Both sides get the point: Hemispheric sensitivities to sentential constraint

Abstract

Behavioral studies have consistently reported striking differences in the impact of sentence-level information on the processing of words presented in the right (RVF) versus the left (LVF) visual field, with context effects apparent only for RVF items. The consistent lack of such effects in the LVF has been taken to mean that right hemisphere language comprehension is largely insensitive to messagelevel meaning. We used the functional specificity afforded by event-related potential measures to assess this claim. Target words completing strongly and weakly constraining sentence contexts, in which constraint arose at the sentence level rather than from lexical associations, were presented laterally in the LVF or RVF. Increased constraint significantly reduced N400 amplitudes with presentation in both VFs, with no differences in the timing or amplitude of these effects. These results are inconsistent with the view that the VF asymmetries found in behavioral measures reflect differential hemispheric capacities at the level of semantic analysis and integration, although VF-based differences on earlier components (P2) suggest asymmetries in the impact of sentential context on perceptual aspects of word processing in the two hemispheres.

Multiple priming of lexically ambiguous and unambiguous targets in the cerebral hemispheres: The coarse coding hypothesis revisited

“…Furthermore, both hemispheres showed similar, task-dependent patterns of priming from lexical and semantic levels of representation (task effect). These findings suggest that cerebral asymmetries observed in other tasks must arise from alternative factors, such as the timecourse of activation (e.g., Koivisto 1997), the representation of different types of semantic relations (e.g., Richards and Chiarello 1995), the predictive use of context information (e.g., Federmeier and Kutas 1999;Federmeier, Mai et al 2005), or the efficacy of strategic, controlled semantic processing (e.g., Burgess and Simpson 1988). Follow-up studies that track asymmetries over time and across processing stages, for example using event related brain potential (ERP) methods, may help to adjudicate between these possibilities.…”

“…In turn, such differences could arise either because the two hemispheres actually represent these kinds of relationships differently (e.g., Deacon, GroseFifer, Yang, Stanick, Hewitt and Dynowska 2004) or because of more general asymmetries in how each hemisphere processes verbal information. For example, Federmeier and her colleagues (Federmeier and Kutas 1999;Federmeier, Mai et al 2005) have argued that the LH tends to use verbal information predictively whereas the RH integrates old information with new information in a more post-hoc fashion. Lexical association is typically defined by the tendency for one word to lead to the prediction/generation of another, whereas nonassociated, categorically related information will generally be much less predictable.…”

“…This raises the possibility that the result pattern could be influenced by asymmetries in how context information accrues over time and/or in what kind of task-related strategies are adopted (especially in the semantic judgment task, where noting a relationship between the two primes provides useful information about the upcoming response). Federmeier and her colleagues, for example, have argued that the LH, but not the RH, can use context information to predict features of likely upcoming words (Federmeier and Kutas 1999;Federmeier, Mai and Kutas 2005). Such prediction would be facilitated by the presence of multiple, interrelated primes.…”

The effects of context, meaning frequency, and associative strength on semantic selection: Distinct contributions from each cerebral hemisphere

“…Although word processing in both hemispheres seems to be influenced by the message-level meaning information available from a sentence context (e.g., Coulson et al, 2005;Faust, Bar-Lev, and Chiarello, 2003), context seems to affect processing in different ways in each (Federmeier andKutas, 1999, 2002;Federmeier, Mai, and Kutas, 2005;Wlotko and Federmeier, in press). In particular, the LH seems more likely to use the top-down information available from a sentence context to predict features of likely upcoming words, whereas processing in the RH seems to be more stimulus-driven and integrative in nature (see Federmeier, in press, for a more extensive discussion).…”

Finding the right word: Hemispheric asymmetries in the use of sentence context information

“…For example, Federmeier, Mai, and Kutas (2005) showed that for stimuli presented to either VF, there were nearly identical sentential constraint effects on the N400, a well-studied eventrelated potential (ERP) component that shows specific sensitivities to lexico-semantic manipulations (for a review, see Kutas & Federmeier, 2000). The N400 is thought to be generated bilaterally (perhaps with a greater left than right contribution) in a large portion of the temporal lobe (Van Petten & Luka, 2006), probably including perisylvian regions that correspond to Wernicke's area (and its homologue) as well as areas of the anterior medial temporal lobe associated with semantic memory.…”