Third Report on a Lamarckian Experiment

Abstract

I. Introductory (pp. 213-218). 11. The continuation of the tank experiment to the 341h gejieration (pp. 218-221). 111. The behaviour in the tank of control rats of various stocks (pp. 221-224). IV. The continuation of the experiinetzt cor)tbining training i n the tank with V. An experiment cotnbining training i n the tank with favourable selection adverse selection (pp. 224-231). (pp. 231-232). VI. Brief answer to soine criticism (pp. 232-23.5). * (1927) XVII, 267 and (1930) xx, 201. J. of Psych. XXIV. 2 14 214Third Report on a Lamarckian Experiment escaping from a tank of water, and to prefer always the only alternative route of escape, namely, a similar gangway dimly lit and not electrified. Pig. 1 represents the ground plan of the tank; A and B are the two sloping gangways.Both are of ground-glass covered with wire-mesh and behind each is an electric glow-lamp of 60 candle-power. The tank is half-full of water and each gangway leads up to the platform P from a level just above the surface of the water. The wire-mesh on the gangway is insulated from the metal walls of the tank and from the water, but is connected with one pole of a secondary coil, the other pole of which is connected with the metal tank and thus with the water. If a rat, swimming in the water, places his fore paws on the wire-mesh of the gangway (while this is receiving the interrupted current from the coil) he bridges the electric gap, and the interrupted current, entering his fore paws, passes through his body to the water, and continues to do so, as he runs up the gangway, until his tail is clear of the water. The strength of the current which passes through the rat (and the intensity of the impression made on it, as judged from its behaviour) inevitably varies a little in ways which cannot be completely controlled (e.g. the kind of contact made with the wire by the rat's feet). After much consideration of this problem of standardizing the shock delivered to the rat, I am of the opinion that the best one can do is to adjust the secondary coil in such a way that the current is strong enough to tetanize the muscles of the rat's legs and hold him fast, in, as nearly as possible, 50 per cent. of all contacts made by any batch of rats. Further, when a rat is thus held by the current, I count three slowly before breaking the current and releasing the rat. I n almost all cases the rat then runs up the gangway. When a rat touches the wire-mesh with paw or snout, it happens in rare instances that he turns back; but with these rare exceptions he (if not tetanized) rushes as quickly as possible up the gangway.

Fourth Report on a Lamarckian Experiment

“…The criticisms made by Dr T. M. Sonneborn (10) have in the main been answered in the foregoing paragraphs of this report and in my Third Report (2). They concern chiefly (1) tbe possibility of unwitting favourable selection, which, I think, is sufficiently answered by my W.H.…”

The Hebb Synapse Before Hebb: Theories of Synaptic Function in Learning and Memory Before Hebb (1949), With a Discussion of the Long-Lost Synaptic Theory of William McDougall

“…However, he was not well received in the United States. As he himself noted, he was prone to champion ideas that were rejected by the mainstream in psychology and physiology and at Harvard he was a vocal critic of behaviorism, proposed that human behavior was based on a catalog of instincts, supported eugenics and set forth on a long series of experiments using white rats to study Lamarckian inheritance ( McDougall, 1927 , 1930 ; Rhine and McDougall, 1933 ). He came to believe that the main problem with psychology was the acceptance of mechanistic biology, and the neglect of the purposive or teleological aspect of mental life.…”

Inheritance of acquired characters in animals: A historical overview, further evidence and mechanistic explanations

“…It is worth noting that Mcdougall attained world-wide fame as a brilliant experimental psychologist. He repeatedly showed that when rats were forced by unpleasant experience to acquire a habit, they produced offspring which acquired the habit more readily than did their parents until, at the end of nine years; they acquired the habit at the first contact with the unpleasant experience (Rhine & Mcdougall 1933;Mcdougall 1938). Lindqvist et al (2007) showed that the offspring of chickens raised in stressful conditions have an affected phenotype and brain gene expression, which mirrors that of their parents, supporting previous observations that have shown that offspring phenotypes may be affected by parental experiences preceding pregnancy, and even persist over more than one generation.…”