  The ungrammatical sentence "The key to the cabinets are on the table" is
known to lead to an illusion of grammaticality. As discussed in the
meta-analysis by Jaeger et al., 2017, faster reading times are observed at the
verb are in the agreement-attraction sentence above compared to the equally
ungrammatical sentence "The key to the cabinet are on the table". One
explanation for this facilitation effect is the feature percolation account:
the plural feature on cabinets percolates up to the head noun key, leading to
the illusion. An alternative account is in terms of cue-based retrieval (Lewis
& Vasishth, 2005), which assumes that the non-subject noun cabinets is
misretrieved due to a partial feature-match when a dependency completion
process at the auxiliary initiates a memory access for a subject with plural
marking. We present evidence for yet another explanation for the observed
facilitation. Because the second sentence has two nouns with identical number,
it is possible that these are, in some proportion of trials, more difficult to
keep distinct, leading to slower reading times at the verb in the first
sentence above; this is the feature overwriting account of Nairne, 1990. We
show that the feature overwriting proposal can be implemented as a finite
mixture process. We reanalysed ten published data-sets, fitting hierarchical
Bayesian mixture models to these data assuming a two-mixture distribution. We
show that in nine out of the ten studies, a mixture distribution corresponding
to feature overwriting furnishes a superior fit over both the feature
percolation and the cue-based retrieval accounts.
