Diurnal variations in suggestibility

Abstract

The size-weight illusion was used in an effort to get a measure of suggestibility. 15 subjects, 10 men and 5 women, were given the test five times daily for 26 days. The standard (large) block weighed 55 grams. From the array of smaller blocks one was, at each test, selected as equal to the standard. After 16 days the curve of error from day to day became a straight line, so it was concluded that practice had been eliminated, and comparisons were then made of diurnal changes. The average weight chosen became gradually smaller and smaller in the course of the day, decreasing by 1 gram from early morning to late afternoon. However, the changes found were considered so slight and unreliable that the results were supposed only to raise the question, not to settle the issue. (PsycInfo Database Record (c) 2025 APA, all rights reserved)