EVOLUTION OF INSTINCTS

New Zealand Herald, Volume LXIX, Issue 21278, 3 September 1932, Page 7 (Supplement)

EVOLUTION OF INSTINCTS

EXPERIMENTS WITH RATS The zoology section and the education, psychology, and philosophy section of the recent Science Congress in Sydney had a joint discussion on the evolution of instincts. Professor Agar said that the only known characteristic of animals on which the acquired habit theory of instinct could base itself was their tendency to repeat actions which they had accidentally found to givo satisfaction, and to avoid actions which they had accidentally found to give dissatisfaction. Professor Tasman Lovell contended that instincts 1 originated gradually with the growth of the organism; that the gradual growth of instinct was by progressive transmission by parents to offspring of acquisitions they themselves had made; and that the experiences of the parent, which were capable of impressing themselves deeply enough'for heredity transmission, were total experiences of the organism, and not local experiences of a part. If there was no warrant for accepting the Lamarckian hypothesis, then the nature of tho evolutionary process in the plan of mind in the scheme of nature remained utterly unintelligible. Professor Lovell explained experiments conducted with tank and control rats. Hats were given the opportunity of escaping along a lighted passage or a dim passage. If they chose the former they received a slight electric shock at the end. On the first day of training 62 tank rats chose the dim gangway and 76 tho bright gangway; while 99 control rats chose the former and 335 the latter. After 30 days of training 115 tank rats chose tho dim gangway, and only 23 the bright, and 126 control rats selected the dim, and 108 the bright • gangways. Tests with rats of successive generations, in which no electric shocks were administered, revealed that while control rats showed a slight preference for the bright gangway, the tank rats showed a decided preference for the dim. These results, he claimed, supported the Lamarckian hypothesis.

In the discussion which followed it was generally agreed that experiments with rats should bo checked before being criticised. ,

SEVERE CLIMATE OF VENUS If there are inhabitants on Venus, Professor Philip Fox, of the Alder Planetarium, says that they aro " tough customers." " Talk about life on Venus is puro speculation," ho said recently, " But from what wo know of its climate, ils inhabitants, if any, are indeed tough." A day on Venus is 20 earth days long. The night is the same. Getting accustomed to a warm rlav and then being subjected to a chilly 20-day night, tho professor believes, would make tho supposed dwellers of the planet hardy enough for almost anything. Speculation about the possibility of inhabitants on Venus was recently begun anew when astronomers discovered that there is present on Venus largo quantities of carbon dioxide, indicative of existence in some form.

SHIP'S SIXTH SENSE Not oven a rowing boat can hide in the fog from a new safety device which will guard ships from collision at sea. Ihe device emits an eerie, high-pitched whistle, which re-echoes so distinctly to tho sending boat that its pilot is said to bo able to locate perils iu any direction from one-sixth to half a mile away. It is claimed that the device has located in fog a small rowing-boat with two occupants 800 ft.. away. A sailing boat was spotted at 1350 ft., a 538-ton steamship was located in thick fog at distances of 1360 ft. to 2160 ft. The apparatus consists of three large megaphones. One sounds the automatic whistle; the other two aro the receiving' echo " ears." Sounds from either side reach one " car" a tiny fraction ahead of tho other. Sounds dead ahead or astern arrive simultaneous!}'. COMPRESSED AIR ENGINE Three men in San Antonio, Texas, after three years of work, havo just completed a 5501b. locomotive model which cost about £2600, and is operated by compressed air instead of steam. With its tender, the engine is nine feet long and contains more than 40.000 parts. The designers claim that the power piinciple of compressed air supplied by motors is also adaptable to full-size engines. They are now building box cars other equipment to complete a train which the locomotive will haul.