A long-standing hypothesis is that rapid automatized naming (RAN) measures access to phonological representations stored in long-term memory, but this has been difficult to test experimentally because phonological representations are mental constructs not easily operationalized. Here, we provide a method to test this theory using rime neighborhood density as an index of phonological representational strength. Thirty adults completed four picture-naming tasks orthogonalized for item composition (repeating vs. nonrepeating) and presentation format (discrete vs. serial). Each task was presented in two dichotomous conditions of rime neighborhood density (dense and sparse). There was no effect of rime neighborhood density on naming speed in the discrete nonrepeated (confrontation naming) task. However, rime neighborhood density significantly facilitated naming speed for serial repeated (i.e., RAN), discrete repeated, and serial nonrepeated tasks (ps<.03). The effect was weakest for confrontation naming (d=0.14) and strongest for both discrete and serial RAN tasks (ds=1.01), suggesting that repeating items, not serial presentation, makes RAN uniquely sensitive to manipulations of rime neighborhood density and, by proxy, phonological representations.

Confrontation naming ability entails the operation of distinct cognitive operations and the integrity of a distributed neural network. Previous research has indicated a critical role for the left temporal lobe region in naming ability, but there is less agreement about the relative role of distinct temporal lobe regions. In the current paper, we used quantitative MR volumetrics to investigate the relative contribution of the hippocampus and extrahippocampal temporal lobe (segmented gray and white matter) volumes to confrontation naming performance in 53 patients with temporal lobe epilepsy. Findings showed (1) a stronger relationship for left temporal lobe volume than right temporal lobe volume in predicting naming performance; (2) both left temporal lobe white matter volume and left hippocampus volume contributed a significant amount of unique variance to spontaneous naming performance; and (3) left temporal lobe white matter volume but not left hippocampus volume predicted recognition naming performance. (JINS, 2005, 11, 358–366.)