The Lothian Birth Cohort 1936 sample is in a uniquely good position to provide relevant data on social class mobility patterns over most of the last century. These participants, with known ultimate social class attainment, took a validated mental test in the Scottish Mental Survey of 1947 and were followed up at approximately age 70. Then, besides…

This study investigated the possibility that apparent sex differences in IQ are at least partly created by the degree of sample restriction from the baseline population. We used a nationally representative sample, the 1970 British Cohort Study. Sample sizes varied from 6518 to 11,389 between data-collection sweeps. Principal components analysis of…

Individual differences in confidence judgments made by subjects on the accuracy of their answers to psychological test items were studied with 271 Australian college students. Findings suggest that confidence ratings, like the accuracy scores from the tests of human abilities, are stable and reliable measures of between-subjects variability. (SLD)