Date of Award


Degree Type


Degree Name

Doctor of Philosophy


The purpose of this research was to identify stimulus characteristics that influence the ease of picture naming in children. Naming is a basic aspect of language behavior that includes such components as object identification, selection of an appropriate name, and generation of the naming response. Little is known about factors that influence the proficiency with which these components are executed. This research attempted to isolate the effects on naming efficiency of: (a) the number of available correct names for a picture (referential uncertainty) and (b) the degree to which a picture realistically represents the depicted object (stimulus realism).;Results from three experiments demonstrated that: (a) objects with several acceptable names (high uncertainty) were named more slowly than those with a single dominant name (low uncertainty), and (b) this effect arose at a post-identification phase of naming. In Experiment 1, 120 children (ages 4;5 to 7;8) made naming or object decision responses to pictures that varied in referential uncertainty. Uncertainty influenced naming but not object decision reaction times, suggesting that it affected a post-identification phase of processing unique to naming. Experiment 3 replicated this effect of uncertainty on naming using the same stimuli with another sample of 72 children (ages 6;7 to 8;6). Experiment 2 employed an experimental manipulation of uncertainty. Children (48 Ss, ages 6;11 to 8;6) learned novel names for two unfamiliar objects, one paired with a single name (low uncertainty), the other paired with two names (high uncertainty). Again, naming times for high uncertainty objects exceeded those for low uncertainty objects. Possible mechanism for the uncertainty effect include passive diffusion of activation over multiple object-name pathways or active inhibition among competing candidate names.;The experiments also assessed the effects on naming of stimulus realism. In each experiment, subjects responded to both realistic (colored photographs) and abstract (uncolored line drawings) pictures of the same objects. No conclusive evidence emerged for an effect of stimulus realism on naming.;The results demonstrate that the availability of several possible names for an object increases the difficulty of a post-identification phase of naming. Future research should determine the underlying mechanism responsible for this uncertainty effect.



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