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Early development of gestures, object-relatedactions, word comprehension and word production, and their relationships in Italian infants A longitudinal study Alessandra Sansavinia, Arianna Bellob, Annalisa Guarinia, Silvia Savinia, Silvia Stefaninib, and Maria Cristina Casellic a
Department of Psychology, University of Bologna, Italy / b Department of Neurosciences, University of Parma, Italy / c Institute of Cognitive Sciences and Technologies, National Research Council, Italy
Our study aimed to examine longitudinally early development of gestures, object-actions (short for object-related-actions), word comprehension, and word production and their reciprocal relationships in typically developing infants. Twenty-two monolingual Italian infants were followed monthly from 0;10 up to 1;5 with the Italian short form of MacArthur-Bates CDI — Gestures and Words. Results showed that gestures, object-actions, and word comprehension increased significantly from 0;10 to 1;5, with an earlier development of gestures with respect to object-actions, while production started to increase significantly from 1;0. A developmental advantage of girls with respect to boys was found in gestures, object-actions and word comprehension. Relationships were evident between object-actions and word comprehension at all ages, between gestures and both word comprehension and word production in their phase of emergence, and between word comprehension and word production at the emergence of word production. Our findings suggest that gestures support the emergence of verbal abilities, while object-actions contribute to the construction of the representation of meanings. Keywords: gestures, object-actions, early lexicon, MacArthur-Bates CDI, gender differences
Gesture 10:1 (2010), 52–85. doi 10.1075/gest.10.1.04san issn 1568–1475 / e-issn 1569–9773 © John Benjamins Publishing Company
Early development of gestures, object-actions, word comprehension and word production
Introduction During the first phases of development, infants engage in a number of different kinds of expression. Besides vocalizations, babbling and speech, infants use gestures but they also may enact patterns of action in relation to toys and other objects which show their understanding of the nature of these objects and how they are used. According to a current theoretical approach, these patterns of action, or object-actions (short for object-related-actions), as we shall call them, develop in tandem with gestures and vocal expression, and are built on some general abilities shared with other cognitive domains and are mediated by common domain-general neural systems (Bates & Dick, 2002; Capirci & Volterra, 2008; Iverson, 2010). The period between the end of the first year and the second year is critical for the emergence of these communicative competences and for the transition from a contextualized to a symbolic and de-contextualised use of them. This has been shown in some longitudinal studies using both direct observation and parental reports (Bates, Benigni, Bretherton, Camaioni, & Volterra, 1979; Capirci, Contaldo, Caselli, & Volterra, 2005; Dale & Goodman, 2005; Harris & Chasin, 1999). In this paper we examine how the development of word production and word comprehension are related to the emergence of gestures and object-actions. By ‘gesture’ we refer to deictic gestures (request, show, point) and to various kinds of conventional expressions. These include routine gestures, such as clap hands or blow a kiss, and so-called conventional gestures, such as touching the cheek with the index finger (index to cheek) to say something tastes good, or blow to indicate something is hot. Object-actions, which, as just mentioned, are brief actions associated with specific objects or practical routines, are divided into three kinds. These are Familiar Functional Actions, such as stir with a spoon in a cup, wipe face or hands with a towel, put a phone to the ear, or lift a comb to comb the hair; Pretending to be a Parent, or Pretending Actions, as put a puppet to bed or kiss and hug a puppet; and Imitating Adult Actions, or Imitating Actions, such as sweep with a broom or put a key in the lock. Although several studies have been carried out on the transition from gestures to words and on the development of word comprehension and word production, these have not looked at how these abilities develop longitudinally, considering all of them in the same observational period. In this paper we present a systematic longitudinal analysis of the relationships among communicative gestures, objectactions, word comprehension and word production during the transition from the first to second year of life. Using a standard parental report questionnaire, as will be described in detail below, we assess the developmental trajectories of these forms of expressive behaviour at monthly intervals in a cohort of infants from 0;10 to 1;5. We look at the development of these forms of expression longitudinally. In
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addition, and also in contrast to previous work, we have analyzed the development of gestures and object-actions separately. As we shall see, the way these develop is somewhat differentiated and this allows us to postulate somewhat different functional roles for each of them.
Continuity among gestures, object-actions, and words from the first to the second year Toward the end of the first year infants begin to communicate intentionally mainly through gestures, often accompanied by vocalizations. Several studies have pointed out that between 0;8 and 0;10, typically developing infants start to perform deictic gestures (e.g., request, show, give, or point), whose referents can only be identified in the physical and social context in which communication takes place, and culturally derived gestural routines (e.g., clapping hands or waving goodbye). Some of these gestural routines (such as waving “bye-bye” or blowing on something to indicate that it is hot) will become conventional gestures during the second year of life. In addition around 1;0, slightly before the onset of word production, infants start to reproduce brief actions associated with specific objects (e.g., stir with a spoon in a cup, put a phone to the ear, a cup to the lip, a brush to the hair), here referred to as object-actions. Infants often perform these object-actions in social interactional contexts. Initially these actions have a manipulative purpose but later, through the interactional context with the caregiver, their main purpose becomes practicing meaning-making (Bates & Dick, 2002; Caselli, 1994; Caselli, Rinaldi, Stefanini, & Volterra, 2009). As Capirci and colleagues (2005) noted, the meanings shared with the caregiver through these goal directed object-actions, are later expressed in a symbolic way with representational gestures, also referred to as symbolic gestures or referential gestures, which denote a precise referent and their basic semantic content remains relatively stable across different contexts (e.g., bringing a fist to the ear means telephone). Thus, a transition from actions with objects or object-actions to representational gestures occurs. Object-actions are produced at first with a specific object, showing that the infant recognises the appropriate use of the object. The communicative and demonstrative purpose of these actions can be inferred within the interactional context when these actions are combined with communicative signals (such as alternating visual fixations between the object and the caregiver) and are responded to by the caregiver. Gradually, actions of this sort start to be produced with other objects or without objects, showing a progressive decontextualization (Iverson, 2010). Until 1;4 infants produce more gestures (deictic, routine, conventional and representational) and object-actions than words. Often they convey information by combining gestural and vocal elements, which both convey the meaning of the
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Early development of gestures, object-actions, word comprehension and word production
same referent (e.g., producing bye bye and saying “bye”) or the gesture identifies the referent and the word refers to its meaning (point to dog and saying “dog”) (Capirci, Iverson, Pizzuto, & Volterra, 1996; Pizzuto & Capobianco, 2005). Around 1;8, a shift from gestural to vocal modality occurs as revealed by a higher production of words than gestures (Iverson, Capirci, & Caselli, 1994). At this time, also, gesture-word combinations occur in which the gesture and the word are semantically related in a supplementary manner (e.g., point to a doll and saying “sleep”) and word-word combinations begin to appear (e.g., “mommy bed”) (see Volterra, Caselli, Capirci, & Pizzuto, 2005, for a review). This transition cannot be attributed to a contraction of the infants’ gestural repertoire, but is due to a parallel and comparatively greater expansion of the vocal repertoire. The transition from gesture-word combinations to word-word combinations is supported by maternal communicative strategies as when the mother replies to the infant’s gesture-word combination by translating it into a simple sentence (Goldin-Meadow, 2009).
Development of word comprehension and word production from the first to the second year In parallel to gestures and object-actions, word comprehension develops as well. As parents and psycholinguists have known for many years, infants appear to understand far more than they are able or willing to say and word comprehension precedes the development of word production (Bates, 1993; Bates, Bretherton, & Snyder, 1988). Comprehension, however, is not easy to detect. As several studies have pointed out, until 1;4–1;6 parental reports are the earliest and more reliable indicators of vocabulary development (Bates, 1993; Jahn-Samilo, Goodman, Bates, & Sweet, 2000; Ring & Fenson, 2000). For this reason, studies on early comprehension have mostly employed the MacArthur-Bates Communicative Developmental Inventory-MB-CDI, administered to parents of 8- to 17-month-old infants (Bleses, Vach, Slott, Wehberg, Thomsen, Madsen, & Basbøll, 2008; Caselli & Casadio, 1995; Fenson, Dale, Reznick, Bates, Thal, & Pethick, 1994; Fenson, Marchman, Thal, Reznick, & Bates, 2007; Hamilton, Plunkett, & Schafer, 2000; Kern, 2007). Cross-sectional (Fenson et al., 1994) and longitudinal (Harris & Chasin, 1999) studies run on word comprehension from the first to the second year of life respectively, using the MB-CDI and also direct observations, have found a spurt of this ability already between 0;11 and 1;3. By contrast, a spurt in word comprehension between 1;8 and 1;10, parallel to a spurt in word production, was found in a study employing a visual preference task (Reznick & Goldfield, 1992). The authors calculated a word comprehension score reflecting increase of attention to the referent by comparing visual fixation during a preprompt baseline with fixation following the prompt (for each word, the child observed 2 slides and was prompted to look
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at 1 named by the experimenter). Even if it is not clear whether these discordant results might depend on the instruments employed, it might be that these two different spurts represent the emergence of two different aspects of word comprehension. The former might be an increase in context-bound comprehension, while the latter an increase in linguistic, decontextualized comprehension, as the considerations by Bates & Dick (2002) about the relevance of the context in early word comprehension might suggest. Besides these quantitative changes, relevant qualitative changes have been described in the above studies. These have shown that, initially, people and object names are understood (Caselli & Casadio, 1995; Fenson et al., 2007; Kern, 2007); subsequently, when the child understands about 50 words, the proportion of object names and of predicates (verbs and adjectives) understood increases. This trend becomes more evident when about 100 words are understood, as observed also in cross-linguistic studies (Caselli, Bates, Casadio, Fenson, Fenson, Sanderl, & Weir, 1995). The above studies have also shown that word production begins around 1;0, later than word comprehension. Soon afterwards, there is usually a spurt in word production, but several longitudinal studies have shown that there is a great deal of variation in the age at which this occurs (Ganger & Brent, 2004). This variation appears related to the vocabulary size, the types of acquired lexical items and the style of acquisition (D’Odorico, Carubbi, Salerni, & Calvo, 2001). Concerning the content of words produced in the child’s early vocabulary, a trend similar to that for word comprehension has been found. Thus, at first the child uses words that refer people, onomatopoetic words (e.g., “bow-wow” for ‘dog’), and expressions such as “bye-bye”, which are part of social routines. Subsequently, names for objects become common, but when the child’s vocabulary begins to expand to beyond about 200 words, there is an increase in predicates. Word combinations appear once the child has acquired around 400–500 words, although nouns remain the most represented category (Caselli & Casadio, 1995; Caselli, Casadio, & Bates, 1999; Caselli, Pasqualetti, & Stefanini, 2007; Fenson et al., 2007; Kern, 2007; Salerni, Assanelli, D’Odorico, & Rossi, 2007). An effect of gender on the rate of early lexical acquisition has also been demonstrated in studies based on MB-CDI data and/or on tests evaluating lexical competence both in comprehension and production. Some authors have found a higher acquisition rate in girls than in boys for both word comprehension and production (e.g., Bauer, Goldfield, & Reznick, 2002; Bleses, Vach, Slott, Wehberg, Thomsen, Madsen, & Basbøll, 2008; Bornstein, Hahn, & Haynes, 2004; Fenson et al., 1994; Fenson, Pethick, Renda, Cox, Dale, & Reznick, 2000; Fenson et al., 2007), while others only in word production (Bavin, Prior, Reilly, Bretherton, Williams, Eadie, Barrett, & Ukoumunne, 2008; Bello, Caselli, Pettenati, & Stefanini, 2010; Kern, 2007 ). These different results can be explained by differences in ranges of
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Early development of gestures, object-actions, word comprehension and word production
age, sample sizes and tools (direct vs. indirect) employed. Qualitative differences in word repertoire have also been reported. Girls’ words appear more focussed on social relations and personality, and ‘objects to be cared for’, whereas boys’ words focus on naming moving objects, objects they can act on and certain food-related items (Wehberg, Vach, Bleses, Thomsen, Madsen, & Basbøll, 2008).
Relationships among gestures, object-actions, word comprehension and word production Although gestures, object-actions, word comprehension and word production are associated during the first phases of development, their relationships have been scarcely investigated and gestures and object-actions have been considered in most studies as a single ability called gestures/actions. A few cross-sectional studies have investigated the relationships between gestures/actions and either word comprehension or word production (Caselli et al., 2009; Eriksson & Berglund, 1999; Fenson et al., 1994; Fenson et al., 2007; Kern, 2007). These studies have shown that between 0;8 and 1;4 gestures/actions are highly correlated with word comprehension, measured either as phrases and/or words. In addition, a positive correlation between early emergence of pointing and early comprehension of object names has been observed in the first year of life (Harris, Barlow- Brown, & Chasin, 1995). Furthermore, Bates, Thal, Whitesell, Fenson and Oakes (1989) have found that between 1;0 and 1;4 deictic gestures as well as what they referred to as “object gestures” (same as object-actions) are more related to word comprehension than to word production. Also in the studies by Fenson and colleagues (2007), by Kern (2007) and by Caselli and colleagues (2009), the relationship between gestures/actions and word comprehension was stronger than it was with word production. Bavin and colleagues (2008) report similar findings in a longitudinal study using the MacArthur-Bates CDI which showed that the correlations between types of gestures (deictic, conventional, and routine gestures), types of actions (actions with objects, pretending to be a parent, imitating adult actions, same as Familiar Functional Actions, Pretending Actions, and Imitating Actions) and word comprehension at 1;0 were stronger than with word production. Thus, until almost 1;4 production of gestures/actions, considered all together, shows a positive and strong relationship with the understanding of contextualised phrases and lexical items, but a weak relationship with word production (e.g., the infant produces the gesture of combing and understands the word “comb” within an interactional context, but does not say “comb”). Concerning the relationship between word comprehension and word production, besides the developmental lag already discussed above (Bates et al., 1988), positive correlations have been found by some cross-sectional studies considering
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the entire period between 0;8 and 1;4 (Fenson et al., 1994; Fenson et al., 2007; Kern, 2007) and by a longitudinal study at 1;0 and at 2;0 (Bavin et al., 2008).
Aims of the present study The studies described above suggest that there is a continuity between gestures, object-actions, word comprehension, and word production. However, few longitudinal studies of the emergence and acquisition of these abilities have been carried out, and so far there has been no longitudinal study in which observations have been made at monthly intervals and in which all four of the communicative abilities here being discussed have been considered together. Given this, the first aim of the present study was to investigate longitudinally with close and repeated assessments (monthly from 0;10 to 1;5) the developmental trajectories of gestures, object-actions, word comprehension and word production in infants with typical development with a focus on the time of emergence and rate of development of these abilities. In order to investigate these developmental trajectories more deeply, a detailed description of the development of different types of gestures and object-actions and of different categories of word comprehension and of word production was carried out. In addition, the gender of the infants observed was taken into account, as has already been done in studies of word production and by some authors in studies of word comprehension. Thus we shall be able to see if there are gender differences in regard to object-actions and gestures, as well. This has not been examined before. Furthermore, most studies which have examined the relationships among gestural and lexical abilities, have considered the production of gestures and objectactions as a single competence. In those studies in which these two have been kept separate, however, all ages have been considered together (Bates et al., 1989; Caselli et al., 2009; Fenson et al., 2007) or only a few age points have been considered (0;8, 1;0, and 2;0; Bavin et al., 2008). New research is necessary, therefore, if we are to understand more deeply the complexity of the relationships between these competencies during early language development. In particular, longitudinal designs with intensive observations during the second year of life could be very useful. Accordingly, our second aim was to examine the relationships among gestures, object-actions, word comprehension and word production and how these change, monthly, from 0;10 to 1;5. These results will allow us to understand the development of communication and language taking into account at the same time all the abilities involved and how they are related. In the present study, carried out with typically developing Italian children, we have chosen to evaluate gestures, object-actions, word comprehension and word production through the MB-CDI, which, as shown by several studies, is
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Early development of gestures, object-actions, word comprehension and word production
particularly reliable in this developmental period to assess the above competences and can be used also longitudinally. In particular, data were collected through the Italian short form of the questionnaire MB-CDI Il Primo Vocabolario del Bambino – PVB – Gestures and Words (Caselli, Bello, Pasqualetti, Rinaldi, & Stefanini, in preparation). The short forms of the MB-CDI have in fact been recently developed in different languages in order to quickly and accurately assess early language development and significant correlations with the long form have been demonstrated (e.g., Caselli et al., 2007; Eriksson, Westerlund, & Berglund, 2002; Fenson et al., 2000; Recchia, Stefanini, Pasqualetti, & Caselli, 2006).
Method Participants Thirty Italian monolingual infants were recruited for this study. They were followed longitudinally from 0;10 to 1;5. All infants were at least 37 weeks’ gestation, had had uneventful births, were singletons, were apparently in good health and had no recurrent otitis during the period of observation. Since we chose to include only infants whose parents completed the questionnaires (8 questionnaires), each month on a regular basis, data on 22 participants (10 girls; 12 boys) were available after excluding 8 families who missed to fill in one or more questionnaires during the research period. Parents were requested to fill the questionnaire Il Primo Vocabolario del Bambino – PVB – Gestures and Words – short form (Caselli et al., in preparation), each month in the week corresponding to the infant’s birthday. Means of infants’ age at each administration of the questionnaire were: 0;10.2, 0;11.2, 1;0.2, 1;1.2, 1;2.2, 1;3.2, 1;4.2, 1;5.2 (years;months.days). Additional information on the family structure, education and occupation of the parents and the day-care situation of the infant was collected by a basic information form included in the questionnaire. The sample consisted of 19 first-born children (86%) and 3 infants (14%) who had one sibling. The educational level of the 44 parents was distributed as follows: five had a low educational level (basic), 10 had a medium level (high school) and 29 had a high level (University/Master’s degree or more). The educational level of parents of our sample was quite high in comparison to the general Italian population, but similar to other samples who participated in analogous international longitudinal studies (Wheberg et al., 2008; Bernhardt, Kemp, & Werker, 2007). All parents had an occupation consistent with their educational level, and none of the families were economically disadvantaged. All infants were living with both their parents: the majority of them was cared during the day
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by parents or grandparents, 4 infants (18.2%) attended the nursery school from the beginning of the study, while other 3 infants (13.6%) started to do so from 1;2–1;3.
Materials and Procedure During the first contact with the parents the purpose of the study was explained. The parental questionnaire, – PVB – Gestures and Words – short form (Caselli et al., in preparation), and a letter summarizing the research project was given to them. To help in maintaining the sample, we contacted the families by phone each month. Parents returned the completed questionnaires in person or mailed them back to the researchers. The Italian short form of the questionnaire, PVB – Gestures and Words, derives partially from the long form of PVB – Gesture and Words (Caselli & Casadio, 1995). The standardization of the short form with an Italian population of about 600 infants between 0;8 and 2;0 has been recently completed (Caselli et al., in preparation). High correlations for word comprehension (r = .87, p
