Heredity of Acquired Characters

views updated

HEREDITY OF ACQUIRED CHARACTERS

The expression "heredity of acquired characters" generally refers to the transmission to descendants of modifications taking place in the course of the individual life of a forebear, such transmission being possible by virtue of these modifications being integrated into the forebear's genotype. Such modifications may be morphological, functional, or even behavioral (acquired through learning). This idea, which was central to the evolutionism of Jean-Baptiste Lamarck, was later very largely rejected. Freud nevertheless accorded it a non-negligible role in some of his theoretical views.

We have to bear in mind that psychiatry and psychology at the end of the nineteenth century were very strongly marked by the idea that individual characteristics were essentially determined by hereditary data (in the genetic sense), whether in reference to normal or pathological development, including mental pathologies. It must also be said that in this domain the theory of degeneration was well established.

It is not surprising that Freud initially stood by the theory. In 1888 he wrote, in agreement with Jean Martin Charcot, that "the aetiology of the status hystericus is to be entirely looked for in the heredity" (1888b). However, he made a clear distinction over the following years between the inherited "constitutional" causes that provide the individual's base psychic terrain, and the "occasional causes," principally the vicissitudes of sexual life, which alone could explain the appearance and form of the mental pathology. Publishing his translation of Charcot's Leçons du mardi (Tuesday lectures), he went so far as to contradict him by writing that "the most frequent cause of agoraphobia, as well as the other phobias, does not reside in heredity but in the anomalies of sexual life" (1892-94a).

In Studies on Hysteria (1895d) he actively criticized recourse to the notion of degeneration as an explanation of hysterical phenomena, and restated the complementary nature of constitutional and accidental causes. He never departed from this position, which he stated clearly in the manuscripts he addressed to Wilhelm Fleiss (Ms B, 1950a), then repeated in his article in French on Heredity and the Aetiology of the Neuroses (1896a), and each time over the following years that he discussed the problem of the "choice of neurosis"—the determination of a subject's evolution toward hysteria or phobia.

The problem took on a greater dimension when Freud undertook to answer the question that cannot fail to rise in such a perspective: where do the "constitutional causes" themselves come from? He answered with a thesis inspired by Charles Darwin, and even more so by Ernst Haeckel, that found its most complete formulation in Totem and Taboo (1912-13a): major events in the prehistory of humanity mark all its later development and fashion the individual development of each child. This recourse to "phylogenesis" was coupled with two postulates: the first borrowed from Lamarck (transmission of acquired characters), the second from Haeckel (ontogenesis recapitulates phylogenesis). He focused on the hereditary transmission of general developmental factors and psychic function, remaining more discreet on the subject of differential factors.

These Freudian theses have been vigorously criticized, particularly their Lamarckian aspect which seems to have been eliminated by the victory of neo-Darwinism and modern genetics. Contemporary work in molecular genetics and population genetics seems to suggest new ways of formulating the question of psychic heredity (Chiland C., Roubertoux P., 1975-1976).

Roger Perron

See also: Constitution; Cultural transmission; Identification fantasies; Instinct; Intergenerational; Phylogenesis;Phylogenetic Fantasy, A: Overview of the Transference Neuroses ; Prehistory; Thalassa. A Theory of Genitality .