Infant use of relative motion as information for form: Evidence for spatiotemporal integration of complex motion displays

Previous studies of infants’ ability to integrate and to utilize relative motion as information for form in the absence of structural cues have primarily involved motions that are uniform in rate, direction, and path within the form to be constructed. In the present study, we examined infants’ ability to integrate relative motion information from motions that are nonuniform along these dimensions, and from this integrative process to construct a coherently rotating two-dimensional form. Infants’ ability to integrate nonuniform motion was measured with regard to their ability to discriminate the rotating form from a noncoherent control display containing the same absolute motions. The results showed that discrimination of the coherent and incoherent displays was not demonstrated until 7 months of age. Two additional experiments were conducted to rule out the possibility that this discrimination was based on the detection of local regions of coherence, rather than the perception of the global rotating form. In both experiments, the results did not support discrimination based exclusively on local cues alone. From the combined results of all three experiments, we conclude that infants demonstrate the capacity to integrate the information contained within nonuniform trajectories into a coherent structure by 7 months of age.     

Asymmetries in the regulation of visually guided aiming

An experiment was conducted to examine the contribution of sensory information to asymmetries in manual aiming. Movements were performed in four vision conditions. In the full-vision condition (FV), subjects were afforded vision of both the hand and the target throughout the course of the movement. In the ambient-illumination-off condition (AO), the room lights were extinguished at movement initiation, preventing vision of the moving limb. In the target-off (TO) condition, the target was extinguished upon initiation of the movement. In a no-vision (NV) condition, ambient illumination was removed and the target was extinguished upon initiation of the response movement. Results indicated that accuracy was superior in the full-vision and target-off conditions and when movements were made by the right hand. Movements made by the right hand were also of shorter mean duration. The magnitudes of performance asymmetries were uninfluenced by vision condition. Analyses of movement kinematics revealed that movements made in conditions in which there was vision of the limb exhibited a greater number of discrete modifications of the movement trajectory. On an individual-trial basis, no relationship existed between accuracy and the occurrence of discrete modifications. These data suggest that although vision greatly enhances accuracy, discrete modifications subserved by vision reflect the imposition of nonfunctional zero-order control processes upon continuous higher-order control regimes.     

Assessment: what role the assessor?

The advent of automated assessment contains the seeds of both threat and promise for professional assessors. Placing the problem in the historical and sociological contexts, this article examines computer-based test interpretation (CBTI) and the frequently misunderstood role of actuarial data in relation to it. I argue that sound clinicianship is central not only to the development of adequate CBTI systems, but also to the systems' appropriate and skillful use in practice. When properly utilized by otherwise well-qualified clinicians, CBTI can substantially enhance practice.     

Phonological and form class relations in the lexicon

Two experiments were conducted to examine the structure of the mental lexicon. A lexical search of American English, using the Brown corpus (Francis and Kucera, 1982), revealed a skewed, frequency-dependent distribution in which the syntactic classes of noun and verb are distinguished in terms of the phonological classification of their vowels. Among high-frequency words, nouns are more likely to have back vowels (57%) rather than front vowels (43%) and verbs more likely to have front vowels (62%) than back vowels (38%). This distribution, however, does not hold for low-frequency nouns and verbs in the language. Noun and verb stimuli containing front and back vowels were examined in both an auditory noun/verb categorization task and an auditory lexical decision task. In general, the phonotactic composition of nouns and verbs in the lexicon was shown to have perceptual consequences. Listeners seem to be differentially sensitive to incoming sound patterns on the basis of distributional properties of the lexicon.These experiments were conducted at the Brown University Phonetics Laboratory. The technical expertise of John Mertus and Andrew Mackie as well as the help of Martha Burton and Annemie Witjes are gratefully acknowledged.     

Conversational time patterns and mutual influence in parent-child interactions: A time series approach

Mutual influencing processes are assumed to be the basic building blocks in establishing parentchild bonding and in influencing cognitive and language behavior. A study by Jasnow and Feldstein (1986) revealed that, within the temporal domain of speech, preverbal (9-month-old) infants and their mothers exhibit a pattern of mutual influence (attunement) in their average durations of switching pauses. The general purpose of this research was to extend those findings to children with higher verbal functioning. In addition, parent and child genders, nature of the interaction, and specific aspects of parents' personalities, expressiveness, and instrumentality were considered. Each parent interacted with their 4-or 5-year-old son or daughter in each of two conversations—unstructured (social conversation) and structured (task activity). Conversations were processed by an automated computer system yielding objective measure of turns, vocalizations, pauses, and switching-pause durations. To examine interspeaker influence or attunement of temporal speech patterns, influence coefficients were computer for each speaker on a turn-by-turn basis using time series regression. Analysis of these coefficients revealed that: (1) Mutual influence is most evident with switching-pause duration. (2) Structure in the conversation (as defined by the task or parental instrumentality) seems to facilitate attunement for vocalization and switching pause duration. (3) Attunement with girls seems to occur equally well with both parents, while boys exhibit a style of temporal patterning influence which suggests greater identification with the father. (4) Expressiveness seems to facilitate attunement to the child's switching-pause duration.     

A multidimensional scaling analysis of vowel discrimination in humans and monkeys

Multidimensional scaling (MDS) was used to compare perceptual maps for 10 synthetic English vowels in humans and Old World monkeys (Macaca fuscata andCercopithecus albogularis). Subjects discriminated among the vowels using a repeating background procedure, and reaction times were submitted to an MDS analysis to derive measures of perceived similarity. The dimensions that emerged related to the frequencies of the first(F1), second(F2), and third(F3) formants. Human data indicated a good match to previous MDS studies using rating procedures or confusion matrices: The dominant dimension mapped onto vowelF2, the phonetically most important formant, and the second and third dimensions mapped ontoF1 andF3, respectively.For monkeys, equal weightings occurred forF1 andF2, andF3 was not clearly represented. Monkey sensitivity to the formants appeared to relate to formant amplitudes. If monkeys are giving an accurate representation of the psychoacoustic relations among the formants, then our human results suggest that species-specific mechanisms, reflecting the salience of the phonetic feature of advancement, may contribute to vowel coding in humans.     

“My big sister the town supervisor”: Family leadership training is not just for boys

This study investigates gender similarity in the effects of birth order upon political leadership. Town supervisors were the leaders studied as there are a considerable number of women who attain this level of leadership. Questionnaires about birth order and family size were gained from 66 women who were town supervisors in New York State in 1992, and compared to a randomly selected sample of 57 male town supervisors. It was found that women as well as men town supervisors were more likely to have been first born in their families. However, whereas gender does not apparently influence the relevance of birth order for leadership, it clearly does exert an influence on the level of political leadership attained. Women town supervisors gained their positions in towns that were considerably smaller than the towns led by the male supervisors. Discussion concerned the nature of family experiences that contribute to leadership training, including those that may be different for girls and boys. Further research is needed to clarify barriers to female assertion of political leadership at more senior levels, because as this study shows, female leadership is being trained in families.     

MENSTRUAL JOY The Construct and Its Consequences

Fifty female college students participated in a study of women's health. In a counterbalanced design, half of the participants completed the Menstrual Joy Questionnaire (MJQ) and the Menstrual Attitude Questionnaire (MAQ) in the first testing session. A week later they completed the Menstrual Distress Questionnaire (MDQ) and the Menstrual Attitude Questionnaire. The other participants completed the MDQ and MAQ in the first session and the MJQ and MAQ in the second. A multivariate analysis of variance revealed that those who received the MJQ first reported more positive cyclic changes on the MDQ and more positive attitudes on the MAQ. A follow-up study of 40 college students examined their responses to the MJQ. Participants reported that they were surprised or incredulous; most had not previously considered positive aspects of the menstrual cycle. Thirty percent reported that the MJQ had caused them to look at menstruation in a different way.     

Memory trace development along a coarse-to-fine dimension; a study supporting a progressively finer attributes theory

This study presents two experiments that demonstrate that the memory trace of a tobe-remembered item develops along a dimension (continuum) from coarse/general to fine/specific. Similarly, forgetting is shown to be a reverse movement along this dimension from fine to coarse, as increasingly less fine attributes are lost. The attribute acquisition pattern of this Progressively Finer Attributes Theory is robust and predictable, valid for experimentally unstructured (Experiment 2) as well as experimentally structured (Experiment 1) material.