Reading is one of the most popular leisure activities and it is routinely
performed by most individuals even in old age. Successful reading enables
older people to master and actively participate in everyday life and maintain
functional independence. Yet, reading comprises a multitude of subprocesses
and it is undoubtedly one of the most complex accomplishments of the human
brain. Not surprisingly, findings of age-related effects on word recognition
and reading have been partly contradictory and are often confined to only one
of four central reading subprocesses, i.e., sublexical, orthographic,
phonological and lexico-semantic processing. The aim of the present study was
therefore to systematically investigate the impact of age on each of these
subprocesses. A total of 1,807 participants (young, N = 384; old, N = 1,423)
performed four decision tasks specifically designed to tap one of the
subprocesses. To account for the behavioral heterogeneity in older adults,
this subsample was split into high and low performing readers. Data were
analyzed using a hierarchical diffusion modeling approach, which provides more
information than standard response time/accuracy analyses. Taking into account
incorrect and correct response times, their distributions and accuracy data,
hierarchical diffusion modeling allowed us to differentiate between age-
related changes in decision threshold, non-decision time and the speed of
information uptake. We observed longer non-decision times for older adults and
a more conservative decision threshold. More importantly, high-performing
older readers outperformed younger adults at the speed of information uptake
in orthographic and lexico-semantic processing, whereas a general age-
disadvantage was observed at the sublexical and phonological levels. Low-
performing older readers were slowest in information uptake in all four
subprocesses. Discussing these results in terms of computational models of
word recognition, we propose age-related disadvantages for older readers to be
caused by inefficiencies in temporal sampling and activation and/or inhibition
processes