Selective adaptation of crossmodal speech information is not the result of higher-level stimulus associations

Selective adaptation of speech information can change perceptual categorization of ambiguous phonetic information (e.g., Vroomen and Baart, 2012). The results of a number of studies suggest that selective adaptation may depend on sensory-specific information shared between the adaptor and test stimuli (e.g., Roberts and Summerfield, 1981; Saldaña and Rosenblum, 1994). For example, adaptation to heard syllables can change perception of heard syllables, but adaptation to lipread syllables has not been found to significantly change perception of heard syllables. The lack of crossmodal influence in selective speech adaptation is inconsistent with other phenomena suggesting crossmodal influences occur early in the speech process (e.g., Rosenblum, 2008). For the current investigation, a replication of an attempt to induce crossmodal speech adaptation again failed to yield significant effects. However, a meta-analysis including these results with past attempts (Roberts and Summerfield, 1981) revealed that small crossmodal speech adaptation effects are significant across studies. Next, an attempt to induce crossmodal speech adaptation employing a much larger group of new participants did yield significant crossmodal adaptation effects. A replication using text-stimuli failed to induce similar adaptation effects, suggesting that the observed crossmodal effects are not the result of higher-level stimulus associations. The theoretical implications of these smaller crossmodal effects will be discussed.