Contemporary psychological research is too flawed in its premises and procedures to really prove what it says it proves. So it may provide an errant basis for diagnoses and treatments, or the grand explanations of human thought and behavior derived from it, perhaps as expressed in such books as Daniel Kahneman's Thinking Fast and Slow (previously reviewed in this space).
Such a critique comes from a psychologist so eminent (and so old) that the castigation it invites from the operationally arrogant psychological establishment won't hurt him. Since it's by Jerome Kagan, Harvard professor of psychology emeritus and a distinguished author, it might even be considered. Though I don't think even he is counting on it.
Kagan isolates four problems, which come down to overconfidence in a fatally limited set of assumptions. He notes for example that psychologists often ignore differences in their human subjects, such as age, cultural background and class, as well as the setting. "Too many papers assume that a result found with 40 white undergraduates at a Midwestern university responding to instructions appearing on a computer screen in a small, windowless room would be affirmed if participants were 50-year-old South Africans administered the same procedure by a neighbor in a larger room in a familiar church in Capetown."
This is not drollery: American university students of European background were the main subjects for more than two-thirds of the papers published in six leading journals between 2003 and 2007. There are usually a small number of participants, yet universal conclusions are offered.
"Missing Contexts" is one such problem. Another is assuming everyone shares your definitions. Kagan finds that psychologists assumed that "happiness" always means the kind of self-aggrandizement that appeals to Americans. "Not one of the seven greatest pleasures listed by one American writer ... referred to acts that helped another." Yet other cultures "celebrate states of serenity, the quality and obligations linked to personal relationships, and social harmony." Another problem is inferring too much from a single measurement instead of a pattern.
Psychologists too often ignore social class in assessing "symptoms," and can be too quick to classify a trait or behavior as an illness, regardless of origin or personal difference. This is more dangerous now that drugs with serious side effects are so quickly prescribed, and all but forced on some children whose high spirits become hyperactivity, whose sadness is defined as depression, and whose shyness becomes social phobia.
Kagan is thorough and precise in this remarkable book. He has a chapter of positive recommendations, but as he notes, he's not the first to point out these limitations, which have so far mostly been ignored. What he's basically calling for is some humility, and acknowledgement of complexity, differences and connections.