Cohort theory, developed by Marslen-Wilson and Welsh (1978), proposes that a "cohort" of all the words beginning with a particular sound sequence will be activated during the initial stage of the word recognition process. We used a priming technique to test specific predictions regarding cohort activation in three experiments. In each experiment, subjects identified target words embedded in noise at different signal-to-noise ratios. The target words were either presented in isolation or preceded by a prime item that shared phonological information with the target. In Experiment 1, primes and targets were English words that shared zero, one, two, three, or all phonemes from the beginning of the word. In Experiment 2, nonword primes preceded word targets and shared initial phonemes. In Experiment 3, word primes and word targets shared phonemes from the end of a word. Evidence of reliable phonological priming was observed in all three experiments. The results of the first two experiments support the assumption of activation of lexical candidates based on word-initial information, as proposed in cohort theory. However, the results of the third experiment, which showed increased probability of correctly identifying targets that shared phonemes from the end of words, did not support the predictions derived from the theory. The findings are discussed in terms of current models of auditory word recognition and recent approaches to spoken-language understanding.The perception and comprehension of spoken language involves a complex interaction among several different sources of linguistic information. To comprehend a sentence, a listener must analyze the phonetic, lexical, syntactic, semantic, and pragmatic information encoded in the speech waveform. Word perception is clearly a critical part of the comprehension process because words provide the interface between the perceptual processing of stimulus information and the conceptual interpretation of an utterance. In principle, it is possible to distinguish two functionally different processes that subserve word perception: word recognition and lexical access. Although there are no standard or widely agreed-upon definitions for these terms, we can define word recognition as the pattern recognition process that allows a listener to identify a spoken or printed stimulus as a word and lexical access as the process that mediates access to abstract knowledge (e.g., syntactic, semantic, pragmatic information) about a lexical entry (see Pisoni & Luce, in press). Note that making this theoretical distinction does not require that these processes operate as autonomous modules (cf. Fodor, 1983;Forster, 1978); rather it serves only to partition word perception into separate cognitive operations that are theoretically quite different.Over the last few years, there has been an increased interest in the processes that mediate perception of spoken words (Cole, 1980;Cole & Rudnicky, 1983) and three general findings have emerged from this work (see Cole & Jakimik, 1980;Foss & Blank...