Piaget stimulated a generation of research by postulating qualitative shifts in the developmental abilities of human organisms. Courage and Howe (2002) refer to this view as epigenetic constructivism, or the belief that infants are born without domain specific knowledge, but acquire such knowledge as a function of domain general processes. They define domain specific knowledge as “specific to a single cognitive domain under the control of more specific brain-mind functions.” They further define domain general abilities as “cognitive abilities that influence performance across a wide range of situations or domains” (pp. 251-252). Examples of domain general functions might include processing speed and memory capacity. An example of a domain specific process might be facial recognition.
To Piagetians, domain specific knowledge grows out of numerous interactions between the organism’s biologically based domain general abilities (such as assimilation and accommodation), and the environmental context. Underscoring these tenets is the postulation that organisms develop in a discontinuous rather than continuous fashion. Discontinuous development refers to the theory that development occurs in relatively abrupt changes of domain general function over a brief time span, that leads to different, more long-term functional patterns. Continuous development refers to the notion that domain general processes evolve slowly over time and are more domain specific. The following essay will address this specificity/generality issue, and quantitative/qualitative issue in terms of the development of individual differences. First the discussion will focus on some philosophical/definitional issues, and then explore emerging support for the continuity paradigm across social-cognitive, general developmental, and personality fields. Finally, future directions will be discussed.
Before reviewing some of the evidences across the developmental track for the continuity paradigm, brief discussion about semantics and level of analysis is warranted. Courage and Howe (2002) discuss problematic definitions and methodology in their opening statements, citing these areas as sometimes ambiguous or misleading. For example, when speaking of a qualitative shift, it may be important to define both the meaning of the word “shift” as well as the unit of analysis being observed in the “shift.” A qualitative shift in type of behavior may be very different from a qualitative shift in behavior itself. For illustration, suppose I code verbal output in an Autistic child from the 1st-4th year of life. Findings indicate that the participant increased her vocabulary minimally from 1½-2½ years, and dramatically from 2½-4 years. What have I really evidenced? All that my data show is a qualitative shift in verbal behavior (or domain specific function). To evidence a shift in type would require a different level of analysis than to simply graph word acquisition and production.
Suppose that I had incorporated coding techniques that allowed me to analyze not only absolute frequency of word production, but also syntax and semantics. My findings reveal that from 2½-3½ years the youngster was simply engaging in echolalia (or simple verbal reproduction without communicative intent or meaning), but from 3½-4 years the youngster began to use words appropriately with communicative intent. Now I have evidenced a qualitative shift in type of behavior.
Finally, suppose that I had also administered periodic fMRI scans during the research project, and found that during the 3½-4 year period of the experiment, when the Autistic participant began using language appropriate skills to communicate, the fMRI is notable for a right to left hemisphere dominant shift in activity. I have now evidenced a qualitative shift in type of behavior and underlying neural function (i.e., domain general qualitative shift).
The point is that Courage and Howe (2002) criticize much of the past research for ignoring such important semantic differences, and for poor methodology that analyzes at an inappropriate unit of analyses. With the prior discussion in mind, we are now ready to explore some of the evidences relating to the continuity/discontinuity debate across the fields of social cognition, cognition, and personological functioning.
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