Alphabetic search: Comment on Klahr, Chase, and Lovelace (1983).

Response time (RT) curves were obtained from Ss who were instructed to search for following or preceding letters in the alphabet with respect to given stimulus letters. To describe the shape of these curves, D. Klahr et al (see record 1984-05777-001) proposed a search model. It was assumed that the alphabet was internally represented by a number of chunks of a few letters. Klahr et al assumed that serial searches occurred along 2 hierarchical levels: (1) a search for the correct chunk and (2) a search of the letters within the chunk. The Klahr et al model predicted an ascending sawtooth-shaped RT curve. However, according to the authors' analysis of the data, the RT curves did not show the expected sawtooth shapes. In order to find out whether the lack of empirical support for the model was an artifact of averaging the data, the experiment was replicated. It was found that individual RT curves did not show the shape characteristics that were predicted by the Klahr et al model either. The data supported the hypothesis that the access of letters was direct without any hierarchy, and that the retrieval of successive letters was determined by the variable associations between subsequent letters. (PsycINFO Database Record (c) 2010 APA, all rights reserved)