| Neuro-cognitive researchers have worked to establish the nature of hemispheric processing differences (Chiarello, 1985), representational differences (Chiarello, Burgess, Richards, & Pollock, 1990; Beeman, 1993), and the effect of timecourse on meaning retrieval in the cerebral hemispheres (Burgess & Simpson, 1988a; Burgess, Atchley, Audet, & Arambel, 1994). Experiment 1 was designed to obtain a normative hierarchical list of semantic features that define a list of 56 unambiguous nouns. Experiment 2, a divided visual field (DVF) priming experiment, was designed to determine what kinds of semantic feature based information are active in the two cerebral hemispheres across the timecourse of meaning retrieval. Experiment 3 explored the effect of context on priming by presenting subjects with a biasing context word along with the priming noun. The results from Experiment 2 suggest that the left hemisphere (LH) shows early activation for all semantic features. Later in the timecourse of activation, the LH shows activation for both strongly and weakly associated features that are related to the dominant representation of the priming concept. However, there is no activation for incompatible subordinate information. As with previous research, later in the timecourse of meaning retrieval, the right hemisphere (RH) activates all related semantic features. The Experiment 3 data replicate and extend the results found in Experiment 2 for the LH. The LH maintains activation for all information that is compatible with the dominant representation and shows no additional influence from the context word. The RH activates all semantic features at the longer processing duration. Furthermore, the RH shows an additional increase in priming magnitude when the context word and target word are from the same feature class. On the basis of these results, the role of the LH seems to be to select a single representation. This representation contains both highly associated and weakly associated information. In contrast, the RH maintains activation for all semantic feature information (regardless of the compatibility with the dominant representation). Additionally, in the RH contextual information influences the pattern of priming, so that feature class consistent context information shows greater activation as early as during lexical access. |
