Earlier literature proposes two ways phonological similarity could harm imm
ediate recall: (I) It could increase the degradation of the representations
of items in memory, or (2) it could decrease the probability that a degrad
ed representation is correctly reconstructed. A multinomial processing tree
model for each hypothesis was used to analyze an immediate recall experime
nt. Both gave a good account of the data, but, of the two, results favor th
e hypothesis that the effect of phonological similarity is to impair recons
truction of degraded representations. A second issue is whether positions o
f repeated phonemes in phonologically similar items matter. We found that m
ere repetition of phonemes produced a phonological similarity effect. Repea
ted phonemes in the same positions appeared to produce a greater effect. A
final finding is that when reading rate was preequated, phonological simila
rity affected memory span by changing the time taken to recall a list of sp
an length.