The Temperamental Thread: How Genes, Culture, Time and Luck make Us Who We Are by Jerome Kagan

The result of a whole life’s work, Kagan’s book is an outstanding screening of the multiple and heterogeneous influences that lies beyond the facade of every human being.
Contrary to the author’s own early and admittedly wrong judgment, biological traits peculiar to each individual do have a fundamental role in defining who we are, as important as genetic inheritance and life experiences. Such undeniable biological substrate plays the background for the private happenings of life. It sets the stage, and the limits. Kagan is never bored to repeat that temperament do not tell what is possible for a person, but rather what is most unlikely to be the case. Then, environment, class identification, history, beliefs and experiences are all involved in sculpting the uniqueness of each person (which goes along with Kierkegaard’s remark about the universality of each human because of such unrepeatable combinations of cooperating factors).
Kagan proposes some rough classifications of temperamental classes, particularly for children (e.g., high- and low-reactive), but more interestingly makes clear that all definitions are transient and need to be investigated a lot more in the future, which is a grand admission for such an expert of the field. He reports the results of a large quantity of long-term studies on attitudes of people differentiated by culture, social class, ethnicity, geolocalization and more parameters, with the overarching purpose of showing, above all, how much variation is actually existing and the extent to which patterns can still be found in such variety. The identification of such patterns is, on one hand, in its infancy, on the other has a lot to say on the possibility at all, even in the face of such multilayered construction which is a man, of predicting traits, tendencies and responses from generic classes of properties (an instance is the purported association of psychological traits with physical, apparently unrelated ones). A main trend shown by Kagan with the example of many colleagues, too, is for sure the search for clear neuronal correlates between behaviors and brain states. With this respect, the final remarks on the need of a new vocabulary for neurology that shall be rather distinguished and awash from psychological fuzzy meanings and apparent though misleading inheritances are of remarkable importance. Besides, Kagan’s delicate but definite and precise dismissal of Freud’s system as son of his time and place within only a few pages is as intellectually enthralling and understanding as it can get.
For those like me interested in behavioral patterns, Kagan’s book is a must read. And it comes wrapped within the erudite, gentle, rich, pleasant, moderate yet accurate writing style which by itself tells a great deal about the author’s mastery of the field – and particularly of its issues, gaps, limits and significance.
A great piece of gentle decostructivism which, while digging a fair bit beyond apparent correlates proved wrong, and viceversa, and unveiling the supported existence of surprising patterns against the pale resistance of those who would prefer that such things could be unknowable – still leaves the reader more amazed than at the beginning of the dissection.