Julie Gros-Louis - Academia.edu (original) (raw)

Papers by Julie Gros-Louis

Prior to first words, infants go through a period of prelinguistic vocal production, including th... more Prior to first words, infants go through a period of prelinguistic vocal production, including the well-known 'babbling' phase during which infants shift between producing only vowel-like sounds to producing more speech-like, consonant-vowel clusters. Research suggests that this transition is not simply endogenously controlled, but rather, may be facilitated by maternal responsiveness. Reference [1] showed that maternal responsiveness varies to 'distress' and 'non-distress' sounds, with mothers imitating 'non-distress' vocalizations more. Reference [2] found that mothers produce differentiated responses to 'non-distress' sounds. A recent experimental study demonstrated that positive maternal feedback to prelinguistic vocalizations influenced the production of more developmentally advanced vocalizations [3]. These studies suggest that effects of maternal responsiveness on vocal development may start during the prelinguistic phase. A second find...

2010 IEEE 9th International Conference on Development and Learning, 2010

The goal of the current research was to investigate the potential relationship between joint atte... more The goal of the current research was to investigate the potential relationship between joint attention and cooperation. Sixty-six children at 14-30 months engaged in a cooperative activity with an adult partner, who stopped participating at a specific point during the tasks. We explored whether children would continue the cooperative action when the cooperative activity was interrupted, and how they would initiate it. In addition, their joint attention abilities were assessed with Early Social Communication Scales. Results showed that children's successful cooperation with adults increased with age, and was predicted by Initiative Joint Attention (IJA). In addition, gaze alternation predicted infants' reengagement behavior during the interruption. However, no significant relations were found between Responding to Joint Attention (RJA) and cooperation. The research suggests a complex relationship between joint attention and coordinated activity when considering RJA and IJA separately.

The American Naturalist, 1996

Page 1. Vol. 147, No. 6 The American Naturalist June 1996 SEXUAL DIMORPHISM, THE OPERATIONAL SEX ... more Page 1. Vol. 147, No. 6 The American Naturalist June 1996 SEXUAL DIMORPHISM, THE OPERATIONAL SEX RATIO, AND THE INTENSITY OF MALE COMPETITION IN POLYGYNOUS PRIMATES J. С Mit ani,1 J. Gros-Louis ...

International Journal of Behavioral Development, 2013

Joint attention has been suggested to contribute to children's development of cooperation; howeve... more Joint attention has been suggested to contribute to children's development of cooperation; however, few empirical studies have directly tested this hypothesis. Children aged 1 and 2 years participated in two joint action activities to assess their cooperation with an adult partner, who stopped participating at a specific moment during the tasks. Children's joint attention skills were measured by the Early Social Communication Scales (ESCS). Results showed that children's responding to joint attention ability contributed to their successful cooperation in an activity that required parallel roles, whereas initiating joint attention ability contributed to their successful cooperation in an activity that required complementary roles. These results suggest a complex relationship between joint attention and cooperative abilities when considering RJA and IJA separately.

Infant Behavior and Development, 2012

Infant Behavior and Development, 2013

For effective prelinguistic communication, infants must be able to direct their attention, vocali... more For effective prelinguistic communication, infants must be able to direct their attention, vocalizations, and nonverbal gestures in social interactions. The purpose of our study was to examine how different styles of caregiver responses influenced infant attentional and communicative behavior in social interactions, based on prior studies that have shown influences of responsiveness on attention, language and cognitive outcomes. Infants were exposed to redirective and sensitive behavior systematically using an ABA design to examine real-time changes in infants' behavior as a function of caregiver responses. During the two baseline "A" periods, caregivers were instructed to play as they would at home. During the social response "B" period, caregivers were instructed to respond sensitively to infants' behavior on one visit and redirectively on the other visit. Results demonstrated that when caregivers behaved redirectively, infants shifted their attention more frequently and decreased the duration of their visual attention. Caregiver responses also resulted in changes in vocal and gesture production. Infants decreased their production of caregiver-directed vocalizations, gestures, and gesture-vocal combinations during in the redirective condition. Results suggest that caregiver sensitive responding to infants' attentional focus may be one influence on infants' attentional and prelinguistic communicative behavior.

For effective communication, infants must develop the phonology of sounds and the ability to use ... more For effective communication, infants must develop the phonology of sounds and the ability to use vocalizations in social interactions. Few studies have examined the development of the pragmatic use of prelinguistic vocalizations, possibly because gestures are considered hallmarks of early pragmatic skill. The current study investigated infant vocal production and maternal responsiveness to examine the relationship between infant and maternal behavior in the development of infants' vocal communication. Specifically, we asked whether maternal responses to vocalizations could influence the development of prelinguistic vocal usage, as has been documented in recent experimental studies exploring the relation between maternal responses and phonological development. Twelve mother-infant dyads participated over a six-month period (between 8 and 14 months of age). Mothers completed the MacArthur Communicative Development Inventory when infants were 15 months old. Maternal sensitive responses to infant vocalizations in the previous months predicted infants' mother-directed vocalizations in the following months, rather than overall response rate. Furthermore, mothers' sensitive responding to mother-directed vocalizations was correlated with an increase in developmentally advanced, consonant-vowel vocalizations and Correspondence should be sent to some language measures. This is the first study to document a social shaping mechanism influencing developmental change in pragmatic usage of vocalizations in addition to identifying the specific behaviors underlying development.

Many studies have documented influences of maternal responsiveness on cognitive and language deve... more Many studies have documented influences of maternal responsiveness on cognitive and language development. Given the bidirectionality of interactions in caregiver-infant dyads, it is important to understand how infant behavior elicits variable responses. Prior studies have shown that mothers respond differentially to features of prelinguistic vocalizations that reflect phonological complexity; however, studies have also found that maternal responses vary as a function of interactive contexts. Thus, it is important to examine how infant phonological features and social context interact to influence maternal responsiveness because language development occurs in social interactions and moment-to-moment behaviors influence development. In the current study, we examined how maternal responses vary relative to infant vocal production and interactional context: puppet play, toy play, and book reading. Infants produced more syllable-like, consonantvowels (CV) than vowel-like sounds (V) during book reading. Mothers responded to proportionally more CV vocalizations during book reading and puppet play than during toy play; however, it was only during book reading that mothers responded to CV sounds more than V sounds. Overall, mothers responded to CV sounds with imitations/expansions significantly more than other response types. Examining responses within contexts, however, acknowledgments were the most frequent response type, with naming responses during book reading and questions in the puppet context also occurring frequently. Therefore, maternal responses varied relative to both vocal characteristics and context, suggesting key variables in social interactions that may support language development.

Existing studies have observed a robust relationship between infants' pointing gestures and langu... more Existing studies have observed a robust relationship between infants' pointing gestures and language outcomes. By contrast, infants' overall vocal production is not related to language outcomes. One possible explanation for the association between pointing and language is that pointing gestures, as compared to vocalizations, may elicit more verbal responses from social partners that are facilitative for language learning. To test this, we observed forty-seven infants aged ; during free play with their mothers and fathers separately to compare parents' verbal responses to infants' pointing gestures and object-directed vocalizations. Results showed that, compared to object-directed vocalizations, infants' pointing elicited more verbal responses from parents, particularly object labels. Moreover, mothers were more likely than fathers to provide labels. These results may help explain why pointing is associated with indices of language acquisition, but the production of vocalizations is not.

Infant-parent interactions are bidirectional; therefore, it is important to understand how infant... more Infant-parent interactions are bidirectional; therefore, it is important to understand how infants' communicative behavior elicits variable responses from caregivers and, in turn, how infants' behavior varies with caregivers' responses; furthermore, how these moment-to-moment interactive behaviors relate to later language development. The current study addressed these concerns by observing 10-to 13-month-old infants' interactions with their mothers and measuring their language outcomes when they were 15 months old. The main results were: (1) infants were more likely to combine vocalizations with pointing when mothers were not looking at the target of the point, and when mothers did not respond about the target of the point; (2) infants' combination of vocalization and pointing behavior, especially those produced when mothers were not attending to the target object of the point, related to infants' comprehension skills at 15 months as measured by the MacArthur Communicative Development Inventory (MCDI); (3) maternal follow-in responses were related to infants' improvement in their comprehension and production scores on the MCDI. These results suggest that infants' own prelinguistic communicative acts that are produced differentially as a function of maternal attention and responses, and the maternal responses that they elicit, contribute to infants' subsequent language development.

Food-associated calls are widespread in mammalian and avian species. Researchers have based hypot... more Food-associated calls are widespread in mammalian and avian species. Researchers have based hypotheses about the function of these calls on the responses of call recipients. It is assumed that these calls have evolved to attract others to a food source because call recipients ...

Behavioral Ecology, Jan 1, 2010

We examined the relationship between singing and reproductive success in cowbirds. We amassed dat... more We examined the relationship between singing and reproductive success in cowbirds. We amassed data from 17 captive flocks (164 males, 167 females) that we have studied over 4 years. For each flock, we conducted extensive observations on social interactions as the birds competed, courted, and reproduced. We collected and incubated all eggs laid during the breeding season and performed parentage analyses on the 7 flocks with the highest levels of egg production. Finally, we measured males' song quality in playback tests. Here, we assessed what aspects of singing were associated with 1) copulation success and 2) offspring production. Results differed for these 2 measures of reproductive success because of high variance in egg production within and across groups. The overall amount of songs males directed to females, a measure of courtship persistence, was the one variable strongly associated with males' copulation success. For offspring production, there was significant between-flock variability that was more pronounced than the within-group variability. The one variable that was found to be strongly associated with eggs laid within and across groups was the amount of countersinging males produced; a measure of male-male singing competition. Song attractiveness did not predict any unique variance in either measure of reproductive success. The relationship between female egg production and male competition suggests that females may be trading off current versus future reproduction based on the opportunities available in groups to evaluate males' competitive abilities. by guest on December 16, 2016 http://beheco.oxfordjournals.org/ Downloaded from by guest on December 16, 2016 http://beheco.oxfordjournals.org/ Downloaded from White et al. • Singing and reproductive success 217 by guest on December 16, 2016 http://beheco.oxfordjournals.org/ Downloaded from 218 Behavioral Ecology by guest on December 16, 2016 http://beheco.oxfordjournals.org/ Downloaded from

Behaviour, Jan 1, 2006

The present study was motivated by a recent anomalous finding between individual competitive perf... more The present study was motivated by a recent anomalous finding between individual competitive performance and reproductive output in brown-headed cowbirds (Molothrus ater). found that adult males who were housed with juveniles outcompeted adults who were housed with other adults when they were brought together to compete for mating opportunities. Although the males in groups that contained both juveniles and adults appeared to be better in securing reproductive opportunities, these groups were found to produce fewer eggs than groups with all adult males . Because adult males were housed with juveniles, it was unclear whether the lower egg production was simply due to juveniles not reproducing or whether the adult males suffered decreased reproductive output. Is the presence of juvenile males advantageous to adult males or do they suffer reproductive consequences? In the current study, we studied four groups of captive cowbirds that differed only in the presence of juvenile males to determine what influence juvenile males have on adult male reproduction. At the end of the breeding season, we performed microsatellite parentage analysis on these four groups. Females in the two groups that contained juvenile and adult males produced fewer fertile eggs compared to females in the all-adult male aviaries. Furthermore, parentage analysis revealed that female reproductive patterns were similar in the two conditions, but females in the juvenile-adult aviaries produced fewer fertile eggs. Similarly, the males in the juvenile-adult aviaries showed a similar pattern of reproductive success as the males in the all-adult male aviaries, but had consistently lower reproductive output.

Animal behaviour, Jan 1, 2006

Male song development has been studied in detail across a range of different songbird species. Ve... more Male song development has been studied in detail across a range of different songbird species. Very little, however, is known about the development of preferences for songs in females. Here we describe a method to study female preferences outside the breeding season by documenting female responses to playbacks of songs of different developmental stages and of varying quality. We compared 'wingstroke' responses of juvenile and adult females in four groups across autumn, winter and spring. We found that adult, but not juvenile, females showed preferences for variable song that was developmentally advanced. We assessed female preferences for the songs in the breeding season by playing back songs in sound-attenuation chambers and recording the number of copulation solicitation displays females gave to each song. We detected a strong relationship between wingstroke patterns in spring and song preferences, but we did not detect this relationship in the autumn or winter. Female preferences, like male songs, appear to show seasonal and developmental plasticity.

Journal of Comparative Psychology, Jan 1, 2004

Abstract 1. In the context of foraging, many animal species produce specific calls that attract o... more Abstract 1. In the context of foraging, many animal species produce specific calls that attract others. Researchers hypothesize that these vocalizations function to inform others about food; however, few studies have investigated whether food-associated calls alone are ...

International journal of primatology, Jan 1, 2006

Since early studies of primates that identified vocalizations that attracted others to a food sou... more Since early studies of primates that identified vocalizations that attracted others to a food source, the assumed function of food-associated calls has been to inform others of the presence of food. The label food-associated calls and its implied function has led to a focus in research on many species of the costs/benefits for the signaler and recipient of informing others about the presence of food; however, without clearly identifying the calls contextually or acoustically, it is unclear if calls are specific to a feeding context and thus whether calls provide specific information about the presence of food. If calls occur exclusively in the context of feeding, information about individual identity would allow listeners to decide whether or not to approach a calling individual. I conducted acoustic and contextual analyses on food-associated calls in white-faced capuchins. I identified the calls as distinct vocalizations that occur almost exclusively in a feeding context. Discriminant function analyses demonstrate that information about caller sex and identity are encoded in the calls. Therefore, there is the potential for individuals to use acoustic information when responding to food-associated calls; however, playback experiments are necessary to test more explicitly the hypothesis that recipients are able to recognize the calls of specific individuals.

American Journal of …, Jan 1, 2010

Theory and a growing body of empirical evidence suggest that higher ranking males experience repr... more Theory and a growing body of empirical evidence suggest that higher ranking males experience reproductive advantages in group-living mammals. White-faced capuchins (Cebus capucinus) exhibit an interesting social system for investigating the relationship between dominance and reproductive success (RS) because they live in multimale multifemale social groups, in which the alpha males can have extraordinarily long tenures (i.e. they coreside with daughters of reproductive age). Genetic paternity was determined from fecal samples for 120 infants born into three social groups of wild C. capucinus at Lomas Barbudal Biological Reserve, Costa Rica. Alpha males produced far more offspring than expected by chance, and significantly high Nonac's B indices (a measure of deviation from a random distribution of RS among potentially breeding individuals) were a feature of six out of eight male tenures. The likelihood of the alpha male siring a particular offspring was predicted by the kin relationship between the mother and the alpha male, as well as the total number of males and females in the group. The almost complete lack of father-daughter inbreeding constitutes an impediment to alpha male reproductive monopolization in this population, particularly toward the end of long alpha male tenures. Am.