Associations between Birth Order and Personality Traits: Evidence from Self-Reports and Observer Ratings

Sulloway (1996) proposed that personality traits developed in childhood mediate the association of birth order with scientific radicalism. Birth-order effects on traits within the five-factor model of personality were examined in three studies. Self-reports on brief measures of Neuroticism, Extraversion, and Openness in a national sample (N= 9664) were unrelated to birth order. Self-reports on the 30 facet scales of the Revised NEO Personality Inventory (NEO-PI-R) in an adult sample (N= 612) showed only small effects for Altruism and Tender-Mindedness. Peer ratings (N= 166) supported the hypotheses that laterborn children would be higher in facets of Openness and Agreeableness, but spouse ratings (N= 88) did not replicate those findings. Birth order may have subtle effects on perceived personality, but it is unlikely that this effect mediates associations with scientific radicalism.     

Age differences in the perception of hierarchical structure in events

Everyday activities break down into parts and subparts, and appreciating this hierarchical structure is an important component of understanding. In two experiments we found age differences in the ability to perceive hierarchical structure in continuous activity. In both experiments, younger and older adults segmented movies of everyday activities into large and small meaningful events. Older adults’ segmentation deviated more from group norms than did younger adults’ segmentation, and older adults’ segmentation was less hierarchically organized than that of younger adults. Older adults performed less well than younger adults on event memory tasks. In some cases, measures of event segmentation discriminated between those older adults with better and worse memory. These results suggest that the hierarchical encoding of ongoing activity declines with age, and that such encoding may be important for memory.