Biomedical subjects

Jeffrey S Bowers

Publications and source records attributed to Jeffrey S Bowers.

4 recordsLinked to original sources

PubMed2004

Is speech perception modular or interactive?

Norris et al. recently reported experimental evidence that listeners learn phoneme categories in response to lexical feedback. To reconcile these findings with their modular account of speech perception, the authors argue that top-down feedback can be used to support phoneme learning, but not to influence on-line phonemic processing. We suggest that these findings have broader implications than the authors assume, and we discuss potential challenges for integrating a modular theory with top-down learning.

Feedback↗

PubMed2003

In search of perceptual priming in a semantic classification task.

Four experiments tested for perceptual priming for written words in a semantic categorization task. Repetition priming was obtained for low-frequency words when unrelated categorizations were performed at study and test (Experiment 1), but it was not orthographically mediated given that written-to-written and spoken-to-written word priming was equivalent (Experiments 2 and 3). Furthermore, no priming was obtained between pictures and words (Experiment 4), suggesting that the nonorthographic priming was largely phonological rather than semantic. These results pose a challenge to standard perceptual theories of priming that should expect orthographic priming when words are presented in a visual format at study and test.

Adult↗

PubMed2003

Locus of semantic interference in picture-word interference tasks.

Picture-word interference studies typically show that semantically related distractor words embedded within a picture slow picture-naming responses, relative to unrelated ones. This semantic interference effect is commonly interpreted as arising from the competition of lexical-semantic (e.g., Schriefers, Meyer, & Levelt, 1990) or lexical-phonological (e.g., Starreveld & La Heij, 1996) codes. The experiment reported here tests a crucial assumption shared by these accounts--namely, that the effect reflects a lexical, rather than a nonverbal, conceptual conflict. Pictures were named while participants attempted to ignore embedded distractors that were in either verbal or pictorial format. The presence of both words and pictures substantially interfered with naming responses, but only words, not pictures, were found to induce semantic interference. These findings support the claim that for semantic interference to arise, both target picture and distractor have to be lexicalized. Consequently, a general conceptual locus of the effect can be excluded, and the claim that semantic interference is based on a lexical conflict is confirmed.

Adolescent↗

PubMed2002

Challenging the widespread assumption that connectionism and distributed representations go hand-in-hand.

One of the central claims associated with the parallel distributed processing approach popularized by D.E. Rumelhart, J.L. McClelland and the PDP Research Group is that knowledge is coded in a distributed fashion. Localist representations within this perspective are widely rejected. It is important to note, however, that connectionist networks can learn localist representations and many connectionist models depend on localist coding for their functioning. Accordingly, a commitment to distributed representations should be considered a specific theoretical claim regarding the structure of knowledge rather than a core principle, as often assumed. In this paper, it is argued that there are fundamental computational and empirical challenges that have not yet been addressed by distributed connectionist theories that are readily accommodated within localist approaches. This is highlighted in the context of modeling word and nonword naming, the domain in which some of the strongest claims have been made. It is shown that current PDP models provide a poor account of naming monosyllable items, and that distributed representations make it difficult for these models to scale up to more complex language phenomena. At the same time, models that learn localist representations are shown to hold promise in supporting many of the core reading and language functions on which PDP models fail. It is concluded that the common rejection of localist coding schemes within connectionist architectures is premature.

Cognitive Science↗