Development of Phonological Constancy: Toddlers' Perception of Native- and Jamaican-Accented Words

ABSTRACT— Efficient word recognition depends on detecting critical phonetic differences among similar-sounding words, or sensitivity to phonological distinctiveness , an ability evident at 19 months of age but unreliable at 14 to 15 months of age. However, little is known about phonological constancy , the equally crucial ability to recognize a word's identity across natural phonetic variations, such as those in cross-dialect pronunciation differences. We show that 15- and 19-month-old children recognize familiar words spoken in their native dialect, but that only the older children recognize familiar words in a dissimilar nonnative dialect, providing evidence for emergence of phonological constancy by 19 months. These results are compatible with a perceptual-attunement account of developmental change in early word recognition, but not with statistical-learning or phonological accounts. Thus, the complementary skills of phonological constancy and distinctiveness both appear at around 19 months of age, together providing the child with a fundamental insight that permits rapid vocabulary growth and later reading acquisition.     

Homeless women and their families: Characteristics,life circumstances,and needs

This study investigated the needs of a sample of 100 women from shelters for the homeless in Richmond, Virginia. The women's responses to a 117-item interview were used to obtain information regarding their domicilary status, work history, educational background, family and health history, social support, reasons for homelessness, and social service needs. The results indicated that a significant number of the women had moved as many as six times within the past five years for various reasons, including domestic violence, interpersonal conflict, overcrowding, and eviction. Many women were high school graduates and had job skills in the health care, educational, and clerical fields. Most women were raised by their natural or extended family and the majority of them had a friend or family member who provided social support. Identified needs included housing, food, clothing, and transportation. The needs of homeless women and their children were different from the needs of the homeless chronically mentally ill and require specialized services as well as an increase in the available number of low-income housing units.     

Disrupting the conditioned stimulus preexposure effect in flavor-aversion learning: effects of interoceptive distractor manipulations

Rats exposed to a flavor prior to a conditioning trial involving that stimulus learn a significantly diminished flavor aversion relative to nonpreexposed control animals. A series of four experiments investigated the ability of the conditioned stimulus (CS) preexposure effect to be disrupted by the introduction of a distractor flavor stimulus between the preexposure and conditioning episodes. Experiment 1 demonstrated that the preexposure effect could be reduced by a distractor presented immediately following the preexposure. In Experiment 2, it was discovered that a novel distractor was more effective than a familiar distractor, even though both stimuli were sensorily equivalent. Experiment 3 further analyzed the distractor effect and demonstrated that the magnitude of disruption was more pronounced with immediate than with delayed (3 hr) distractor manipulations. Finally, Experiment 4 assessed the effects of the distractor in the absence of CS preexposure. The relation of the results from these experiments to general information theory is discussed.     

Fimbria/fornix lesions facilitate the learning of a nonspatial response task

The spatial cognitive map theory of O’Keefe and Nadel (1978) predicts that lesions of the hippocampal system should impair learning on spatial tasks but not learning on nonspatial tasks. However, there is evidence that such lesions can facilitate learning on certain nonspatial tasks. Their theory does not predict such facilitation. Nevertheless, it is reasonable to expect that animals possessing a spatial cognitive map would have an inherent bias to engage a mapping strategy and thus be at a disadvantage on certain nonspatial tasks in comparison with animals without the mapping capacity and bias. In the present study, fimbria/fornix lesions impaired learning on a spatial task, but actually facilitated learning on a nonspatial task of equal difficulty. Thus, brain lesions that interfere with map functioning can facilitate learning on tasks for which a mapping strategy interferes with task solution. The results require a modification of the spatial cognitive map theory.     

Children and adolescents discharged from public psychiatric hospital: Evaluation of outcome in a continuum of care

Ninety children and adolescents admitted to two state-operated psychiatric hospitals were followed from the time of their admission through one year post discharge. Data were collected from the children and adolescents, their families and clinicians at three intervals (during hospitalization, three months post discharge, and one year post discharge) to identify demographic, clinical, and service history characteristics of the children and adolescents, as well as to track their placement and other dispositional status following discharge from the hospital. The data indicated that the children and adolescents were seriously emotionally and behaviorally disturbed, came from families which were economically disadvantaged, and did not typically live in two-parent families. While the majority of the children and adolescents received recommended aftercare services during the three months following discharge from the hospital, there was a decline in placement stability for the children at the one-year post discharge followup. The most important predictors of successful outcome at discharge were living with a family member at the time of hospitalization and the participation of the family in the treatment planning during hospitalization.     

Young infants' perception of liquid coarticulatory influences on following stop consonants

Phonetic segments are coarticulated in speech. Accordingly, the articulatory and acoustic properties of the speech signal during the time frame traditionally identified with a given phoneme are highly context-sensitive. For example, due to carryover coarticulation, the front tongue-tip position for /1/ results in more fronted tongue-body contact for a /g/ preceded by /1/ than for a /g/ preceded by /r/. Perception by mature listeners shows a complementary sensitivity--when a synthetic /da/-/ga/ continuum is preceded by either /al/ or /ar/, adults hear more /g/s following /l/ rather than /r/. That is, some of the fronting information in the temporal domain of the stop is perceptually attributed to /l/ (Mann, 1980). We replicated this finding and extended it to a signal-detection test of discrimination with adults, using triads of disyllables. Three equidistant items from a /da/-/ga/ continuum were used preceded by /al/ and /ar/. In the identification test, adults had identified item ga5 as "ga,' and dal as "da,' following both /al/ and /ar/, whereas they identified the crucial item d/ga3 predominantly as "ga' after /al/ but as "da' after /ar/. In the discrimination test, they discriminated d/ga3 from da1 preceded by /al/ but not /ar/; compatibly, they discriminated d/ga3 readily from ga5 preceded by /ar/ but poorly preceded by /al/. We obtained similar results with 4-month-old infants. Following habituation to either ald/ga3 or ard/ga3, infants heard either the corresponding ga5 or da1 disyllable. As predicted, the infants discriminated d/ga3 from da1 following /al/ but not /ar/; conversely, they discriminated d/ga3 from ga5 following /ar/ but not /al/. The results suggest that prelinguistic infants disentangle consonant-consonant coarticulatory influences in speech in an adult-like fashion.     

Discovering phonetic coherence in acoustic patterns

Despite spectral and temporal discontinuities in the speech signal, listeners normally report coherent phonetic patterns corresponding to the phonemes of a language that they know. What is the basis for the internal coherence of phonetic segments? According to one account, listeners achieve coherence by extracting and integrating discrete cues; according to another, coherence arises automatically from general principles of auditory form perception; according to a third, listeners perceive speech patterns as coherent because they are the acoustic consequences of coordinated articulatory gestures in a familiar language. We tested these accounts in three experiments by training listeners to hear a continuum of three-tone, modulated sine wave patterns, modeled after a minimal pair contrast between three-formant synthetic speech syllables, either as distorted speech signals carrying a phonetic contrast (speech listeners) or as distorted musical chords carrying a nonspeech auditory contrast (music listeners). The music listeners could neither integrate the sine wave patterns nor perceive their auditory coherence to arrive at consistent, categorical percepts, whereas the speech listeners judged the patterns as speech almost as reliably as the synthetic syllables on which they were modeled. The outcome is consistent with the hypothesis that listeners perceive the phonetic coherence of a speech signal by recognizing acoustic patterns that reflect the coordinated articulatory gestures from which they arose.