Joanna Blake

Form and function in the development of pointing and reaching gestures

Abstract Twelve 4-month-olds, twelve 8-month-olds, and twelve 12-month-olds were videorecorded at home in face-to-face interactions with their mothers and in structured situations designed to elicit pointing and reaching gestures. Pre-pointing (index finger extension) occurred in all age groups but was not mapped onto indicative situations; it was elicited most by arousing situations in 4-month-olds. Its form showed continuity across age groups in that pre-points were not bimanual at any age, but there was also discontinuity in form in that pre-points by 12 months were prolonged rather than brief and were predominantly right-handed. Undirected pre-reaching was also more frequent in arousing situations and dropped out after 4 months. Poking, pointing in a book, and pointing to an object did not occur in the majority of infants until 12 months. Despite shared components between early movements and mature pointing, changes in both form and function cast doubt on interpretations of early finger extension as “pointing”.

Evaluating Quantitative Measures of Grammatical Complexity in Spontaneous Speech Samples.

The validity of MLU and a measure of syntactic complexity were tested against LARSP on spontaneous speech samples from 87 children, ranging in age from 1;6 to 4;9. Change in some LARSP clausal measures was found across MLU stages up to MLU 4.5. For the measure of syntactic complexity, no such ceiling was found for the clausal connectivity score in LARSP or for average clausal complexity in LARSP. Neither MLU nor the measure of syntactic complexity indexed LARSP phrasal complexity. It is concluded that MLU is a valid measure of clausal complexity up to 4.5 and that our measure of syntactic complexity is more valid at more advanced stages.

The Relationship between Memory Span and Measures of Imitative and Spontaneous Language Complexity in Preschool Children

Preschool children, aged 2 to 5 years, were given a memory task that required them to repeat a list of animal names and a sentence imitation task. A sample of their spontaneous speech was also recorded. Word span was found to predict sentence imitation scores across the whole preschool age range. Word span and chronological age (CA), together, also predicted the mean length of utterance in spontaneous speech in younger preschool children. In a replication with children aged 2 to 3 years, word span predicted mean length or utterance (MLU) better than both CA and mental age (MA). These results extend previous findings regarding the relationship between word span and language imitation to younger preschool children. They also support the notion of a memory constraint on early spontaneous language. Increasing mastery of linguistic rules appears to obviate a memory constraint on spontaneous language, at least with these measures.

Developmental change in visual information processing under backward masking

Abstract Four-year-olds, eight-year-olds, and college students were compared with respect to their speed and strategy for processing form information in a pointing-recognition task. The target form arrays, varying in size from one to four forms, were presented tachistoscopically, followed by a masking array at varying intervals. No age differences in processing speed were found on single-item arrays, but four-year-olds were progressively slower as array size increased. A selective processing condition resulted in longer processing times for all S s but was differentially more difficult for four-year-olds. Under the full report conditions, all S s showed a parallel independent processing strategy as array size increased from one to two items, but four-year-olds did not apply this strategy as efficiently as older S s. As array size increased from two to four items, only adults and eight-year-olds continued to show parallel independent processing, up to a limit. This age difference in processing strategv for the largest arrays may underlie age differences that have been found in short-term memory capacity.

Mother-infant object involvement at 9 and 15 months: relation to infant cognition and early vocabulary

This study investigated maternal verbal and nonverbal behaviours during mother-infant object involvement episodes and their relation to infant cognitive level and productive vocabulary. Thirty mother-infant dyads were observed at home during 20 minutes of play at 9 months and 10 minutes of play at 15 months with two different toys. Developmental change in maternal scaffolding behaviours was sensitive to toy difficulty. Scaffolding at both ages was related to the Bayley Mental Development Index (MDI), and scaffolding at 15 months was related concurrently to infant vocabulary. Labelling at 15 months, under both joint and non- joint attentional conditions, was related both to Bayley MDI and to concurrent infant vocabulary. Verbal behavioural directives at both ages were related to Bayley MDI and at 15 months were related concurrently to infant vocabulary. Attention-getting directives decreased with age and were unrelated to either MDI or vocabulary. Somewhat different results were obtained with frequencies vs. proportional frequencies of types of maternal verbalizations,

Gestures accompanying speech in specifically language-impaired children and their timing with speech

The repertoire and timing of gestures accompanying speech were compared in children with specific language impairment (SLI), aged 5—10 years, in typically developing peers (CA), individually matched on age and nonverbal IQ, and in younger language-matched (LM) children. They were videotaped in two tasks, recounting a cartoon and describing their classroom. Three types of gestures were coded — iconics, deictics and beats — and the synchrony of these gestures with speech was examined in terms of number of words encompassed, grammatical speech category at gesture onset, and relationship of iconic gestures to the concept expressed in speech. All groups used more deictic gestures in the classroom description task. SLI children differed from the comparison children only in their use of iconic gestures. They produced somewhat more of these, used them more often to replace words, and began them more often on a noun phrase object. Otherwise, language proficiency, at least as measured by standardized tests, did not appear to impact the gestural system. The fact that, for all groups, most iconic and deictic gestures began on the noun phrase subject indicates a close synchrony between gesture and speech onset.

Patterns in babbling: a cross-linguistic study

Three Canadian-English infants and three Parisian-French infants were filmed bi-weekly for three to five months, from the age of 0;9 or 0;11 until 1;2, at home in naturalistic interaction with a parent. Their babbled utterances were transcribed phonetically and categorized according to consonant-type and vowel-type. The contexts for each utterance were described in terms of both specific and more general contextual categories. Observed frequencies of co-occurrences between phonetic and contextual categories were compared to expected frequencies, and deviations were considered to be patterns in babbling. Patterning increased after age 1;0 for most infants, and from 1% to 30% of each infants babbled utterances recurred in particular contexts with a greater-than-expected frequency. Similarities in patterns were found both within and across language groups. These sound-meaning correspondences in babbling are viewed as continuous with early situation-bound meaning in words.

Sound-meaning Correspondences in Babbling.

The hypothesis that prelinguistic vocalizations contain extensive and systematic sound-meaning correspondences was examined through an exhaustive analysis of the babbling of five infants in their second year. These infants were videotaped over a period of three to six months at home and at a day-care centre. Their babbled utterances were transcribed phonetically and categorized according to consonant-type and vowel-type. Contexts for each utterance were also categorized, primarily according to the infants simultaneous action. A quantitative analysis of co-occurrences between phonetic and contextual categories determined that across infants between 14 and 40% of utterances recurred in particular contexts with a greater than expected frequency. These findings support Hallidays (1975 a ) notion that babbling is not entirely random but contains consistent sound-meaning relations that are not adult-modelled. They also extend the notions of continuity between prelinguistic and linguistic stages of development to the semantic domain.

The Development of Communicative Gestures in Japanese Infants

Twelve Japanese infant-mother dyads were video-recorded at home in naturalistic interaction approximately every two weeks at varying ages between 9 and 14 months. Changes in their gestural repertoire that were similar to other groups studied previously were: an increase over sessions in Comment gestures, namely pointing but not showing, and a decrease in overall Request gestures, particularly reaching. Request gestures involving cognizance of agency increased, however. Increases in Object exchange gestures and decreases in Protest/Rejection and Emotive gestures found in previous studies were not replicated in this group. Agency gestures after 12 months were related to number of words understood, as reported on the JCDI. There was good agreement on the whole between gestures reported by mothers on the JCDI and the same gestures observed directly. These results provide some support for the universality of key gestural changes considered important for language acquisition.

The nature of the cognitive deficit in specific language impairment

Fifteen language-impaired children between 3 and 5 years and 15 non-impaired children matched on sex, age, and non-verbal IQ were compared on classification, symbolic play, spatial memory and verbal memory tasks. The two groups differed only on the verbal memory tasks, and it was particularly the verbal sequential memory task that predicted language production, both Reynell expressive scores and MLU from spontaneous speech samples. These findings suggest that sequential processing/memory of verbal items is a critical factor in language impairment, while classi fication, symbolic play and spatial memory are not problematic.