Tolerating Ambiguity
Ambiguous Words Recruit the Left Inferior Frontal Gyrus in Absence of a Behavioral Effect
Abstract
Many models of word recognition predict a lexical ambiguity disadvantage in semantic categorization tasks (SCTs). However, recent evidence suggests that an ambiguity disadvantage in SCT results from a bias in the decision-making phase of the task and not in the meaning-activation phase: Behavioral effects of ambiguity disappear when these decision biases are controlled (Pexman, Hino, & Lupker, 2004). The current study used event-related functional magnetic resonance imaging to examine the neural correlates of ambiguity in a task that produced no behavioral ambiguity effect (i.e., SCT with a well-defined decision category). Twenty healthy adults participated. Results showed that despite producing no behavioral effect of ambiguity, ambiguous words were associated with the recruitment of cortical structures implicated in top-down modulation of noisy activity (e.g., left inferior frontal gyrus) when compared to unambiguous words. These results are interpreted as evidence that multiple meanings are activated for ambiguous words in SCT.
References
(2002). Semantic retrieval, mnemonic control, and prefrontal cortex. Behavioral and Cognitive Neuroscience Reviews, 1, 206–218.
(2007). Left ventrolateral prefrontal cortex and the cognitive control of memory. Neuropsychologia, 45, 2883–2901.
(2002). The English Lexicon Project: A web-based repository of descriptive and behavioral measures for 40,481 English words and nonwords. Washington University. Retrieved from elexicon.wustl.edu/ on 12 September 2007.
(1999). Attentional control of lexical processing pathways during word recognition and reading. In , Language processing (pp. 15–57). Hove, England: Psychology Press.
(2003). General multi-level linear modeling for group analysis in fMRI. NeuroImage, 20, 1052–1063.
(2005). The effects of homonomy and polysemy on lexical access: An MEG study. Cognitive Brain Research, 24, 57–65.
(2003). Neural correlates of lexical access during visual word recognition. Journal of Cognitive Neuroscience, 15, 372–393.
(2002). Detection versus estimation in event-related fMRI: Choosing the optimal stimulus timing. Neuroimage, 15, 252–264.
(1996). Semantic ambiguity effects on word identification. Journal of Experimental Psychology: Learning, Memory, and Cognition, 22, 63–85.
(2002). Challenging the widespread assumption that connectionism and distributed representations go hand-in-hand. Cognitive Psychology, 45, 413–445.
(2004). Neural systems for word meaning modulated by semantic ambiguity. NeuroImage, 22, 1128–1133.
(1993). PsyScope: An interactive graphic system for designing and controlling experiments in the psychology laboratory using Macintosh computers. Behavior Research Methods, Instruments, & Computers, 25, 257–271.
(2007). Neural correlates of semantic priming for ambiguous words: An event-related fMRI study. Brain Research, 1131, 163–172.
(2003). Temporal lobe regions engaged during normal speech comprehension. Brain, 126, 1193–1201.
(2008). NoA’s ark: Influence of the number of associates in visual word recognition. Psychonomic Bulletin & Review, 15, 1072–1077.
(1995). Improved assessment of significant activation in functional magnetic resonance imaging (fMRI): Use of a cluster-size threshold. Magnetic Resonance Medicine, 33, 636–647.
(2002). Beyond phrenology: What can neuroimaging tell us about distributed circuitry?. Annual Review of Neuroscience, 25, 221–250.
(1980). Meaning-dependent ratings of imagery, age of acquisition, familiarity, and concreteness for 387 ambiguous words. Behaviour Research Methods & Instrumentation, 12, 428–450.
(2006). Dissociation of automatic and strategic lexical-semantics: Functional magnetic resonance imaging evidence for differing roles of multiple frontotemporal regions. The Journal of Neuroscience, 26, 6523–6532.
(2001). Cross-modal repetition priming of heterographic homophones. Memory & Cognition, 29, 53–61.
(2009). Shared features dominate semantic richness effects for concrete concepts. Journal of Memory & Language, 60, 1–19.
(2005). Dissociations among tasks involving inhibition: A single-case study. Cognitive, Affective, & Behavioral Neuroscience, 5, 1–13.
(2004). Automatic semantic activation is no myth; Semantic context effects on the N400 in the letter-search task in the absence of response time effects. Psychological Science, 15, 852–857.
(1996). Effects of polysemy in lexical decision and naming: An alternative to lexical access accounts. Journal of Experimental Psychology: Human Perception and Performance, 22, 1331–1356.
(2006). Ambiguity and relatedness effects in semantic tasks: Are they due to semantic coding?. Journal of Memory and Language, 55, 247–273.
(1975). Multiple word meanings and lexical search speed. Journal of Verbal Learning & Verbal Behavior, 12, 534–537.
(2002). Improved optimization for the robust and accurate linear registration and motion correction of brain images. NeuroImage, 17, 825–841.
(2001). A global optimization method for robust affine registration of brain images. Medical Image Analysis, 5, 143–156.
(1998). Inhibition in verbal working memory revealed by brain activation. Proceedings of the National Academy of Science, 95, 8410–8413.
(2007). Disambiguating the ambiguity advantage effect in word recognition: An advantage for polysemous but not homonymous words. Journal of Neurolinguistics, 20, 1–24.
(2003). Semantic neighborhood effects on the recognition of ambiguous words. Memory & Cognition, 31, 505–515.
(2007). Lexical ambiguity in sentence comprehension. Brain Research, 1146, 115–127.
(1995). Unsettling questions about semantic ambiguity in connectionist models: Comment on Joordens and Besner (1994). Journal of Experimental Psychology: Learning, Memory, and Cognition, 21, 509–514.
(2009). The effect of aging on the inhibitory function in middle-aged subjects: A functional MRI study coupled with a color-matched Stroop task. International Journal of Geriatric Psychiatry, 24, 1062–1071.
(1993). Respects for similarity. Psychological Review, 100, 99–130.
(2002). Attention control in the aging brain: Insights from an fMRI study of the Stroop task. Brain and Cognition, 49, 277–296.
(2003). Linguistic theory and neuroimaging evidence: An fMRI study of Broca’s area in lexical semantics. Neuropsychologia, 41, 1199–1207.
(2004). The big book of concepts. MA: Cambridge.
(1998). The University of South Florida word association, rhyme, and word fragment norms. Retrieved from www.usf.edu/FreeAssociation/.
(2007a). Neural correlates of concreteness in semantic categorization. Journal of Cognitive Neuroscience, 19(8), 1407–1419.
(2007b). The neural consequences of semantic richness: When more comes to mind, less activation is observed. Psychological Science, 18, 401–406.
(2008). There are many ways to be rich: Effects of three measures of semantic richness on word recognition. Psychonomic Bulletin and Review, 15(1), 161–167.
(2004). Semantic ambiguity and the process of generating meaning from print. Journal of Experimental Psychology: Learning, Memory, and Cognition, 30, 1252–1270.
(2003). Number of features effects and semantic processing. Memory & Cognition, 31, 842–855.
(1999). The impact of semantic ambiguity on visual word recognition: Do homophone and polysemy effects co-occur?. Canadian Journal of Experimental Psychology, 53, 323–334.
(2002). The impact of feedback semantics in visual word recognition: Number-of-features effects in lexical decision and naming tasks. Psychonomic Bulletin and Review, 9, 542–549.
(2000). Turning an advantage into a disadvantage: Ambiguity effects in lexical decision versus reading tasks. Memory & Cognition, 28, 139–156.
(2004). What can neuroimaging tell us about the mind? Insights from prefrontal cortex. Current Directions in Psychological Science, 13, 177–181.
(2008). Examining a supramodal network for conflict processing: A systematic review and novel functional magnetic resonance imaging data for related visual and auditory Stroop tasks. Journal of Cognitive Neuroscience, 20, 1063–1078.
(2005). The neural mechanisms of speech comprehension: fMRI studies of semantic ambiguity. Cerebral Cortex, 15, 1261–1269.
(2002). Making sense of semantic ambiguity: Semantic competition in lexical access. Journal of Memory and Language, 46, 245–266.
(2004). Modeling the effects of semantic ambiguity in word recognition. Cognitive Science, 28, 89–104.
(2007). Multiple meanings are not necessarily a disadvantage in semantic processing: Evidence from homophone effects in semantic categorisation. Language and Cognitive Processes, 22, 453–467.
(2002). Fast robust automated brain extraction. Human Brain Mapping, 17, 143–155.
(2007). Prefrontal cortical responses to conflict during semantic and phonological tasks. Journal of Cognitive Neuroimaging, 19, 761–775.
(1988). Co-planar stereotaxic atlas of the human brain. New York: Thieme.
(2003). Neuroimaging studies of semantic memory: Inferring “how” from “where”. Neuropsychologia, 41, 280–292.
(1997). Role of left inferior prefrontal cortex in retrieval of semantic knowledge: A reevaluation. Proceedings of the National Academy of Science, 94, 14792–14797.
(2001). Recovering meaning: Left prefrontal cortex guides controlled semantic retrieval. Neuron, 31, 329–338.
(2006). Functional neuroimaging of language. In , Handbook of functional neuroimaging of cognition (pp. 191–227) (2nd ed.). London, England: The MIT Press.
(2004). Multi-level linear modeling for fMRI group analysis using Bayesian inference. NeuroImage, 21, 1732–1747.
(2001). Temporal autocorrelation in univariate linear modeling of fMRI data. NeuroImage, 14, 1370–1386.
(1995). The educator’s word frequency guide. Brewster, NJ: Touchstone Applied Science Associates.
(2007). Semantic ambiguity processing in sentence context: Evidence from event-related fMRI. NeuroImage, 34, 1270–1279.
(2004). Is left inferior frontal gyrus a general mechanism for selection?. NeuroImage, 23, 596–603.
