Several differences in experimental design may contribute to why we found an advantage for learning
trochaic (high probability) labels, whereas Floccia and colleagues (2011) found no trochaic bias for
detecting phonemic detail in minimal pair object labels. Because the experiments investigated different
ways in which prosodic and phonemic information interacts, the labels varied in several important
phonological characteristics (e.g., labels contrasted by a single phoneme or multiple phonemes, phonotactic
manipulations). For example, if our labels had been minimal pairs, the effect of stress might
not have appeared; infants’ processing of minimal pairs can differ from processing of labels that are
more phonetically distinct because learning minimal pairs requires close attention to phonemic detail
as well as associating word forms with objects (e.g., Werker et al., 1998, 2002). In addition, Floccia and
colleagues’ (2011) task involved interactions between a child and an adult, and the labels were
embedded in naturalistic naming events and in natural sentences. With support from the social and
linguistic contexts, young children may learn iambic labels at rates similar to trochaic labels (at least
when labels are differentiated by phonemes in their stressed syllables) because they rely less on facilitation
from prior knowledge of native language sound patterns. The Switch Task used in the current
experiment provides minimal social and linguistic support, potentially allowing for a stronger influence
of word form characteristics. Furthermore, the participants in Floccia and colleagues’ experiments
were somewhat older (18.3–25.7 months) than our participants (18.8–20.3 months). More
skilled word learners may easily acquire a wider range of words than less skilled learners and may
require less support from characteristics such as common lexical stress patterns.