50 years ago

Current theory tends to emphasize the importance of interference in forgetting and to minimize the role of time lapse in the decay of the memory trace. Conrad, however, has recently shown that the immediate recall of eight-digit numbers is better when the numbers are presented and reproduced by subjects at a fast rate than when they are presented and reproduced at a slow rate ... I tested two groups of subjects for their ability to retain eight-digit numbers when presented and reproduced at different rates. Group A consisted of 26 teachers, aged 18–29, drawn from different regions of Canada. Group B consisted of 26 teachers, aged 30–55 ... [T]here is no significant difference between the two groups in the proportion of digits recalled at the fast rate, but there is a significant difference between the two groups (P = 0.05) in the proportion of digits recalled at the slower rate ... [I]t appears that the span of immediate memory is the same for the two age groups, but that the rate of decay of immediate memory tends to increase with age.

From Nature 25 October 1958.

100 years ago

Dr. F. A. Dixey pointed out that when Fritz Müller put forward, in 1879, his theory of common warning colours, or the assimilation of one distasteful form to another for the sake of mutual protection against insectivorous enemies, he recognised the probability, or even certainty, that the approach would not necessarily be one-sided, but might be convergent, each form in some respects advancing to meet the other. This suggestion, however, was never developed by Fritz Müller ... Dr. Dixey showed that there is much evidence that such reciprocal approach, or interchange of obvious characters ... does actually occur, and he exhibited some cases of mimicry the peculiar features of which are difficult to explain on any other hypothesis.

From Nature 22 October 1908.