Individual differences in a positional learning task across the adult lifespan

This study aimed at modeling individual and average non-linear trajectories of positional learning using a structured latent growth curve approach. The model is based on an exponential function which encompasses three parameters: Initial performance, learning rate, and asymptotic performance. These learning parameters were compared in a positional learning task administered to a sample comprising the whole adult lifespan (N = 527; age range: 20 years to 89.3 years; Mage = 52.95, SDage = 17.37). Additionally, three explanatory variables, age, speed of information processing, and educational level were included in the analyses. All three learning parameters showed reliable individual differences. The correlations between the learning parameters indicated that those participants with high learning rates needed more trials to achieve their asymptotic performance and those who recalled more items initially also had a higher asymptotic performance. Older persons showed lower initial performance and lower asymptotic performance, whereas speed of information processing was positively associated only with initial performance. Persons with more years of formal education had a higher initial performance and a higher asymptotic performance. The learning rate, in turn, appeared to be unaffected by all three predictor variables.