Time course of frequency effects in spoken-word recognition: evidence from eye movements

In two experiments, eye movements were monitored as participants followed spoken instructions to click on and move pictures with a computer mouse. In Experiment 1, a referent picture (e.g., the picture of a bench) was presented along with three pictures, two of which had names that shared the same initial phonemes as the name of the referent (e.g., bed and bell). Participants were more likely to fixate the picture with the higher frequency name (bed) than the picture with the lower frequency name (bell). In Experiment 2, referent pictures were presented with three unrelated distractors. Fixation latencies to referents with high-frequency names were shorter than those to referents with low-frequency names. The proportion of fixations to the referents and distractors were analyzed in 33-ms time slices to provide fine-grained information about the time course of frequency effects. These analyses established that frequency affects the earliest moments of lexical access and rule out a late-acting, decision-bias locus for frequency. Simulations using models in which frequency operates on resting-activation levels, on connection strengths, and as a postactivation decision bias provided further constraints on the locus of frequency effects.     

Mapping from Sound to Meaning: Reduced Lexical Activation in Broca''s Aphasics

Recent studies of lexical access in Broca's aphasics suggest that lexical activation levels are reduced in these patients. The present study compared the performance of Broca's aphasics with that of normal subjects in an auditory semantic priming paradigm. Lexical decision times were measured in response to word targets preceded by an intact semantically related prime word ("cat"-"dog"), by a related prime in which one segment was acoustically altered to produce a poorer phonetic exemplar ("c*at"-"dog"), and by a semantically unrelated prime ("ring"-"dog"). The effects of the locus of the acoustic distortion within the prime word (initial or final position) and the presence of potential lexical competitors ("cat" --> /gaet/versus "coat" --> "goat") were examined. In normal subjects, the acoustic manipulations produce a small, short-lived reduction in semantic facilitation irrespective of the position of the distortion in the prime word or the presence of a voiced lexical competitor. In contrast, Broca's aphasics showed a large and lasting reduction in priming in response to word-initial acoustic distortions, but only a weak effect of word-final distortions on priming. In both phonetic positions, the effect of distortion was greater for prime words with a lexical competitor. These findings are compatible with the claim that Broca's aphasics have reduced lexical activation levels, which may result in a disruption of the bottom-up access of words on the basis of acoustic input as well as increased vulnerability to competition between acoustically similar lexical items.     

Probabilistic constraint satisfaction at the lexical/phonetic interface: evidence for gradient effects of within-category VOT on lexical access

Research in speech perception has been dominated by a search for invariant properties of the signal that correlate with lexical and sublexical categories. We argue that this search for invariance has led researchers to ignore the perceptual consequences of systematic variation within such categories and that sensitivity to this variation may provide an important source of information for integrating information over time in speech perception. Data from a study manipulating VOT continua in words using an eye-movement paradigm indicate that lexical access shows graded sensitivity to within-category variation in VOT and that this sensitivity has a duration sufficient to be useful for information integration. These data support a model in which the perceptual system integrates information from multiple sources and from the surrounding temporal context using probabilistic cue-weighting mechanisms.     

When words and space collide: Spatial attention interacts with lexical access during word recognition

Recent research has suggested an important role for spatial attention in reading, however the nature of this influence is unclear. Further, it has been shown that intention to engage in linguistic processing can enhance lexical processing. Therefore, we developed a novel paradigm to examine the impact of spatial attention on primed and unprimed lexical processing. In a lexical decision task, targets were preceded by a cue to lexical access and spatial location simultaneously. Results indicated that on spatially valid trials, the lexical cuing effect was large and word processing was enhanced, suggesting that spatial attention influences lexical access. On spatially invalid trials, lexical cuing effects were significantly decreased, resulting in a spatial cuing by lexical cuing interaction. Results from this experiment provide evidence that spatial attention interacts with lexical access during word processing. This novel paradigm provides a new avenue for exploring the relations between spatial attention and reading processes.     

Some linguistic determinants of Swedish word recognition

Native Swedish words and words of foreign origin were studied in a word fill-in task (Experiment 1), in a task in which words were explicitly classified as being native or loan words (Experiment 2), and in a lexical decision task in which a small onset asynchrony was introduced in displaying a word's letter pattern (Experiment 3). The findings obtained show that, both in simple printed word recognition and when asked to make explicit judgments about origin, readers are sensitive to phonological features of words not marked in Swedish orthography. It was further found that previewing a substring of word-initial letters which determines a word's root morpheme will prime recognition, whereas previewing a randomly selected pattern of letters inhibits recognition.     

An ERP study on self-relevant object recognition

We performed an event-related potential study to investigate the self-relevance effect in object recognition. Three stimulus categories were prepared: SELF (participant's own objects), FAMILIAR (disposable and public objects, defined as objects with less-self-relevant familiarity), and UNFAMILIAR (others' objects). The participants' task was to watch the stimuli passively. Results showed that left-lateralized N250 activity differentiated SELF and FAMILIAR from UNFAMILIAR, but SELF and FAMILIAR were not differentiated. In the later time-course, SELF was dissociated from FAMILIAR, indicating the self-relevance effect in object recognition at this stage. This activity did not show consistent lateralization, in contrast to previous studies reporting right lateralization in self-relevant face and name recognition. We concluded that in object recognition, self-relevance was processed by higher-order cognitive functions later than 300ms after stimulus onset.     

An ERP investigation of binding and coreference

This study examines the nature of violations in processing one class of binding construction, namely those involving reflexives and their antecedents. When arguments of verbs appear at the point where a syntactic violation is detected, a centroparietal positivity occurs, peaking at 600 ms after the presentation of the stimulus (P600), as is consistent with other types of syntactic anomalies. However, nonarguments in similar sentences fail to elicit the same response. For example, the reflexive in "John's brothers like himself" is in an argument position and elicits the P600 when compared to its grammatical counterpart. The nonargument, participating in the same type of mismatch, "John's brothers like Bill and himself," does not elicit the same positivity. This provides evidence that there are two processes involved in parsing this binding construction, one syntactic and another as yet unidentified, perhaps involving meaning or pragmatics.     

Source Monitoring: ERP Evidence for Greater Reactivity to Nontarget Information in Older Adults

Event-Related Potentials (ERPs) were collected concurrently with stimulus presentation during a source monitoring task. Younger adults were less likely than older adults to make source monitoring errors and their ERP records showed far greater discrimination between target stimuli and familiar but nontarget foils. Older adults not only made more source errors but produced high amplitude late positivities to the nontarget foils even when these foils were correctly rejected. Under divided attention conditions, younger adults performance was similar to that of the older adults both behaviorally and electrophysiologically. These data illustrate the role that attentional resources play in the ability to inhibit response tendencies and suggest that age differences in source monitoring may be more related to attentional control than inefficiencies in the encoding of contextual information. As well, they suggest that the ERP late positivity may represent a more general response to item salience rather than serve as an index of recollection as is the current view.     

Gradient effects of within-category phonetic variation on lexical access

In order to determine whether small within-category differences in voice onset time (VOT) affect lexical access, eye movements were monitored as participants indicated which of four pictures was named by spoken stimuli that varied along a 0-40 ms VOT continuum. Within-category differences in VOT resulted in gradient increases in fixations to cross-boundary lexical competitors as VOT approached the category boundary. Thus, fine-grained acoustic/phonetic differences are preserved in patterns of lexical activation for competing lexical candidates and could be used to maximize the efficiency of on-line word recognition.     

Linking sight and sound: fMRI evidence of primary auditory cortex activation during visual word recognition

We describe two studies that used repetition priming paradigms to investigate brain activity during the reading of single words. Functional magnetic resonance images were collected during a visual lexical decision task in which nonword stimuli were manipulated with regard to phonological properties and compared to genuine English words. We observed a region in left-hemisphere primary auditory cortex linked to a repetition priming effect. The priming effect activity was observed only for stimuli that sound like known words; moreover, this region was sensitive to strategic task differences. Thus, a brain region involved in the most basic aspects of auditory processing appears to be engaged in reading even when there is no environmental oral or auditory component.     

Heeding the voice of experience: the role of talker variation in lexical access

Two experiments used the head-mounted eye-tracking methodology to examine the time course of lexical activation in the face of a non-phonemic cue, talker variation. We found that lexical competition was attenuated by consistent talker differences between words that would otherwise be lexical competitors. In Experiment 1, some English cohort word-pairs were consistently spoken by a single talker (male couch, male cows), while other word-pairs were spoken by different talkers (male sheep, female sheet). After repeated instances of talker-word pairings, words from different-talker pairs showed smaller proportions of competitor fixations than words from same-talker pairs. In Experiment 2, participants learned to identify black-and-white shapes from novel labels spoken by one of two talkers. All of the 16 novel labels were VCVCV word-forms atypical of, but not phonologically illegal in, English. Again, a word was consistently spoken by one talker, and its cohort or rhyme competitor was consistently spoken either by that same talker (same-talker competitor) or the other talker (different-talker competitor). Targets with different-talker cohorts received greater fixation proportions than targets with same-talker cohorts, while the reverse was true for fixations to cohort competitors; there were fewer erroneous selections of competitor referents for different-talker competitors than same-talker competitors. Overall, these results support a view of the lexicon in which entries contain extra-phonemic information. Extensions of the artificial lexicon paradigm and developmental implications are discussed.     

The bilateral effect: callosal inhibition or intrahemispheric competition?

The magnification of visual field asymmetry observed with bilateral compared to unilateral tachistoscopic presentation of homologous stimuli (bilateral effect) can be explained by two hypothetical processes: homologous activation with subsequent inhibition of callosal information transfer or intrahemispheric competition for processing resources. A lexical decision task with unilateral and bilateral stimulation and response with the right or left hand was used in an attempt to decide between these hypotheses. Analysis of response time data revealed a bilateral effect, superimposed on a right visual field advantage, and no interaction between visual field and response hand. Results are consistent with the hypothesis of intrahemispheric competition in the left hemisphere.     

Rapid word identification in pure alexia is lexical but not semantic

Following the notion that patients with pure alexia have access to two distinct reading strategies-letter-by-letter reading and semantic reading-a training program was devised to facilitate reading via semantics in a patient with pure alexia. Training utilized brief stimulus presentations and required category judgments rather than explicit word identification. The training was successful for trained words, but generalized poorly to untrained words. Additional studies involving oral reading of nouns and of functors also resulted in improved reading of trained words. Pseudowords could not be trained to criterion. The results suggest that improved reading can be achieved in pure alexia by pairing rapidly presented words with feedback. Focusing on semantic processing is not essential to this process. It is proposed that the training strengthens connections between the output of visual processing and preexisting orthographic representations.     

Effects of sentential context on the processing of unambiguous words by the two cerebral hemispheres

The effect of sentence context on the processing of different aspects of meaning of unambiguous nouns by the two cerebral hemispheres was examined. Participants performed a lexical decision task on target words following two primes, an unambiguous noun preceded by an incomplete sentence. Priming sentences were consistent with either the dominant or the subordinate aspect of meaning of their final unambiguous word. Short and long SOAs were used. A principal finding of this study was that, when compared to unrelated aspects of meaning, for both the short and the long SOAs, the dominant and subordinate aspects of meaning of the unambiguous words were activated regardless of context in both hemispheres. However, the activation of the subordinate aspect of meaning of unambiguous words appears to be more sensitive to sentential context, especially when the unambiguous word is being processed by the left hemisphere.     

An ERP study of famous face incongruity detection in middle age

Age-related changes in famous face incongruity detection were examined in middle-aged (mean = 50.6) and young (mean = 24.8) subjects. Behavioral and ERP responses were recorded while subjects, after a presentation of a "prime face" (a famous person with the eyes masked), had to decide whether the following "test face" was completed with its authentic eyes (congruent) or with other eyes (incongruent). The principal effects of advancing age were (1) behavioral difficulties in discriminating between incongruent and congruent faces; (2) a reduced N400 effect due to N400 enhancement for both congruent and incongruent faces; (3) a latency increase of both N400 and P600 components. ERPs to primes (face encoding) were not affected by aging. These results are interpreted in terms of early signs of aging.     

Predicting dyslexia at 8 years of age using neonatal brain responses

Auditory event-related potentials recorded at birth to speech and nonspeech syllables from six scalp electrodes discriminated between newborn infants who 8 years later would be characterized as dyslexic, poor, or normal readers. These findings indicate that reading problems can be identified and possible interventions undertaken up to 9 years earlier than is currently possible.     

Studying the grammatical aspects of word recognition: lexical priming,parsing, and syntactic ambiguity resolution

Two experiments are reported examining the relationship between lexical and syntactic processing during language comprehension, combining techniques common to the on-line study of syntactic ambiguity resolution with priming techniques common to the study of lexical processing. By manipulating grammatical properties of lexical primes, we explore how lexically based knowledge is activated and guides combinatory sentence processing. Particularly, we find that nouns (like verbs, see Trueswell & Kim, 1998) can activate detailed lexically specific syntactic information and that these representations guide the resolution of relevant syntactic ambiguities pertaining to verb argument structure. These findings suggest that certain principles of knowledge representation common to theories of lexical knowledge—such as overlapping and distributed representations—also characterize grammatical knowledge. Additionally, observations from an auditory comprehension study suggest similar conclusions about the lexical nature of parsing in spoken language comprehension. They also suggest that thematic role and syntactic preferences are activated during word recognition and that both influence combinatory processing.     

Orthographic neighbors and visual word recognition

Two lexical decision experiments, using words that were selected and closely matched on several criteria associated with lexical access, provide evidence of facilitatory effects of orthographic neighborhood size and no significant evidence of inhibitory effects of orthographic neighborhood frequency on lexical access. The words used in Experiment 1 had few neighbors that were higher in frequency. In Experiment 2, the words employed had several neighbors that were higher in frequency. Both experiments showed that words possessing few neighbors evoked slower responses than those possessing many neighbors. Also, in both experiments, neighborhood size effects occurred even though words from large neighborhoods had more potentially interfering higher-frequency neighbors than words from small neighborhoods.     

The Relation of ERP Components to Complex Memory Processing

The relation between various ERP components generated during encoding of a word and its subsequent recall were investigated using a “rote” serial-order and an “elaborative” category memory task. Words (flashed separately) were time-locked to EEG recordings from 21 cortical sites. ERP components from the five subjects having the highest recall scores were compared to the five lowest scoring subjects. Results based on the P200 peak amplitude data as well as the N400 and late positive component peak amplitude and latency data suggest that anterior and posterior distributional differences are elicited during encoding of words for rote and elaborative memory tasks. Furthermore, strong individual differences in these patterns were found as a function of task. A tentative argument was made that the obtained anterior and posterior differences may index different word feature selection and encoding processes, which are differentially utilized by high and low recallers.     

Managerial Personality and Performance: A Semi-idiographic Approach

Understanding the relationship between personality and behavior requires accounting for a broad set of traits within each person and the demands of a specific role or situation. To address these requirements, we assessed the relevance or ordering of traits within an individual (an idiographic approach) and compared these orderings across individuals occupying similar organizational situations (a nomothetic approach). We illustrate the utility of this semi-idiographic approach with a longitudinal study of Masters of Business Administration (MBA) students. The MBAs whose personalities were more similar to a template of the successful young manager received more job offers upon graduating and, subsequently, earned higher salaries, were more likely to be working full-time, and had changed jobs less often than did those who fit the managerial template less well.