The mismeasurement of mind: How neuropsychological testing creates a false picture of cognitive aging

Age-related declines in scores on neuropsychological tests are widely believed to reveal that human cognitive capacities decline across the lifespan. In a computational simulation, we show how the behavioral patterns observed in Paired Associate Learning (PAL), a particularly sensitive measure of age-related performance change (Rabbitt & Lowe, 2000), are predicted by the models used to formalize associative learning processes in other areas of behavioral and neuroscientific research. The simulation further predicts that manipulating language exposure will reproduce the experience-related performance differences erroneously attributed to age-related decline in age-matched adults. Consistent with this, older bilinguals outperformed native speakers in a German PAL test, an advantage that increased with age. These analyses and results show that age-related PAL performance changes reflect the predictable effects of learning on the associability of test items, and indicate that failing to control for these effects is distorting our understanding of cognitive and brain development in adulthood.