Phonological perception by birds: budgerigars can perceive lexical stress

Metrical phonology is the perceptual “strength” in language of some syllables relative to others. The ability to perceive lexical stress is important, as it can help a listener segment speech and distinguish the meaning of words and sentences. Despite this importance, there has been little comparative work on the perception of lexical stress across species. We used a go/no-go operant paradigm to train human participants and budgerigars (Melopsittacus undulatus) to distinguish trochaic (stress-initial) from iambic (stress-final) two-syllable nonsense words. Once participants learned the task, we presented both novel nonsense words, and familiar nonsense words that had certain cues removed (e.g., pitch, duration, loudness, or vowel quality) to determine which cues were most important in stress perception. Members of both species learned the task and were then able to generalize to novel exemplars, showing categorical learning rather than rote memorization. Tests using reduced stimuli showed that humans could identify stress patterns with amplitude and pitch alone, but not with only duration or vowel quality. Budgerigars required more than one cue to be present and had trouble if vowel quality or amplitude were missing as cues. The results suggest that stress patterns in human speech can be decoded by other species. Further comparative stress-perception research with more species could help to determine what species characteristics predict this ability. In addition, tests with a variety of stimuli could help to determine how much this ability depends on general pattern learning processes versus vocalization-specific cues.     

Stress and context in auditory word recognition

Recent work in psycholinguistics has revealed that the role of lexical stress in auditory word recognition may be a complex one involving other potential sources of information. In the present investigation, the nature of lexical stress effects on auditory word recognition in context is examined. The ability of subjects to identify words based on the prosodic pattern of the word is examined for the words in isolation and in a sentence context. The results revealed a small influence of stress on the identification of the stimulus waveforms relative to a large effect of context. The data indicate that lexical stress is used in the identification of the words; however, its role is minor compared to the importance of contextual information.This article is based on sections of a doctoral dissertation presented to Indiana University, Bloomington, Indiana. This research was supported in part by NIH research grant NS-12179-08 to Indiana University and a Graduate Student Grant-in-Aid of Research from Indiana University.     

Recognition memory for foreign language lexical stress

This study investigated whether English speakers retained the lexical stress patterns of newly learned Spanish words. Participants studied spoken Spanish words (e.g., DUcha [shower], ciuDAD [city]; stressed syllables in capital letters) and subsequently performed a recognition task, in which studied words were presented with the same lexical stress pattern (DUcha) or the opposite lexical stress pattern (CIUdad). Participants were able to discriminate same- from opposite-stress words, indicating that lexical stress was encoded and used in the recognition process. Word-form similarity to English also influenced outcomes, with Spanish cognate words and words with trochaic stress (MANgo) being recognized more often and more quickly than Spanish cognate words with iambic stress (soLAR) and noncognates. The results suggest that while segmental and suprasegmental features of the native language influence foreign word recognition, foreign lexical stress patterns are encoded and not discarded in memory.     

Sticky thoughts: depression and rumination are associated with difficulties manipulating emotional material in working memory

Cognitive inflexibility may play an important role in rumination, a risk factor for the onset and maintenance of depressive episodes. In the study reported here, we assessed participants' ability to either reverse or maintain in working memory the order of three emotion or three neutral words. Differences (or sorting costs) between response latencies in backward trials, on which participants were asked to reverse the order of the words, and forward trials, on which participants were asked to remember the words in the order in which they were presented, were calculated. Compared with control participants, depressed participants had higher sorting costs, particularly when presented with negative words. It is important to note that rumination predicted sorting costs for negative words but not for positive or neutral words in the depressed group. These findings indicate that depression and rumination are associated with deficits in cognitive control.     

At 11 months,prosody still outranks statistics

English‐learning 7.5‐month‐olds are heavily biased to perceive stressed syllables as word onsets. By 11 months, however, infants begin segmenting non‐initially stressed words from speech. Using the same artificial language methodology as Johnson and Jusczyk (2001 ), we explored the possibility that the emergence of this ability is linked to a decreased reliance on prosodic cues to word boundaries accompanied by an increased reliance on syllable distribution cues. In a baseline study, where only statistical cues to word boundaries were present, infants exhibited a familiarity preference for statistical words. When conflicting stress cues were added to the speech stream, infants exhibited a familiarity preference for stress as opposed to statistical words. This was interpreted as evidence that 11‐month‐olds weight stress cues to word boundaries more heavily than statistical cues. Experiment 2 further investigated these results with a language containing convergent cues to word boundaries. The results of Experiment 2 were not conclusive. A third experiment using new stimuli and a different experimental design supported the conclusion that 11‐month‐olds rely more heavily on prosodic than statistical cues to word boundaries. We conclude that the emergence of the ability to segment non‐initially stressed words from speech is not likely to be tied to an increased reliance on syllable distribution cues relative to stress cues, but instead may emerge due to an increased reliance on and integration of a broad array of segmentation cues.     

Cross-language word segmentation by 9-month-olds

Dutch-learning and English-learning 9-month-olds were tested, using the Headturn Preference Procedure, for their ability to segment Dutch words with strong/weak stress patterns from fluent Dutch speech. This prosodic pattern is highly typical for words of both languages. The infants were familiarized with pairs of words and then tested on four passages, two that included the familiarized words and two that did not. Both the Dutch- and the English-learning infants gave evidence of segmenting the targets from the passages, to an equivalent degree. Thus, English-learning infants are able to extract words from fluent speech in a language that is phonetically different from English. We discuss the possibility that this cross-language segmentation ability is aided by the similarity of the typical rhythmic structure of Dutch and English words.     

Bilingual frequency encoding

Two experiments are reported that examine the nature of the processing of frequency information in Spanish-English bilinguals. In the first study, subjects studied a list of English-only, Spanish-only, and mixed-language words varying in their frequency of occurrence, and under conditions of being either informed or uninformed about the later frequency test. Subjects were then shown pictures represeting the nominally presented items and had to give frequency judgments for the words depicting the objects. Frequency judgments were significantly faster when the words had been presented in a single language, suggesting a summation of access times for the mixed-language words. Instructional conditions had no effect on frequency judgments, but the latency to judge was significantly reduced for the informed subjects. In the second study, using similar acquisition procedures, subjects were shown test words in either the same or the different language from the one in which the words were originally experienced. Subjects demonstrated a clear ability to assign frequencies according to the relationship between acquisition and test language. The data were discussed in terms of supporting the hypothesis of separate bilingual language processing, and implications for the automatic nature of frequency acquisition were also addressed.This article is based on a paper originally presented at the meetings of the Southwestern Psychological Association, San Antonio, April 1983.     

Auditory recognition without identification

When visual recognition test items are unidentifiable--through fragmentation, for example--participants can discriminate between unidentifiable items that were presented recently and those that were not. The present study extends this recognition without identification phenomenon to the auditory modality. In several experiments, participants listened to words and were then presented with spoken recognition test items that were embedded in white noise. Participants attempted to identify each spoken word through the white noise, then rated the likelihood that the word was studied. Auditory recognition without identification was found: Participants discriminated between studied and unstudied words in the absence of an ability to identify them through white noise, even when the voice changed from male to female and when the study list was presented visually. The effect was also found when identification was hindered through the isolation of particular phonemes, suggesting that phoneme information may be present in memory traces for recently spoken words.     

Newborn infants' sensitivity to perceptual cues to lexical and grammatical words.

In our study newborn infants were presented with lists of lexical and grammatical words prepared from natural maternal speech. The results show that newborns are able to categorically discriminate these sets of words based on a constellation of perceptual cues that distinguish them. This general ability to detect and categorically discriminate sets of words on the basis of multiple acoustic and phonological cues may provide a perceptual base that can help older infants bootstrap into the acquisition of grammatical categories and syntactic structure.     

Mapping novel labels to actions: how the rhythm of words guides infants' learning

We investigated the effect of lexical stress on 16-month-olds' ability to form associations between labels and paths of motion. Disyllabic English nouns tend to have a strong-weak (trochaic) stress pattern, and verbs tend to have a weak-strong (iambic) pattern. We explored whether infants would use word stress information to guide word-action associations during learning. Infants heard two novel words with either verb-like iambic stress or noun-like trochaic stress. Each word was paired with a single novel object performing one of two path actions and was tested using path-switch trials. Only infants in the iambic stress condition learned the association between the novel words and the path actions. To further investigate infants' difficulty in mapping the trochaic labels to the actions, we conducted an additional study in which infants were given an object switch task using the trochaic labels. In this case, infants were able to associate the trochaic labels with the objects, providing further support that infants use lexical stress to guide label-referent associations. This study demonstrates that by 16months, English-learning infants have developed a bias to expect disyllabic action labels to have iambic stress patterns, consistent with native language stress patterns.     

How infants begin to extract words from speech

A crucial step for acquiring a native language vocabulary is the ability to segment words from fluent speech. English-learning infants first display some ability to segment words at about 7.5 months of age. However, their initial attempts at segmenting words only approximate those of fluent speakers of the language. In particular, 7.5-month-old infants are able to segment words that conform to the predominant stress pattern of English words. The ability to segment words with other stress patterns appears to require the use of other sources of information about word boundaries. By 10.5 months, English learners display sensitivity to additional cues to word boundaries such as statistical regularities, allophonic cues and phonotactic patterns. Infants’ word segmentation abilities undergo further development during their second year when they begin to link sound patterns with particular meanings. By 24 months, the speed and accuracy with which infants recognize words in fluent speech is similar to that of native adult listeners. This review describes how infants use multiple sources of information to locate word boundaries in fluent speech, thereby laying the foundations for language understanding.     

Effects of pre-learning stress on memory for neutral, positive and negative words: Different roles of cortisol and autonomic arousal

Stress can have enhancing or impairing effects on memory. Here, we addressed the effect of pre-learning stress on subsequent memory and asked whether neutral and emotionally valent information are differentially affected by specific stress components, autonomic arousal and stress-induced cortisol. Ninety-six healthy men and women underwent either a stressor (modified cold pressor test) or a control warm water exposure. During stress, participants showed comparable autonomic arousal (heart rate, blood pressure), while 60 percent showed an increase of cortisol (responders vs. 40 percent non-responders). Ten minutes after the cold pressor test neutral, positive and negative words were presented. Free recall was tested 1 and 24 h later. Overall, positive and negative words were better recalled than neutral words. Stress enhanced the recall of neutral words independently of cortisol response. In contrast, the free recall of negative words was enhanced in cortisol responders in the 1-h but not 24-h test which might suggest different effects of cortisol on consolidation and reconsolidation processes. Recall for positive words was unaffected by stress-induced cortisol. To summarize, (i) pre-learning stress can enhance memory for neutral words independently of cortisol and (ii) stress effects on memory for negative words appear to rely on stress-induced cortisol elevations, the absence of this effect for positive words might be at least partly due to differences in arousal evoked by positive vs. negative words.     

Recall failure following successful generation and recognition of responses by alcoholic Korsakoff patients

Amnesic Korsakoff patients and controls were presented with twelve words, each shown individually in the presence of a weak associate. They were then asked to freely associate to 12 other words that were strong associates of the to-be-remembered (TBR) words. The Korsakoff patients generated, and were able to recognize, as many of the TBR words as the controls. Yet, in spite of this recognition ability, these same patients were subsequently unable to recall the critical TBR words when the weak cues were again presented. A follow-up study found that the same recognition results could be obtained with Korsakoffs months after initial presentation suggesting that the patients might initially have “recognized” the most highly associated words simply because they represented the most probable choices. Intermediate association prompts failed to generate correct responses. It was hypothesized that the Korsakoff patients cannot restructure their semantic associative hierarchy during input in such a way as to become sensitized to other than the strongest associates as prompts during recall.     

Girls Not Boys Show Gender-Connotation Encoding from Print

The present study examines gender differences in children's encoding of gender-connotation from words. The release from proactive interference method was used to measure gender-connotation encoding. Forty-eight third-grade children attending a public elementary school serving a predominantly White middle-socioeconomic-status community participated and were presented with stimulus words in print. The design of the study can be characterized as a two (gender) by two (condition: control vs. experimental) by four (trials) factorial. Results revealed reliable proactive interference buildup and release for gender-connotation for girls, but not for boys. This new finding, taken together with extant research, demonstrates that while both boys and girls have the ability to encode gender-connotation from aurally presented words, the spontaneous activation of gender-connotation attributes with print is not guaranteed for boys.     

Is early word-form processing stress-full? How natural variability supports recognition

In a series of studies, we examined how mothers naturally stress words across multiple mentions in speech to their infants and how this marking influences infants’ recognition of words in fluent speech. We first collected samples of mothers’ infant-directed speech using a technique that induced multiple repetitions of target words. Acoustic analyses revealed that mothers systematically alternated between emphatic and nonemphatic stress when talking to their infants. Using the headturn preference procedure, we then tested 7.5-month-old infants on their ability to detect familiarized bisyllabic words in fluent speech. Stress of target words (emphatic and nonemphatic) was systematically varied across familiarization and recognition phases of four experiments. Results indicated that, although infants generally prefer listening to words produced with emphatic stress, recognition was enhanced when the degree of emphatic stress at familiarization matched the degree of emphatic stress at recognition.     

Task demands and age‐related differences in retrieval and response inhibition

This study investigates the role of task demands on children's ability to inhibit irrelevant information using a block‐cued directed‐forgetting task. Recall performance was compared in a block‐cued directed‐forgetting task in which task demands had been decreased by presenting blocks of semantically related words with that in which unrelated words were presented. Inhibition patterns of recall were found at a younger age in the task that contained the related words than in the task that contained the unrelated words. These results suggest that previous results charting the development of cognitive inhibition may not have been exclusively the product of the development of inhibition, but rather a product of both the difficulty of the task and the development of inhibition.     

LEX I and II: Two databases of surface word forms for psycholinguistic research in Spanish

Two databases of Spanish surface word forms are presented. Surface word forms are words considered as orthographically or phonologically specified without reference to their meaning or syntactic category. The databases are based on the productive written vocabulary of children between the ages of 6 and 10 years. Statistical and structural information is presented concerning surface word-form frequency, consonant-vowel (CV) structure, number of syllables, syllables, syllable CV structure, and subsyllabic units. LEX I was intended to aid in the study of reading processes. Entries were orthographic surface word forms; words were divided in their components following orthographic criteria. LEX II was designed for spoken language research. Accordingly, words were transcribed phonologically and phonological criteria were applied in extracting the internal units. Information about stress location was also provided. Together, LEX I and LEX II represent a useful tool for psycholinguists interested in the study of people acquiring Spanish as a first or foreign language and of Spanish-speaking populations in general.     

The beginnings of word segmentation in english-learning infants

A series of 15 experiments was conducted to explore English-learning infants' capacities to segment bisyllabic words from fluent speech. The studies in Part I focused on 7.5 month olds' abilities to segment words with strong/weak stress patterns from fluent speech. The infants demonstrated an ability to detect strong/weak target words in sentential contexts. Moreover, the findings indicated that the infants were responding to the whole words and not to just their strong syllables. In Part II, a parallel series of studies was conducted examining 7.5 month olds' abilities to segment words with weak/strong stress patterns. In contrast with the results for strong/weak words, 7.5 month olds appeared to missegment weak/strong words. They demonstrated a tendency to treat strong syllables as markers of word onsets. In addition, when weak/strong words co-occurred with a particular following weak syllable (e.g., "guitar is"), 7.5 month olds appeared to misperceive these as strong/weak words (e.g., "taris"). The studies in Part III examined the abilities of 10.5 month olds to segment weak/strong words from fluent speech. These older infants were able to segment weak/strong words correctly from the various contexts in which they appeared. Overall, the findings suggest that English learners may rely heavily on stress cues when they begin to segment words from fluent speech. However, within a few months time, infants learn to integrate multiple sources of information about the likely boundaries of words in fluent speech.     

嗓音源判断过程中的范畴效应和通道效应

该项研究通过设计4种实验条件,旨在探讨不同嗓音词的再认和嗓音判断过程各自的特点及其相互联系。4种实验条件是由2种诵读方式和2种测试方式组合而成,2种诵读方式为同范畴同嗓音和同范畴异嗓音,2种测试方式为视觉呈现和听觉呈现。52名大学生被试随机分成4个独立的组,分别接受一种实验处理。实验结果显示：(1)同范畴同嗓音条件与同范畴异嗓音条件相比,前者项目词的嗓音源判断效果好。提示增加相同记忆源项目间语义联系将有利于记忆源的检测判断。(2)项目再认与项目嗓音判断结果不完全一致,只有在诵读方式为同范畴同嗓音测试方式为听觉呈现情境下,两者有较高的正相关。(3)在同范畴同嗓音诵读条件下,再认反映出学习和测试通道源一致性优势效应,嗓音判断没有反映出通道源一致性优势效应。