One of the difficulties in interpreting the relation between fertility and measured intelligence is the possible influence of birth order. Penrose (1963), among others, has recognized that a negative correlation between sibship size and intelligence would result if birth order and intelligence were also negatively correlated. For various reasons most observations on birth order and intelligence...

The proposal that age-related differences in some measures of speed of performance may not be independent of the age-related differences in other measures of speed of performance has been associated with considerable controversy. Because converging evidence can often resolve this type of controversy, correlation-based procedures are proposed to distinguish general (or common) and specific (or u...

Two experiments investigated the influence of top-down information on adult age differences in the ability to search for singleton targets using spatial cues. In Experiment 1, both younger and older adults were equally able to use target-related top-down information (target feature predictability) to avoid attentional capture by uninformative (25% valid) cues. However, during informative (75% v...