E. J. Wisniewski and G. L. Murphy (see record EJ689195) suggested that the apparent effects of relation frequency in C. L. Gagne and E. J. Shoben's (1997) conceptual combination experiments could be explained by differences between the familiarity and plausibility of their stimuli (noun-noun phrases). However, C. L. Gagne and T. L. Spalding argued that Wisniewski and Murphy's measures of plausibility and frequency are both sensitive to relation frequency. They also suggested that the stimuli were mostly novel, such that differences in familiarity could not explain Gagne and Shoben's findings. The current authors focus on the theoretical rationale for the plausibility and familiarity variables, arguing that the original interpretation of their findings is correct.