Nobuo Masataka

Vocal Learning of Japanese and Rhesus Monkeys

Foraging vocalizations given by Japanese and rhesus momkeys reared by their biological mothers differed from each other in a single parameter. Calls made by a Japanese monkey fostered by a rhesus female were dissimilar to those of conspecifics reared by their biological mothers, but similar to those of rhesus monkeys reared by their biological mothers, and the vocalizations given by rhesus monkeys fostered by Japanese monkey mothers were dissimilar to those of conspecifics reared by their biological mothers, but similar to those of Japanese monkeys reared by their biological mothers. Playback experiments revealed that both Japanese and rhesus monkeys distinguished between the calls of Japanese monkeys reared by their biological mothers and of the cross-fostered rhesus monkeys on one hand, and the vocalizations of rhesus monkeys reared by their biological mothers and of the cross-fostered Japanese monkey on the other hand. Thus, production of species-specific vocalizations was learned by each species, and it was the learned species-difference which the monkeys themselves discriminated.

Cross-Cultural Analysis of Social Competence and Behavior Problems in Preschoolers.

A multi-national study using the Social Competence and Behavior Evaluation Inventory (SCBE-30) was conducted to investigate preschool childrens social and emotional development across cultures. A total of 4,640 children from eight participating countries, including Austria, Brazil, Canada, China, Italy, Japan, Russia, and the United States were evaluated by their preschool teachers. The main objective of the study was to validate the SCBE-30 in each country and build a cross-cultural data set for the investigation of universals, as well as cultural differences, in the development of preschool childrens social competence and the frequency and type of their behavioral problems. Results provide a clear case for the structural equivalence of the SCBE-30 across all samples, for universals in the structure of early social behavior, and possibly some differences that may be attributed to culture. The pattern of gender differences found in North American samples was found to generalize across cultural contexts as preschool boys were universally reported to be significantly more aggressive and viewed as less socially competent than girls. Age differences were also found in all eight samples reflecting increasing competence in older children, however age trends in the prevalence of behavior problems were culture specific.

Why early linguistic milestones are delayed in children with Williams syndrome: late onset of hand banging as a possible rate–limiting constraint on the emergence of canonical babbling

In the present study, eight children with Williams syndrome were observed every 2 weeks between 6 months and 30 months of age when interacting with their mothers. When the collected data were transcribed in terms of both linguistic and motor activities, overall delay was found in terms of the onset of canonical babbling, first words, as well as various motor milestones in every child. The degree to which acquisition of each of the milestones was delayed was individually variable. Nevertheless, the onset of hand banging was found to be an indicator that predicted the onset of canonical babbling consistently among the children. Once canonical babbling was produced, moreover, the onset of first words was recorded during a following 2 to 3 month period. These findings appear to indicate the possibility that development of the motor ability to perform such rhythmic motor activity as hand banging acted as a control parameter for production of canonical syllables in the children.

Co‐occurences of preverbal vocal behavior and motor action in early infancy

This study reports on co-occurrence of vocal behaviors and motor actions in infants in the prelinguistic stage. Four Japanese infants were studied longitudinally from the age of 6 months to 11 months. For all the infants, a 40 min sample was coded for each monthly period. The vocalizations produced by the infants co-occurred with their rhythmic actions with high frequency, particularly in the period preceding the onset of canonical babbling. Acoustical analysis was conducted on the vocalizations recorded before and after the period when co-occurrence took place most frequently. Among the vocalizations recorded in the period when co-occurrence appeared most frequently, those that co-occurred with rhythmic action had significantly shorter syllable duration and shorter formant-frequency transition duration compared with those that did not co-occur with rhythmic action. The rapid transitions and short syllables were similar to patterns of duration found in mature speech. The acoustic features remained even after co-occurrence disappeared. These findings suggest that co-occurrence of rhythmic action and vocal behavior may contribute to the infant’s acquisition of the ability to perform the rapid glottal and articulatory movements that are indispensable for spoken language acquisition.

Preference for infant-directed singing in 2-day-old hearing infants of deaf parents.

L. J. Trainor (1996) reported preferences for infant-directed versus infant-absent singing in English in 4-7-month-old hearing infants of English-speaking hearing parents. In this experiment, the author tested preferences for infant-directed singing versus adult-directed singing in 15 two-day-old hearing infants of deaf parents for a Japanese and an English play song. Using a modified visual-fixation-based auditory-preference procedure, the author found that infants looked longer at a visual stimulus when looking produced infant-directed singing as opposed to adult-directed singing. These results suggest that infants prefer infant-directed singing over adult-directed singing and that the preference is present from birth and is not dependent on any specific prenatal or postnatal experience.

Motherese in a signed language

It is well known that when they address their infants, mothers substantially alter the acoustic characteristics of their speech. In this experiment, the possibility was explored that a similar phenomenon might occur in a signed language. Eight deaf mothers, each of whom used Japanese Sign Language as a first language, were observed when interacting with their deaf infants and when interacting with their deaf adult friends. When communicating with their infants, the mothers used signs at a significantly slower tempo than when communicating with their friends. They tended to repeat the same sign frequently, and the movements associated with each sign were somewhat exaggerated. Thus, a phenomenon quite analogous to motherese in maternal speech was identified. The possible functional significance of this phenomenon is discussed.

Categorical responses to natural and synthesized alarm calls in Goeldi's monkeys (Callimico goeldii)

The responses of Goeldis monkeys to their natural alarm calls as well as synthesized versions varying in the acoustic parameters that defined the calls were studied. The response patterns, which were subject to a distinct change only with an increase of 0.2 kHz in the frequency range of the modulating sweep, appeared to reflect strict underlying perceptual boundaries. This was analogous to the categorical perception that humans show with speech sounds. Supernormal releaser was found, and the characteristics of its acoustic structure were assessed in terms of the environmental influences of the physical situation in which alarm calls must be emitted.

Temporal rules regulating affiliative vocal exchanges of squirrel monkeys

All contact calls (chuck vocalizations) occurring in a group of ten captive squirrel monkeys were recorded over 200 minutes. The temporal distribution of inter-chuck intervals was bimodal, with one peak at short intervals (0.1-0.2 sec) and another peak at relatively longer intervals (1.4-1.5 sec). Sequalae analysis revealed that in two consecutive chucks separated by intervals longer than 0.5 sec, the following call took place independently of the preceding chuck. If two chucks occurred at intervals of 0.5 sec or less, on the other hand, the following caller vocalized in response to the preceding vocalization. The results indicate that if squirrel monkeys intend to respond to chucks given by others, they should do so within the next 0.5 sec. Otherwise, they should not vocalize during that period. This temporal rule allows the animals to determine whether a caller of the following chuck really responds to the preceding call or not, when two chucks are heard consecutively.

Effects of Contingent and Noncontingent Maternal Stimulation on the Vocal Behaviour of Three- to Four-Month-Old Japanese Infants.

A total of 48 male infants experienced either conversational turn-taking or random responsiveness of their mothers when aged 0;3 and 0;4. In both periods, the infants rate of vocalizing was not significantly influenced by the contingency of the mothers response, but contingency altered the temporal parameters of the infants vocal pattern. Infants tended to produce more bursts or packets of vocalizations when the mother talked to the infant in a random pattern. When the infants were aged 0;3 such bursts occurred most often at intervals of 0.5-1.5 sec whereas when they were aged 0;4 they took place most frequently at significantly longer intervals, of 1.0-2.0. The difference corresponded to the difference between intervals with which the mother responded contingently to vocalizations of the infant at 0;3 and at 0;4. While the intervals (between the onset of the infants vocalization and the onset of the mothers vocalization) rarely exceeded 0.5 sec when the infant was aged 0;3, they were mostly distributed between 0.5 and 1.0 sec when he was aged 0;4. After vocalizing spontaneously, the infant tended to pause as if to listen for a possible vocal response from the mother. In the absence of a response, he vocalized repeatedly. The intervals between the two consecutive vocalizations were changed flexibly by the infant according to his recent experience of turn-taking with the mother.

The efficacy of musical emotions provoked by Mozart's music for the reconciliation of cognitive dissonance

Debates on the origin and function of music have a long history. While some scientists argue that music itself plays no adaptive role in human evolution, others suggest that music clearly has an evolutionary role, and point to musics universality. A recent hypothesis suggested that a fundamental function of music has been to help mitigating cognitive dissonance, which is a discomfort caused by holding conflicting cognitions simultaneously. It usually leads to devaluation of conflicting knowledge. Here we provide experimental confirmation of this hypothesis using a classical paradigm known to create cognitive dissonance. Results of our experiment reveal that the exposure to Mozarts music exerted a strongly positive influence upon the performance of young children and served as basis by which they were enabled to reconcile the cognitive dissonance.