Hypothesis
Speakers would name a pictured object faster in front of a person they had earlier linked with that object's name, as Horton (2007, Experiment 1) found.
What failed
Three experiments designed to replicate and extend Horton's Experiment 1 did not reproduce the effect.
Broken assumption
Memory links between a conversation partner and a word speed up naming in that partner's presence.
Why
The abstract does not give a cause.
From the published paper: Brown‐Schmidt et al. PLoS ONE, 2014. ↗CC BY