Fig. 1

The course of crystallized and fluid cognitive functions across the lifespan adapted from Baltes (1987) basing on the theory of intelligence proposed by Cattell (1963). The black solid curve indicates improvement of crystallized abilities like language and knowledge. The black dotted curve reflects age-related decline of fluid cognitive functions like working memory, attention, speed of processing, etc. The slim dotted limiting curves indicate the large interindividual variability of the fluid functions with increasing age. The fat, punctured black curve reflects continuous improvement of social competencies with age, adapted from Grossmann et al. (2010). The gray solid line indicates the course of sensory functions (vision and hearing) adapted from Baltes and Lindenberger (1997). The gray dotted curve indicates a hypothetical course of motor functions like motor speed and motor skills