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ABSTRACT: We used eye movement measures of first-language (L1) and second-language (L2) paragraph reading to investigate whether the degree of current L2 exposure modulates the relative size of L1 and L2 frequency effects (FEs). The results showed that bilinguals displayed larger L2 than L1 FEs during both early- and late-stage eye movement measures, which are taken to reflect initial lexical access and postlexical access, respectively. Moreover, the magnitude of L2 FEs was inversely related to current L2 exposure, such that lower levels of L2 exposure led to larger L2 FEs. In contrast, during early-stage reading measures, bilinguals with higher levels of current L2 exposure showed larger L1 FEs than did bilinguals with lower levels of L2 exposure, suggesting that increased L2 experience modifies the earliest stages of L1 lexical access. Taken together, the findings are consistent with implicit learning accounts (e.g., Monsell, 1991), the weaker links hypothesis (Gollan, Montoya, Cera, Sandoval, Journal of Memory and Language, 58:787-814, 2008), and current bilingual visual word recognition models (e.g., the bilingual interactive activation model plus [BIA+]; Dijkstra & van Heuven, Bilingualism: Language and Cognition, 5:175-197, 2002). Thus, amount of current L2 exposure is a key determinant of FEs and, thus, lexical activation, in both the L1 and L2.
Psychonomic Bulletin & Review 02/2012; 19(1):73-80. · 2.61 Impact Factor
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ABSTRACT: Bilingual language production requires that speakers recruit inhibitory control (IC) to optimally balance the activation of more than one linguistic system when they produce speech. Moreover, the amount of IC necessary to maintain an optimal balance is likely to vary across individuals as a function of second language (L2) proficiency and inhibitory capacity, as well as the demands of a particular communicative situation. Here, we investigate how these factors relate to bilingual language production across monologue and dialogue spontaneous speech. In these tasks, 42 English-French and French-English bilinguals produced spontaneous speech in their first language (L1) and their L2, with and without a conversational partner. Participants also completed a separate battery that assessed L2 proficiency and inhibitory capacity. The results showed that L2 vs. L1 production was generally more effortful, as was dialogue vs. monologue speech production although the clarity of what was produced was higher for dialogues vs. monologues. As well, language production effort significantly varied as a function of individual differences in L2 proficiency and inhibitory capacity. Taken together, the overall pattern of findings suggests that both increased L2 proficiency and inhibitory capacity relate to efficient language production during spontaneous monologue and dialogue speech.
Frontiers in psychology. 01/2012; 3:57.
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ABSTRACT: Libben and Titone (2009) recently observed that cognate facilitation and interlingual homograph interference were attenuated by increased semantic constraint during bilingual second language (L2) reading, using eye movement measures. We now investigate whether cross-language activation also occurs during first language (L1) reading as a function of age of L2 acquisition and task demands (i.e., inclusion of L2 sentences). In Experiment 1, participants read high and low constraint English (L1) sentences containing interlingual homographs, cognates, or control words. In Experiment 2, we included French (L2) filler sentences to increase salience of the L2 during L1 reading. The results suggest that bilinguals reading in their L1 show nonselective activation to the extent that they acquired their L2 early in life. Similar to our previous work on L2 reading, high contextual constraint attenuated cross-language activation for cognates. The inclusion of French filler items promoted greater cross-language activation, especially for late stage reading measures. Thus, L1 bilingual reading is modulated by L2 knowledge, semantic constraint, and task demands.
Journal of Experimental Psychology Learning Memory and Cognition 07/2011; 37(6):1412-31. · 2.85 Impact Factor
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ABSTRACT: Semantic priming has long been used to investigate how concepts and ideas are related at the level of language, and has become a convenient tool for assessing conceptual and semantic dysfunction in cognitive disorders, including schizophrenia. The study of semantic priming in schizophrenia has led to diverse results: enhanced priming, reduced priming, and priming equivalent to that found in nonpsychiatric comparison groups. A number of hypotheses have been proposed to explain some of the observed deficits in schizophrenia patients. For example, difficulties in word recognition may be due to hyperactivation of too many lexical representations or to a failure to inhibit lexical competitors. One way to distinguish between these possible explanations is to move beyond reliance on behavior alone and to examine the neural processes involved in lexical recognition. Here we present a magnetoencephalographic study of semantic priming in schizophrenia. Importantly, schizophrenia patients and healthy controls did not differ in performance on a priming task. We show that normal behavioral performance can occur in a context of aberrant neural responses. These findings suggest that normal behavioral responses in schizophrenia can be achieved through neural mechanisms that differ from those seen in the psychiatrically well brain.
Journal of Neurolinguistics 05/2010; 23(3):223-239. · 1.97 Impact Factor
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ABSTRACT: Thought disorder as well as language and communication disturbances are associated with schizophrenia and are over-represented in clinically unaffected relatives of schizophrenics. All three kinds of dysfunction involve some element of deviant verbalizations, most notably, semantic anomalies. Of particular importance, thought disorder characterized primarily by deviant verbalizations has a higher recurrence in relatives of schizophrenic patients than schizophrenia itself. These findings suggest that deviant verbalizations may be more penetrant expressions of schizophrenia susceptibility genes than schizophrenia. This paper reviews the evidence documenting the presence of thought, language and communication disorders in schizophrenic patients and in their first-degree relatives. This familial aggregation potentially implicates genetic factors in the etiology of thought disorder, language anomalies, and communication disturbances in schizophrenia families. We also present two examples of ways in which thought, language and communication disorders can enrich genetic studies, including those involving schizophrenia.
Journal of Neurolinguistics 05/2010; 23(3):176-192. · 1.97 Impact Factor
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ABSTRACT: The capacity for transitive inference (TI), a form of relational memory organization, is impaired in schizophrenia patients. In order to disambiguate deficits in TI from the effects of ambiguous reinforcement history and novelty, 28 schizophrenia and 20 nonpsychiatric control subjects were tested on newly developed TI and non-TI tasks that were matched on these 2 variables. Schizophrenia patients performed significantly worse than controls on the TI task but were able to make equivalently difficult nontransitive judgments as well as controls. Neither novelty nor reinforcement ambiguity accounted for the selective deficit of the patients on the TI task. These findings implicate a disturbance in relational memory organization, likely subserved by hippocampal dysfunction, in the pathophysiology of schizophrenia.
Schizophrenia Bulletin 06/2009; 36(6):1187-200. · 8.80 Impact Factor
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ABSTRACT: The neural bases of prosody during the production of literal and idiomatic interpretations of literally plausible idioms was investigated. Left- and right-hemisphere-damaged participants and normal controls produced literal and idiomatic versions of idioms (He hit the books.) All groups modulated duration to distinguish the interpretations. LHD patients, however, showed typical speech timing difficulties. RHD patients did not differ from the normal controls. The results partially support a differential lateralization of prosodic cues in the two cerebral hemispheres [Van Lancker, D., & Sidtis, J. J. (1992). The identification of affective-prosodic stimuli by left- and right-hemisphere-damaged subjects: All errors are not created equal. Journal of Speech and Hearing Research, 35, 963-970]. Furthermore, extended final word lengthening appears to mark idiomaticity.
Brain and Language 03/2009; 110(1):38-42. · 3.12 Impact Factor
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ABSTRACT: Studies of polysemy are few in number and are contradictory. Some have found differences between polysemy and homonymy (L. Frazier & K. Rayner, 1990), and others have found similarities (D. K. Klein & G. Murphy, 2001). The authors investigated this issue using the methods of D. K. Klein and G. Murphy (2001), in whose study participants judged whether ambiguous words embedded in word pairs (e.g., tasty chicken) made sense as a function of a cooperating, conflicting, or neutral context. The ambiguous words were independently rated as having low, moderate, or highly overlapping senses to approximate a continuum from homonymy to metonymic polysemy. The effects of meaning dominance were examined. Words with highly overlapping meanings (e.g., metonymy) showed reduced effects of context and dominance compared with words with moderately or low overlapping meanings (e.g., metaphorical polysemy and homonymy). These results suggest that the comprehension of ambiguous words is mediated by the semantic overlap of alternative senses/meanings.
Journal of Experimental Psychology Learning Memory and Cognition 11/2008; 34(6):1534-43. · 2.85 Impact Factor
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ABSTRACT: Relational memory, the flexible ability to generalize across existing stores of information, is a fundamental property of human cognition. Little is known, however, about how and when this inferential knowledge emerges. Here, we test the hypothesis that human relational memory develops during offline time periods. Fifty-six participants initially learned five "premise pairs" (A>B, B>C, C>D, D>E, and E>F). Unknown to subjects, the pairs contained an embedded hierarchy (A>B>C>D>E>F). Following an offline delay of either 20 min, 12 hr (wake or sleep), or 24 hr, knowledge of the hierarchy was tested by examining inferential judgments for novel "inference pairs" (B>D, C>E, and B>E). Despite all groups achieving near-identical premise pair retention after the offline delay (all groups, >85%; the building blocks of the hierarchy), a striking dissociation was evident in the ability to make relational inference judgments: the 20-min group showed no evidence of inferential ability (52%), whereas the 12- and 24-hr groups displayed highly significant relational memory developments (inference ability of both groups, >75%; P < 0.001). Moreover, if the 12-hr period contained sleep, an additional boost to relational memory was seen for the most distant inferential judgment (the B>E pair; sleep = 93%, wake = 69%, P = 0.03). Interestingly, despite this increase in performance, the sleep benefit was not associated with an increase in subjective confidence for these judgments. Together, these findings demonstrate that human relational memory develops during offline time delays. Furthermore, sleep appears to preferentially facilitate this process by enhancing hierarchical memory binding, thereby allowing superior performance for the more distant inferential judgments, a benefit that may operate below the level of conscious awareness.
Proceedings of the National Academy of Sciences 05/2007; 104(18):7723-8. · 9.68 Impact Factor
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ABSTRACT: Delusions may arise from abnormalities in emotional perception. In this study, we tested the hypothesis that delusional schizophrenia patients are more likely than non-delusional schizophrenia patients and healthy participants to assign affective meanings to neutral stimuli.
Unpleasant, pleasant, and neutral words were randomly presented to three subject groups--patients with schizophrenia with prominent delusions, patients with schizophrenia without delusions, and healthy participants. Participants performed three tasks: one in which they decided whether a letter string was a word or a non-word (lexical decision) and two affective classification tasks in which they judged whether words were 1) neutral or unpleasant, or 2) neutral or pleasant.
While there were no significant between-group differences in lexical decision performance, patients with delusions showed selective performance deficits in both affective classification tasks. First, delusional patients were significantly more likely than non-delusional patients and healthy participants to classify words as unpleasant. Second, delusional patients took significantly longer than both other groups to correctly classify neutral words in both affective classification tasks.
Taken together, these findings suggest that delusions are associated with the explicit misattribution of salience to neutral stimuli.
Schizophrenia Research 05/2006; 83(2-3):247-56. · 4.75 Impact Factor
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ABSTRACT: Activity in the hippocampus is modulated by novelty detection, and by the processing of conjunctions between two stimuli. We investigated whether the hippocampus is activated by discrimination of stimulus-stimulus relationships in novel versus familiar pairs of visual stimuli in 15 healthy subjects using functional magnetic resonance imaging. Subjects were asked to recognize the previously rewarded stimulus in each case. We found significantly greater activation of the right hippocampus when discriminating previously seen compared with novel pairs of visual stimuli. This activation was evident in individual subjects and was not related to stimulus novelty, reward contingency, or task instruction. Right hippocampal activation during discrimination of previously seen pairs of objects was correlated with activity in the anteromedial thalamus, cingulate cortex, and contralateral hippocampus.
Psychiatry Research 09/2005; 139(3):191-8. · 2.52 Impact Factor
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American Journal of Psychiatry 05/2005; 162(4):663. · 12.54 Impact Factor
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ABSTRACT: Transitive inference (TI) describes a fundamental operation of relational (e.g., explicit) memory organization [Eichenbaum, H., Cohen, N.J., 2001. From Conditioning to Conscious Recollection: Memory Systems of the Brain. Oxford Univ. Press]. Here we investigate TI in schizophrenia (SZ), a neurocognitive disorder associated with explicit but not implicit memory dysfunction. SZ patients and healthy controls were trained on a series of learned discriminations that were hierarchically organized (A>B, B>C, C>D, and D>E). They were then tested on each training pair and two novel "inference" pairs: AE, which can be evaluated without consideration of hierarchical relations, and BD, which can only be evaluated by hierarchical relations. SZ patients and controls successfully learned the training pairs and correctly responded to the nonrelational AE pairs. However, SZ patients were less accurate than controls in responding to the relational BD pairs, consistent with the hypothesis that higher-level memory processes associated with relational memory organization are impaired in SZ. The results are discussed with respect to the relational memory model and candidate neuro-cognitive mechanisms of TI.
Schizophrenia Research 07/2004; 68(2-3):235-47. · 4.75 Impact Factor
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ABSTRACT: Schizophrenia (SZ) is a disorder associated with dysfunction of the neural substrate involved in lexical processing, the superior temporal lobe (STL). We examined whether the detrimental effects of lexical competition on word identification are exaggerated in SZ. The results showed that SZ patients were less able than controls to identify words coming from high lexical competitor environments (i.e., high density and high frequency lexical neighborhoods). They did not differ from controls, however, in identifying words coming from low lexical competitor environments (i.e., low density and low frequency lexical neighborhoods). Further, when SZ patients misidentified high competitor words, the erroneously reported words were of a significantly higher frequency than those reported by controls when they misidentified high competitor words (i.e., the HF misidentification bias). Identification accuracy for high competitor words negatively correlated with amount of thought disorder, and the HF misidentification bias positively correlated with the lifetime frequency and severity of auditory hallucinations, the latter of which serving as presumed independent measures of STL dysfunction in SZ.
Schizophrenia Research 06/2004; 68(1):75-85. · 4.75 Impact Factor
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ABSTRACT: Studies in rodents have demonstrated that the integration and flexible expression of memories, necessary for transitive inference, depend on an intact hippocampus. To test this hypothesis in humans, we studied brain activation during the discrimination of a series of overlapping and non-overlapping arbitrary visual stimulus pairs. We report that transitive inference about overlapping pairs is associated with right anterior hippocampal activation, whereas recognition of non-overlapping stimulus pairs is associated with bilateral medial temporal lobe activation centered in the anterior parahippocampal gyrus. We conclude that immediate access to simple stimulus-stimulus relationships is mediated via the parahippocampal gyrus, whereas the flexible representation of memory requires the recruitment of the hippocampus.
Hippocampus 02/2004; 14(2):153-62. · 5.18 Impact Factor
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ABSTRACT: Schizophrenia patients have difficulty processing nonliteral forms of discourse such as idiomatic expressions. We hypothesized that schizophrenia patients would show impaired idiom processing for literally plausible idioms (e.g., kick the bucket) but not for literally implausible idioms (e.g., be on cloud nine). Thirty-two patients and 36 controls listened to sentences containing literally plausible and implausible idioms and made lexical decisions about idiom-related or literal-related targets. Schizophrenia patients showed reduced priming for literally plausible idioms but intact priming for literally implausible idioms compared with controls. Both groups showed evidence of literal word priming. These results are consistent with the notion that schizophrenia patients make normal use of context under conditions that minimize the need for controlled processing.
Journal of Abnormal Psychology 06/2002; 111(2):313-20. · 4.86 Impact Factor
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ABSTRACT: It has often been reported that older listeners have difficulty discriminating between phonetically similar items, but may rely on contextual cues as a compensatory mechanism. The present study examined the effects of different degrees of semantic bias on speech perception in groups of younger and older listeners. Stimuli from two /g/-/k/ voice onset time (VOT) continua were presented at the end of biasing and neutral sentences. Results indicated that context strongly influenced phonetic identification in older listeners; this was true for younger listeners only in the case of less-than-ideal stimuli. Findings are discussed in relation to theories concerning age-related changes in speech processing.
Experimental Aging Research 34(3):232-50. · 1.31 Impact Factor
