online learning from input versus offline memory evolution in adult word learning effects of neighborhood density and phonologically related practice purpose in this study the authors investigated adult word learning to determine how neighborhood density and practice across phonologically related training sets influence online learning from input during training versus offline memory evolution during notraining gapsmethod sixtyone adults were randomly assigned to learn low or highdensity nonwords within each density condition participants were trained on one set of words and then were trained on a second set of words consisting of phonological neighbors of the first set learning was measured in a picturenaming test data were analyzed using multilevel modeling and spline regressionresults steep learning during input was observed with new words from dense neighborhoods and new words that were neighbors of recently learned words ie secondset words being learned better than other words in terms of memory evolution large and significant forgetting was observed during 1week gaps in training effects of density and practice during memory evolution were opposite of those during input specifically forgetting was greater for highdensity and secondset words than for lowdensity and firstset wordsconclusion high phonological similarity regardless of source ie known words or recent training appears to facilitate online learning from input but seems to impede offline memory evolution