Six-month-old infants' preference for lexical words

Previous work has shown that newborn infants categorically discriminate the fundamental syntactic category distinction between lexical and grammatical words. In this article, we show that by the age of 6 months, infants prefer to listen to lexical over grammatical words. In Experiment 1, infants were habituated to a list of either lexical or grammatical words, and then tested on new lists of words from the same and the contrasting categories. The infants showed recovery to lexical words after habituation to grammatical words but not vice versa. This asymmetry indicates a possible preference for lexical words. In Experiments 2 and 3, preference was assessed directly by presenting infants with alternating trials of lexical and grammatical words, in the central-fixation preference procedure. The infants looked significantly longer during lexical-word than grammatical-word trials. These results show that by 6 months, infants attend preferentially to lexical words. The implications of this emerging attentional preference for subsequent language acquisition are discussed.     

Depression reduces perceptual sensitivity for positive words and pictures

There is evidence of maladaptive attentional biases for lexical information (e.g., Atchley, Ilardi, & Enloe, 2003; Atchley, Stringer, Mathias, Ilardi, & Minatrea, 2007) and for pictographic stimuli (e.g., Gotlib, Krasnoperova, Yue, & Joormann, 2004) among patients with depression. The current research looks for depressotypic processing biases among depressed out-patients and non-clinical controls, using both verbal and pictorial stimuli. A d′ measure (sensitivity index) was used to examine each participant's perceptual sensitivity threshold. Never-depressed controls evidenced a detection bias for positive picture stimuli, while depressed participants had no such bias. With verbal stimuli, depressed individuals showed specific decrements in the detection of positive person-referent words (WINNER), but not with positive non-person-referent words (SUNSHINE) or with negative words. Never-depressed participants showed no such differences across word types. In the current study, depression is characterised both by an absence of the normal positivistic biases seen in individuals without mood disorders (consistent with McCabe & Gotlib, 1995), and by a specific reduction in sensitivity for person-referent positive information that might be inconsistent with depressotypic self-schemas.     

Orthographic cues to lexical stress: Effects on naming and lexical decision

Words whose spellings represent regular phonemic patterns, such asmint, show advantages in naming and lexical decision tasks over words, such aspint, that have exceptional relations between orthographic and phonemic patterns. We have extended such phenomena to the domain of lexical stress, by showing that disyllabic words whose spellings are consistent with their stress are easier to process than words whose spellings are misleading about stress. Such words are named more quickly and are pronounced with incorrect stress less often (Experiment 1). They are also classified more quickly and accurately in lexical decision tasks (Experiments 2 and 3). These results indicate that literate speakers have learned orthographic correlates to lexical stress in English. In addition, the similarities between results in the phonemic and prosodic domains indicate that models of reading developed for the former could be extended to the latter area.     

Hemispheric sensitivity to grammatical cues: evidence for bilateral processing of number agreement in noun phrases

The present experiment employed a grammatical priming task to explore the possible contributions of the left and right cerebral hemispheres to the processing of grammatical agreement. Stimuli were three-word noun phrases, with the prime centered above the fixation point and the target presented laterally to one visual field after a 600-ms stimulus onset asynchrony. Number agreement between primes and targets was varied such that the article of the prime could be consistent (i.e., each narrow shoe or all narrow shoes), inconsistent (i.e., all narrow shoe or each narrow shoes) or neutral (i.e., the narrow shoe(s)) with respect to the inflection of the target. Half of the subjects provided lexical decision responses and the other half pronunciation. The bilateral priming effect, obtained only in lexical decision, suggests that both the left and the right hemispheres are sensitive to certain grammatical cues. In addition to the task difference in priming, the inclusion of a neutral condition and of pseudo-inflected nonwords allowed these effects to be attributed to postlexical mechanisms.     

A comparison of infants' and adults' sensitivity to western musical structure.

Adults (n = 28) and 8-month-old infants (n = 48) listened to repeated transpositions of a 10-note melody exemplifying the rules of Western tonal music. They were tested for their detection of two types of changes to that melody: (a) a 4-semitone change in 1 note that remained within the key and implied dominant harmony (diatonic change) or (b) a 1-semitone change in the same note that went outside the key (nondiatonic change). Adults easily detected the nondiatonic change but had difficulty with the diatonic change. Infants detected both changes equally well, performing better than adults in some circumstances. These findings imply that there are qualitative differences in infants' and adults' processing of musical information.     

Facilitative and inhibitory effects of location and frequency cues: evidence of a modulation in perceptual sensitivity.

The possibility that facilitative and inhibitory effects of auditory cues result because of a modulation in perceptual sensitivity was examined. Listeners were presented with a cue followed by a target, with the time period between the two varied at stimulus onset asynchronies (SOAs) of 150, 450, or 750 msec. In two conditions, the cue and target were either the same or different in location or frequency. In both conditions, listeners were required to identify the rise time of the target. Whereas the cue was presented in isolation, the target was presented in a wide-band noise background such that the required discrimination was made relatively difficult. In both conditions, a facilitative effect was apparent at the 150-msec SOA and an inhibitory effect was apparent at the 750-msec SOA for both accuracy and response time measures of performance. That these results were apparent for a judgment unrelated to the manipulated cue-target relation suggests strongly that both location-based and frequency-based auditory inhibition of return result primarily because of changes in perceptual sensitivity.     

Personality and lexical decision times for evaluative words

We studied personality influences on accessibility of pleasant and unpleasant stimuli in a sample of 129 students. Self‐reports and reports by knowledgeable informants on extraversion, neuroticism, approach temperament and avoidance temperament were combined with a go/no‐go lexical decision task that included pleasant, unpleasant and neutral words, and two response modes, manual and vocal. The data were analysed using multilevel modelling. Extraversion and approach temperament predicted faster identification of pleasant words than of neutral and of unpleasant words. Vocal responses took longer than manual responses, but mode of response did not interact with the valence of the words. Copyright © 2009 John Wiley & Sons, Ltd.     

Phonotactics, neighborhood activation, and lexical access for spoken words.

Probabilistic phonotactics refers to the relative frequencies of segments and sequences of segments in spoken words. Neighborhood density refers to the number of words that are phonologically similar to a given word. Despite a positive correlation between phonotactic probability and neighborhood density, nonsense words with high probability segments and sequences are responded to more quickly than nonsense words with low probability segments and sequences, whereas real words occurring in dense similarity neighborhoods are responded to more slowly than real words occurring in sparse similarity neighborhoods. This contradiction may be resolved by hypothesizing that effects of probabilistic phonotactics have a sublexical focus and that effects of similarity neighborhood density have a lexical focus. The implications of this hypothesis for models of spoken word recognition are discussed.     

Facultative and inhibitory effects of location and frequency cues: Evidence of a modulation in perceptual sensitivity

The possibility that facilitative and inhibitory effects of auditory cues result because of a modulation in perceptual sensitivity was examined. Listeners were presented with a cue followed by a target, with the time period between the two varied at stimulus onset asynchronies (SOAs) of 150,450, or 750 msec. In two conditions, the cue and target were either the same or different in location or frequency. In both conditions, listeners were required to identify the rise time of the target. Whereas the cue was presented in isolation, the target was presented in a wide-band noise background such that the required discrimination was made relatively difficult. In both conditions, a facilitative effect was apparent at the 150-msec SOA and an inhibitory effect was apparent at the 750-msec SOA for both accuracy and response time measures of performance. That these results were apparent for a judgment unrelated to the manipulated cue-target relation suggests strongly that both location-based and frequency-based auditory inhibition of return result primarily because of changes in perceptual sensitivity.     

The role of subsyllabic structure in lexical access to printed words

Summary Three lexical-decision experiments investigated whether the subsyllabic structure of words is processed in the course of lexical access to printed words. Experiment 1 contrasted Italian words with same orthographic structure, but different subsyllabic structures. Latencies were shorter and error rates lower for words with a syllabic structure composed of fewer subsyllabic constituents. Experiment 2 ruled out the possibility that the results of Experiment 1 were due to differences in the frequency of bigrams composing the items. Bigram frequency had no effect on words of the same frequency as that of words in Experiment 1. Finally, Experiment 3 showed that it is not the number of subsyllabic constituents that affects lexical decision — rather the internal composition and frequency of the subsyllabic structure underlying a word. These results suggest that the subsyllabic structure of words is represented in abstract form in the mental lexicon and processed during lexical access. Subsyllabic structures, which are simpler and more common in the language, are more easily activated and processed, regardless of the number of subsyllabic constituents and the number of syllables composing the word.     

Verbal comprehension: The lexical decomposition strategy to define unfamiliar words

Two experiments were conducted to study one facet of verbal intelligence—the ability of adolescents and adults to use a lexical decomposition strategy to define prefixed words and pseudowords. In the first experiment, subjects in grades 8, 10, 11, and college were given a multiple-choice vocabulary test. The test measured subjects' abilities to use wordpart meanings when defining words. Subjects' metacognitive knowledge of both the words and their prefixes and stems was assessed through a pair of rating tasks. Adults performed better than the adolescents on the vocabulary test. Evidence for a lexical decomposition strategy was found for both the adolescents and adults on subsets of the most familiar items. Measures of metacognitive knowledge were related significantly to measures of vocabulary performance for the adolescents and adults.In the second experiment, college subjects were given one of four multiple-choice vocabulary tests that included decomposable (prefixed) and nondecomposable known (words) and unknown (pseudowords) stimuli. Evidence for use of the lexical decomposition strategy was strong even though there were small effects of two performance factors predicted to affect the use of the strategy. Results are discussed in relation to a theory on the use of internal context in verbal comprehension     

The perceptual span and peripheral cues in reading

Skilled readers read passages that were displayed on a Cathode Ray Tube controlled by a computer. The readers' eye movements were monitored and certain critical words were changed by the computer as the eye was in motion. The experimental technique utilized in the study provided data on how wide the area is from which a reader acquires information during a fixation in silent reading. The results also delineate different types of visual information that are acquired from various areas within the perceptual span. It was found that a reader was able to make a semantic interpretation of a word that began 1–6 character spaces from his fixation point. When he fixated 7–12 character spaces prior to a word, he was able to pick up such gross visual characteristics as word shape and initial and final letters. It was concluded that the skilled reader is able to take advantage of information in the periphery. However, the size of the area from which he does is rather small.     

Emotion words and categories: evidence from lexical decision

We examined the categorical nature of emotion word recognition. Positive, negative, and neutral words were presented in lexical decision tasks. Word frequency was additionally manipulated. In Experiment 1, “positive” and “negative” categories of words were implicitly indicated by the blocked design employed. A significant emotion–frequency interaction was obtained, replicating past research. While positive words consistently elicited faster responses than neutral words, only low frequency negative words demonstrated a similar advantage. In Experiments 2a and 2b, explicit categories (“positive,” “negative,” and “household” items) were specified to participants. Positive words again elicited faster responses than did neutral words. Responses to negative words, however, were no different than those to neutral words, regardless of their frequency. The overall pattern of effects indicates that positive words are always facilitated, frequency plays a greater role in the recognition of negative words, and a “negative” category represents a somewhat disparate set of emotions. These results support the notion that emotion word processing may be moderated by distinct systems.     

The differential role of phonological and distributional cues in grammatical categorisation

Recognising the grammatical categories of words is a necessary skill for the acquisition of syntax and for on-line sentence processing. The syntactic and semantic context of the word contribute as cues for grammatical category assignment, but phonological cues, too, have been implicated as important sources of information. The value of phonological and distributional cues has not, with very few exceptions, been empirically assessed. This paper presents a series of analyses of phonological cues and distributional cues and their potential for distinguishing grammatical categories of words in corpus analyses. The corpus analyses indicated that phonological cues were more reliable for less frequent words, whereas distributional information was most valuable for high frequency words. We tested this prediction in an artificial language learning experiment, where the distributional and phonological cues of categories of nonsense words were varied. The results corroborated the corpus analyses. For high-frequency nonwords, distributional information was more useful, whereas for low-frequency words there was more reliance on phonological cues. The results indicate that phonological and distributional cues contribute differentially towards grammatical categorisation.     

Type and number of violations and the grammatical congruency effect in lexical decision

Summary An experiment was conducted in the Serbo-Croatian language in which native speakers/readers made lexical decisions on inflected nouns and legally inflected pseudonouns following inflected possessive pronouns. A possessive pronoun and the noun or pseudonoun that followed it could agree in case, gender, and number (0 violations), disagree in either case or gender or number (1 violation) or disagree simultaneously on two of the three (2 violations). A grammatical congruency effect was observed for both nouns and pseudonouns. Acceptance latencies were shorter and rejection latencies were longer for inflectional agreement than inflectional disagreement. However, for neither nouns nor pseudonouns was the magnitude of the effect influenced by the type or number of violations. The results are discussed in terms of (1) the automaticity of syntactic processes and (2) the properties of a decision making device (specially tailored to rapid lexical evaluations) relative to the properties of the language processor.This research was supported in part by NICHD Grants HD-08495 and HD-01994 to the University of Belgrade and Haskins Laboratories, respectively     

Extending the simultaneous-sequential paradigm to measure perceptual capacity for features and words

In perception, divided attention refers to conditions in which multiple stimuli are relevant to an observer. To measure the effect of divided attention in terms of perceptual capacity, we introduce an extension of the simultaneous-sequential paradigm. The extension makes predictions for fixed-capacity models as well as for unlimited-capacity models. We apply this paradigm to two example tasks, contrast discrimination and word categorization, and find dramatically different effects of divided attention. Contrast discrimination has unlimited capacity, consistent with independent, parallel processing. Word categorization has a nearly fixed capacity, consistent with either serial processing or fixed-capacity, parallel processing. We argue that these measures of perceptual capacity rely on relatively few assumptions compared to most alternative measures.     

Hemispheric asymmetry in lexical decisions: the effects of grammatical class and imageability

It has been suggested that neural systems for lexical processing of nouns and verbs are anatomically distinct. The aim of the present study was to investigate if brain asymmetry for the processing of these two grammatical classes is also different. Neurologically intact adults performed a lateralized lexical decision task with grammatically unambiguous words of high, medium, and low degrees of imagery. For error scores a right visual field (RVF) advantage and an overall effect of imageability were obtained. For latency scores grammatical class and imageability modified visual field differences: in the noun class a RVF advantage was obtained only for low imagery nouns, while for the verbs the RVF advantage was present for both medium and low imagery verbs. These results suggest that the participation of right hemisphere neural systems in the processing of verbs is more limited than in the processing of nouns.     

Dogs learn to solve the support problem based on perceptual cues

Numerous recent studies have investigated how animals solve means-end tasks and unraveled considerable variation in strategies used by different species. Domestic dogs (Canis familiaris) have typically performed comparably poorly in physical cognition tasks, but a recent study showed that they can solve the on–off condition of the support problem, where they are confronted with two boards, one with a reward placed on it and the other with a reward placed next to it. To explore which strategies dogs use to solve this task, we first tested 37 dogs with the on–off condition tested previously and then tested subjects that passed this condition with three transfer tasks. For the contact condition, the inaccessible reward was touching the second board. For the perceptual containment condition, the inaccessible reward was surrounded on three sides by the second board, but not supported by it, whereas for the gap condition, discontinuous boards were used. Unlike in the previous study, our subjects did not perform above chance level in the initial trials of the on–off condition, but 13 subjects learned to solve it. Their performance in the transfer tasks suggests that dogs can learn to solve the support problem based on perceptual cues, that they can quickly adopt new cues when old ones become unreliable, but also that some apparently inherent preferences are hard to overcome. Our study contributes to accumulating evidence demonstrating that animals typically rely on a variety of perceptual cues to solve physical cognition tasks, without developing an understanding of the underlying causal structure.