Biomedical subjects
Publications and source records attributed to D Z Hambrick.
I have a little dog, a little Maltese dog, Billy Byrd. He is approaching his 14th birthday. If I ever saw in this world anything that was made by the Creator's hand that is more dedicated, more true, more undeviant, more faithful than this little dog, I am at a loss to state what it is . . .We love that little dog. (Robert S. Byrd, U.S. Senator).
Four studies, each with approximately 200 adults between the ages of 18 and 80, were conducted to address two major goals. The first goal was to examine the relative contributions of different factors to the successful solution of crossword puzzles. Correlations and structural equation analyses revealed that general knowledge is the strongest predictor of crossword puzzle proficiency. Surprisingly, abstract reasoning ability, as measured by several different tests, had no direct relation to puzzle proficiency. The second goal of the project was to examine moderators of the relations between age and measures of both fluid and crystallized cognition. The results provide no evidence to suggest that amount of crossword puzzle experience reduces age-related decreases in fluid cognition or enhances age-related increases in crystallized cognition.
Analyses of new data and of previously published data were conducted to examine the degree to which age-related variance was shared across cognitive and noncognitive variables and to investigate possible alterations in the composition of a factor common to all variables as a function of age. The results indicated that measures of visual acuity, grip strength, and blood pressure shared age-related variance with measures of perceptual speed, episodic memory, spatial visualization, and inductive reasoning. However, although the cognitive variables shared similar amounts of variance in age-restricted and age-partialed analyses, the variance shared between cognitive and noncognitive variables was substantially reduced after controlling the influence of age.
It has recently been suggested that a large proportion of the age-related influences on many measures of cognitive functioning is mediated through a single common factor. This hypothesis has been supported by the discovery that much of the age-related variance in different cognitive measures is shared, and is not distinct or independent. These earlier results were replicated in this project, and it was also discovered that measures of corrected visual acuity and processing speed share a very large proportion of the age-related variance in measures of working memory, associative learning, and concept identification. The apparent implication is that the common factor that appears to contribute to age-related differences in many cognitive measures is quite broad and may reflect a relatively general reduction in central nervous system functioning.