitudes toward the relation between words and events. Because 19th-century scientists had become addicted to a priori concepts like élan vital, will, vis nervosa, and the ether, early 20th-century scholars, recognizing that the academy had filled with verbal rubbish, tried to cleanse the halls with the rules that became known as logical positivism. Percy Bridgman, Ludwig Wittgenstein, Rudolph Carnap, and Morris Schlitz led the housecleaning. But because the austerity of the positivistic rules shackled the creative intuitions that are necessary for theoretical advance, these imperatives lost their hold on the next generation, and by the 1960s words naming essences once again began to accumulate in technical journals. It is time for another housecleaning. Contemporary psychologists are addicted to assigning abstract psychological properties to animals and humans that fail to specify the agent and the context in which the properties are actualized. Obvious examples are concepts like extroversion, fear, intelligence, or secure attachment, for which the situations in which the trait is displayed are unspecified. Fewer biologists are guilty of this error because they understand that every life process is linked to a particular class of organism and actualized under particular conditions. Each person possesses representations of the events encountered most frequently in a particular context, whether forest, office, airport , stadium, television screen, or laboratory scanner. Men holding machine guns are discrepant in most settings but not on television screens. Because humans evaluate every event with respect to the situation in which it normally occurs, every event must be conceptualized as an “event in a context.” The context, like a channel setting on Jerome Kagan 32 a television...