Age and sex differences in sensitivity and response bias in a weight discrimination task

Forty young adults (18 to 31 years) and 40 older adults (61 to 82 years) participated in weight discrimination study. The subject's task was to decide if two weights lifted successively were the same or different and to rate the decision confidence of each response. The standard weight was 210 grams and the comparison weight was either 210 or 225 grams. It was found that the younger adults discriminated between the pair of weights better than the older adults and that men discriminated better than women, but an age by sex interaction was not observed. With regard to d, much of the age difference rested with older men being less sensitive than younger men at two of five rating scale categories. There was a tendency for older adults to set stricter criteria than young adults, but this was seen only when age groups differing in sensitivity were compared. When matched for sensitivity, age differences in response bias were not found. When shifts in response bias were observed it was such that young men set higher criteria than old men at the first category of the rating scale and lower criteria at the fifth category.