Research in Developmental Disabilities 35 (2014) 3379–3385
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Research in Developmental Disabilities
Object-related generativity in children with Down syndrome§ Deborah J. Fidler a,*, Elizabeth Will a, Lisa A. Daunhauer a, Brianne Gerlach-McDonald a, Jeannie Visootsak b a b
Human Development and Family Studies, Colorado State University, 1570 Campus Delivery, Fort Collins, CO 80523, USA Departments of Human Genetics and Pediatrics, Emory University, 2165 N. Decatur Rd., Decatur, GA 30033, USA
A R T I C L E I N F O
A B S T R A C T
Article history: Received 3 June 2014 Accepted 7 July 2014 Available online 6 September 2014
Children with Down syndrome (DS) show challenges in some aspects of goal-directed behavior when compared to developmentally matched children (Daunhauer et al., 2014; Lee et al., 2011), particularly in the area of goal-directed action on objects (Fidler et al., 2005a,b). In this study, we examined one aspect of goal-directed action on objects, objectrelated generativity, in school-aged children with DS (n = 52), a developmentally matched group of children with intellectual disability, but not Down syndrome (DD; n = 21), and a group of chronologically younger, but developmentally matched typically developing children (TD; n = 34). We administered the Leiter-R, the Oral and Written Language Scales (OWLS), and an Object-Related Generativity Task, which involved 2 min of unstructured play with a variety of objects that have divergent usages. Children with DS generated significantly fewer instances of initiating actions on new objects than children in both comparison groups, were less likely to produce novel functional action on any object (new or familiar) than TD children, and they showed fewer instances of novel functional object engagement with new objects overall than TD children. Frequency of acts on new objects in DS was associated with Leiter-R Form Completion and Repeated Patterns Raw Scores and OWLS Listening Comprehension Raw Scores. These findings contribute to the growing knowledge base regarding goal-directed behavior and self-regulation in individuals with Down syndrome. Implications for education and intervention are discussed. ß 2014 Elsevier Ltd. All rights reserved.
Keywords: Down syndrome Generativity Goal-directed behavior
1. Introduction Children with Down syndrome (DS) show relative challenges in aspects of goal-directed behavior when compared to developmentally-matched children (Daunhauer, Fidler, Lee, Will, & Hepburn, 2014; Fidler, Hepburn, Mankin, & Rogers, 2005; Fidler, Philofsky, Hepburn, & Rogers, 2005; Lee et al., 2011). In particular, the early development of goal-directed action on objects appears to be an area of impairment in infants with DS (de Campos, da Costa, Savelsbergh, & Rocha, 2013; MacTurk, Vietze, McCarthy, McQuiston, & Yarrow, 1985) and toddlers with DS (Fidler, Philofsky, et al., 2005) relative to overall developmental status. Two-year-old children with DS plan notably less optimal strategies than MA-matched children
§ The authors are grateful to the children and families who graciously contributed their time to this project. This study was funded by the U.S. Department of Education, National Institute of Disability and Rehabilitation Research (H133G100197) and the U.S. Department of Education, Institute of Educational Science, Special Education Research Grants (R324A110136). * Corresponding author. Tel.: +1 970491 7870. E-mail addresses: Deborah.fi[email protected] (D.J. Fidler), [email protected] (E. Will), [email protected] (L.A. Daunhauer), [email protected] (B. Gerlach-McDonald), [email protected] (J. Visootsak).
http://dx.doi.org/10.1016/j.ridd.2014.07.024 0891-4222/ß 2014 Elsevier Ltd. All rights reserved.
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on an object retrieval task that involves minimal motor demands (obtaining a desired object through the opening of a clear box; Fidler, Hepburn, et al., 2005). Similar findings have been observed when children with DS complete a comprehensive battery of object-related planning tasks (e.g. putting a necklace in a cup, putting coins in a coin bank; Fidler, Philofsky, et al., 2005). Understanding the complex pattern of challenge and competence in this area in DS may be of particular importance in that the ability to formulate actions on objects during early development has been found to predict later academic outcomes in typically developing children (Bornstein, Hahn, & Suwalsky, 2013). Effective planning with objects has also been concurrently linked to adaptive behavior outcomes and early instrumental communication in young children with DS (Fidler, Hepburn, et al., 2005). Recent evidence also suggests that object-related behavior may affect the ways that children with DS respond to early intervention. Fey, Yoder, Warren, and Bredin-Oja (2013) recently reported that the dimension of ‘object interest’ moderated intervention effects for preschoolers with DS in a rigorous communication/language focused early intervention program. Object interest was coded in the context of a Developmental Play Assessment where children were presented with sets of toys for 5 min segments, with minimal experimenter scaffolding offered. The specific dimension of object interest was operationalized as the number of different toys with which a child engaged in functional or symbolic play. A second dimension of ‘object knowledge’ was operationalized as the number of different play acts (functional or symbolic) that the child engaged in. Fey et al. (2013) reported that the object interest variable moderated treatment response in the areas of receptive and expressive vocabulary both at the end of the intervention, and after a 6 month post-intervention follow-up assessment. Despite the fact that children with DS have been shown to demonstrate challenges in goal-directed action on objects relative to developmentally matched peers, the dimension of object-related behavior in DS remains poorly characterized. There is some suggestion that during the first year of life, infants with DS specifically show impoverished reaching for and manual exploration of objects in comparison to TD infants (de Campos et al., 2013; MacTurk et al., 1985d). Toddlers with DS have also been shown to produce less optimal reaching strategies for goal-directed planning with objects (Fidler, Hepburn, et al., 2005; Fidler, Philofsky, et al., 2005). A more comprehensive account of the specific nature of object-related behavior in childhood in DS will shed light on this potentially important dimension, and will enable researchers to address this profile to enhance intervention and educational outcomes. To understand the specific presentation of object-related behavior outcomes in DS during childhood, it may be important to examine and describe performance on the dimension of object-related generativity. Object-related generativity is defined here as the ability to flexibly produce a variety of behaviors and strategies on a variety of novel objects. In particular, it may be useful to identify the extent to which, under carefully controlled conditions, children with DS differ from developmentally-matched peers in terms of the frequency with which they engage with novel versus familiar (previously manipulated) objects, and the use and range of novel or familiar (previously produced) actions on objects. Beyond these previously uncharacterized dimensions, it may also be helpful to describe the extent to which strategies produced can be categorized by conventional play categories of sensory or functional acts on objects, and whether these interact with the use of novel objects or novel acts. In this study, patterns of performance on the dimension of object-related generativity in DS are compared to two mental-age matched comparison groups. The association between performance on an object-related generativity task and cognition and language measures is examined as well. 2. Method 2.1. Participants Participants were 52 children with Down syndrome, 21 nonverbal mental age (NVMA)- and chronological age-matched children with other developmental disabilities (DD), and 34 NVMA matched typically developing (TD) children (see Table 1 for demographic information). All three groups demonstrated a mean NVMA of approximately 4 years as measured by the Leiter Scales of Performance-Revised (Leiter-R; Roid & Miller, 1997). Groups showed similar distributions of gender and ethnicity, though maternal age was significantly higher for the DS group when compared to the TD group. The disability groups were close in chronological age, though the children in the DD group were marginally older. The TD group was significantly younger chronologically than the two disability groups. None of the children in the two disability groups met criteria for co-occurring autism spectrum disorder. 2.2. Procedures This study was conducted under the IRB approval at Colorado State University. Participants were a subset from a largerscale research study funded by U.S. Department of Education, National Institute of Disability and Rehabilitation Research (H133G100197) and the U.S. Department of Education, Institute of Educational Science, Special Education Research Grants (R324A110136). Participants were recruited through Rocky Mountain Down Syndrome Association, the Poudre School District in Fort Collins, CO, JFK Partners, a University Center of Excellence in Developmental Disabilities at the University of Colorado-Denver, and a regional genetics clinic in Decatur, GA. Parents of child participants provided written consent prior to completing any measures. Children provided assent for participating in developmental measures. Child participants attended 2–3 assessment visits. Parents completed questionnaires and observed laboratory assessment visits.
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Table 1 Demographic information by group.
Child gender (% male) Child Nonverbal MA (Leiter Brief IQ Age Equivalent in mos) Ethnicity European American Asian/Pacific Islander African American Other Mothers’ age (years) Mothers’ education (years)
X2 or F; (p)
Down syndrome
Other DD
TD
M or % SD
M or % SD
M or %SD
68.0% 47.75 (10.79)
52.2% 47.38 (14.18)
58.8% 49.29 (5.94)
1.84 (.40) .30 (.74)
81.3% 4.2%
78.3% 0.0%
90.6% 6.3%
7.23 (.51)
4.2% 8.3% 41.6 (6.19) 16.1 (2.32)
4.3% 17.4% 38.7 (5.87) 16.2 (3.01)
0.0% 3.1% 36.21 (4.12) 17.1 (2.10)
9.54 (.0001)DS > TD 1.97 (.14)
2.3. Measures The following measures were included: 1. Child developmental and family history: Parents were asked to provide information about their age, education level, income, and the child’s ethnicity. 2. Leiter-R: Experienced researchers administered the Leiter International Performance Scale-Revised Brief IQ composite (Leiter-R; Roid & Miller, 1997) to child participants in order to assess overall nonverbal mental age (MA). Four domains were administered: Figure Ground, Form Completion, Sequential Order, and Repeated Patterns. The Leiter-R was selected for nonverbal developmental assessment in DS because expressive language demands are minimized and responses are exclusively nonverbal. Examiners were trained, as per Leiter-R instructions, to minimize the receptive language load for each child during the assessment visits in order to minimize the confounding influence of pronounced language difficulties in DS. The Leiter-R was standardized on a national sample. Concurrent validity has been reported with the WISC-III Full Scale and Performance IQs (r = .85). High test-retest reliability has also been reported as well (r = upper .80s– .90s). Overall nonverbal mental age was estimated using the MA composite scores obtained for each participant. 3. Oral and Written Language Scales: The Oral and Written Language Scales (OWLS; Carrow-Woolfolk, 2008) is comprised of three scales: Listening Comprehension, Oral Expression, and Written Expression and is used as an individual assessment of oral and written language abilities from 3 years of age through 21 years of age. The OWLS has been standardized across all age groups in a nationwide sample of 1985 participants (Carrow-Woolfolk, 2008). The OWLS is reported to be valid and reliable with adequate test-retest reliability (ranging from r = .73 to .89) and high inter-rater reliability (r = .90–.99). We used the Listening Comprehension and Oral Expression subscales to assess receptive and expressive language abilities for each participant. The Listening Comprehension and Oral Expression subscales were combined to form a composite score of overall language functioning. The OWLS was administered to the DS and DD groups only. 4. Generativity Task: The Generativity task was administered during the first assessment visit. To maximize hand use and child engagement, children were seated in a therapeutic chair (Tripp Trapp chair) and the chair was adjusted to the child’s height so that they had adequate postural support. Children were then shown an opaque plastic box and asked if they would like to play with the items inside. They were told that the examiner had work to do, and that the child could play with the items in the box for a few minutes until the examiner was done working. This premise signaled to the child that the upcoming play time should be primarily individual in nature, and that the examiner would not be fully engaged as a social partner for this task. The examiner then placed all items from the opaque box were on the table top in front of the child. The items included: Pipe cleaners, wooden beads, plastic coins, rubbery bracelet bands, paper cups for baking, straws, miniature pompoms, colored popsicle sticks, foam sheets with holes punched around the perimeter, and lanyard strings. These items were selected because they had ambiguous play value and more divergent opportunities for object engagement. Throughout the administration of the task, the examiner remained seated at the table near the child, but attended to the papers that were in his/her file folder. When a child initiated a social interaction with the experimenter, the experimenter gave a quick, mildly positive response to the child, and then encouraged them to re-engage with the items while s/he finished her work. 2.4. Coding Participant object engagement was coded using Noldus Observer XT coding software. Coded behaviors included (1) type of engagement; and (2) novel use of an object. Type of engagement behaviors included functional or sensory acts on an object. Functional engagement was operationalized as visually guided or optimal manipulation of an object in a way that is appropriate given the object affordances (Belsky & Most, 1981). Examples of functional engagement include, but are not limited to: grouping like objects, using two like objects in the same way, and substituting like objects in the same scenario (Belsky & Most, 1981). Sensory engagement was operationalized as manipulating an object in a way that provides sensory
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Table 2 Descriptive statistics for object-related generativity dimensions (mean and SD). DS Freq. Freq. Freq. Freq. Freq. Freq. Freq. Freq.
of of of of of of of of
any acts on objects any familiar act (sensory or functional) any new act (sensory or functional) any acts on new objects new functional acts new functional play acts on new object familiar functional play on a new object holding
11.58 4.23 5.96 4.51 3.05 2.60 .45 5.04
(7.38) (5.96) (3.75) (2.61) (2.19) (2.06) (1.12) (4.14)
DD
TD
12.8 (4.77) 4.50 (3.76) 6.62 (2.76) 6.45 (3.25) 4.15 (3.17) 3.35 (2.70) .80 (2.01) 9.35 (9.05)
13.41 4.05 7.38 7.06 5.15 3.94 1.21 6.29
F(p) (4.74) (3.65) (3.17) (3.08) (3.17) (2.33) (2.21) (3.15)
.95 .06 1.81 8.89 6.18 3.65 2.54 5.10
(.39) (.95) (.17) (.0001); DS < DD; TD (.003); DS < TD (.029); DS < TD (.08) (.008) DS < DD
input or feedback. Examples of sensory engagement include but are not limited to: mouthing, squeezing, or banging an object. Novelty was captured in two different ways. Each object that was used was coded as a novel object or an object that had already been used in the generativity task (familiar object). Additionally, it was coded whether the participant engaged with the object in a novel way, or with the same action that had already been performed during the coded segment. If a participant picked up an object, but failed to engage with it before moving on to another object, a ‘‘holding only’’ code was used. Coded video segments were 2 min in length. Coders were trained to a minimum reliability of .70 and coded independently of one another. A random 30% subset of participants from each group was coded by both coders for reliability, with a mean kappa of .74. 3. Results 3.1. New vs. familiar objects All three groups demonstrated similar frequencies for total actions on objects (see Table 2 for descriptive information). However, children with DS showed significantly fewer acts on new objects overall (objects that they had not yet acted upon yet) than children in both comparison groups, F(2, 104) = 8.89, p = .0001. An examination of the magnitude of between group mean differences showed that children with DS demonstrated 30.1% fewer acts on new objects than children with DD, and 36.2% fewer acts on new objects than TD children. No meaningful differences were observed across groups when comparing rates of acts on familiar objects (objects a child had previously manipulated). 3.2. Types of actions on objects No meaningful between group differences were observed for total new acts (on new and familiar objects) and total familiar acts (on new and familiar objects). However, children with DS showed significantly fewer new functional acts on any objects (novel or previously used) than TD children, but not children with DD, F(2, 104) = 6.18, p = .003. Compared to children in the TD group, children with DS produced 40.6% fewer new functional acts on any objects, and 26.3% fewer new functional acts than the children in the DD group (the latter difference did not meet criteria for statistical significance). Children with DS produced a similar level of functional familiar acts on any object when compared to the other two groups. No statistically significant differences were observed when comparing the total frequency of sensory acts on objects (novel or familiar) across groups. When compared to children with DD, children with DS showed lower frequencies of holding objects (with no action on object performed), F(2, 104) = 5.10, p = .008. Overall, then, analyses suggested a pattern in the DS group that included fewer acts on new objects and fewer new functional acts. To explore the findings of fewer acts on new objects further, the coded dimensions of familiar functional acts on new objects (acts that had already been produced on another object) and new functional acts on new objects (novel acts that had not yet been produced previously on another object) were compared for the DS group and the MA-matched DD and TD comparison groups using MANOVA. Main effects were found for group [F(4, 208) = 2.92, p = .02; partial eta squared = .05; observed power = .78]. Scheffe post hoc tests demonstrated that the source of much of these differences resulted from the decreased frequency of new functional acts on new objects in the DS group. Children with DS demonstrated fewer instances of this behavior than children in both groups, though the lower frequency was statistically significant when compared to the TD group only. In other words, children with DS were less likely to use a novel functional act on a novel object (previously unused by them), especially when compared to TD children. 3.3. Correlates with nonverbal processing and language The dimension of frequency of total acts on new objects was correlated with nonverbal processing dimensions on the Leiter-R in the DS group, but not in the other two groups. In the DS group, statistically significant associations were observed between acts on new objects and Form Completion, r(50) = .48, p = .001 and Repeated Patterns, r (49) = .28, p = .05. In
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addition, the frequency of acts on new objects was significantly associated with Listening Comprehension scores on the OWLS in the DS group, r(50) = .31, p = .03, but not the other DD group. The dimension of frequency of new functional acts was associated with Form Completion, r(49) = .46, p = .001, in the DS group. Similar associations were observed for the DD group (r’s with Leiter-R, OWLS domains between .36 and .52), but not the TD group.
4. Discussion 4.1. Summary This study examined the dimension of object-related generativity in school-aged children with DS and two nonverbal MA-matched comparison groups. The dimension of object-related generativity was operationalized in the present study as the ability to flexibly produce a variety of behaviors and acts (functional and/or sensory) on a set of objects. This dimension may be of particular importance for early development in young children with DS, who have been shown to demonstrate impoverished early object exploration (de Campos et al., 2013; MacTurk et al., 1985) and poor object-related strategizing in toddlerhood (Fidler, Hepburn, et al., 2005; Fidler, Philofsky, et al., 2005). Early impoverished object-related behavior has been linked to less optimal outcomes developmentally in TD children (Bornsetin et al., 2013) and children with DS in particular (Fidler, Hepburn, et al., 2005; Fidler, Philofsky, et al., 2005). To date, however, there has been little in depth, descriptive examination of the nature of object-related actions in middle childhood in DS. All children in the present study engaged in a structured play session with a set of predetermined objects that were of ambiguous play value. Objects were specifically selected because they had no prescribed play schema associated with them. All play sessions were coded by naı¨ve coders for several dimensions: the frequency of acts on new versus familiar objects; the frequency of novel versus familiar acts on objects; and the use of functional versus sensory play behaviors. Several notable patterns were observed that are of potential utility for understanding goal-directed behavior in children with DS. First, children with DS showed a reduced frequency of actions on new (previously unmanipulated objects) when compared to the other two MA-matched groups. Children with DS were less likely act on objects that they had not yet manipulated, and produced 30–35% fewer acts on new objects when compared to both MA-matched groups. In contrast, all groups produced a similar number of acts on familiar (previously manipulated) objects. Furthermore, children with DS were found to demonstrate fewer novel functional acts (not previously demonstrated during the play session) on new objects when compared to the TD group. Follow up analyses demonstrated that children with DS showed fewer new functional acts on new objects that TD children. A similar pattern was observed when compared to the DD group, but the differences did not meet statistical significance. These findings have relevance for the developmental trajectory of individuals with DS throughout the first few decades of life. Growing work on the link between early object-related behavior and developmental outcomes in DS suggests that impoverished object-related generativity may have critical consequences for the development of adaptive skills, goaldirected behavior, and even language acquisition. Concurrent associations between the quality of object-related strategies and scores on the Vineland Adaptive Behavior Scales have been reported in toddlers with DS (Fidler, Hepburn, et al., 2005). Additional concurrent associations have been observed between object-related behavior and early nonverbal communication skills in DS (Fidler, Philofsky, et al., 2005). The present study sheds additional light on this area of study, as it suggests that there may be a specific atypical feature that contributes to these difficulties—the lack of engagement with novel objects, and the lack of production of novel functional acts on novel objects. In fact, the object-related strategizing required in the Fidler et al. studies involved the generation of novel functional strategies on an object (clear plexiglass box with one opening) in order to obtain a desired outcome. As such, previously reported difficulties with toddlers producing actions on objects are in in line with the specific atypical patterns observed in the present study—challenges with producing novel functional acts on new objects. 4.2. Implications These findings may be of additional developmental importance, as a growing body of research suggests that early objectrelated behavior facilitates the development of critical cognitive skills related to understanding the physical world (e.g. infant naı¨ve physics; Needham, Barrett, & Peterman, 2002; Sommerville, Woodward, & Needham, 2005). Enriched early object engagement experiences have been shown to facilitate the acquisition of certain cognitive milestones in early infancy (Needham et al., 2002). It is likely that similar patterns of association may be observed between object interest and nonverbal cognitive skill acquisition in children with DS as well. Furthermore, the implications of challenges in object-related generativity may have implications beyond cognitive development, as previous research has demonstrated that the number of objects acted upon during a play session moderates communication and language intervention outcomes for children with DS (Fey et al., 2013). The relationship between object interest and communication/language intervention outcomes is intriguing. Interest in objects in the natural environment is critical for the language acquisition process to take place, as a child must attend to object referents upon which to map new labels. A compromised level of interest and orientation toward objects would likely impede this process. Young TD children show a bias for mapping new labels on to objects that are novel (Horst, Samuelson, Kucker, & McMurray, 2011).
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Impoverished object interest and orientation may lead to engagement with a constricted set of objects a child’s environment, which may stage for fewer opportunities to acquire new labels. In seeking to further understand the nature of this association, it may be important to examine the role of object-related behavior and interest in the triadic communication context that facilitates language acquisition. Early language acquisition is strongly related to the ability of a young child to (triadically) coordinate her attention between a social partner and an object or event, particularly in the form of coordinated joint attention (Delgado et al., 2002; Markus, Mundy, Morales, Delgado, & Yale, 2000; Morales et al., 2000). While the intersubjective aspects of joint attention have been well-characterized (Trevarthen & Aitken, 2001), a perhaps underexplored component of joint attention involves the dimension of child interest in and orientation to objects—the content that ultimately drives a child to engage in triadic relating with a social partner. Close analysis of the facilitatory aspects of joint attention have focused on numerous dimensions, including executive processes (Van Hecke et al., 2012), caregiver temperament (Vaughan et al., 2003), and attention regulation (Delgado et al., 2002). However, Fey et al. (2013)’s findings may serve to highlight the importance of yet another contributor to the triadic context—interest in, motivational orientation toward, or awareness of the utility of objects. To the extent that object interest and motivation is critical for joint attention and triadic relating, it is possible that aspects of object-related interest and behavior will be observed to be related to neurocognitive and language-related outcomes throughout childhood in DS. In the present study, the relatively diminished number of actions on novel objects observed in the DS group relative to MA-matched comparison groups echoes the Fey et al. (2013) findings, wherein children who acted upon fewer objects showed more impoverished made fewer gains across a language/communication intervention trial. In fact, children with DS in the present study showed a strong association between the frequency of acts on novel objects and both cognitive and language outcomes. Together, these findings provide growing support for the pivotal nature of early object interest, engagement, and strategizing as a potential facilitator of developmental progress in the domains of cognition and language acquisition. 4.3. Limitations There are several limitations to the present study that may limit the generalizability of the reported findings. First, while the sample size for the DS group was substantial for studies of low-incidence neurogenetic disorders, there were fewer MAmatched children included in the two comparison groups. Despite extensive recruitment efforts, only a subset of comparison group participants who volunteered for the present study were found to be matched for MA with the children with DS. As such, analyses were conducted with uneven sample sizes. Future studies should aim to replicate the present findings with a larger sample of participants with DD. Second, the language development measure included in the present study, the OWLS, was not administered to the TD children. As a result, findings regarding the association between language outcomes and object-related generativity are not included in the present report. Subsequent work in this area should aim to identify whether participants with DS show patterns of association between object-related generativity and language outcomes that are similar or differ to TD children by administering language measures to a TD group as well. Overall, though, the findings presented in this study contribute to the growing knowledge base regarding the development of object-related behavior and developmental outcomes in DS. Fewer instances of engagement with novel objects and fewer novel functional acts on objects may, over time, have significant cognitive, language, and adaptation consequences for development in the population of individuals with DS during the first decade of life. 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Lee, N. R., Fidler, D. J., Blakely-Smith, A., Daunhauer, L., Robinson, C., & Hepburn, S. (2011). Parent-report of executive functioning in population-based sample of young children with Down syndrome. American Journal of Intellectual and Developmental Disabilities, 116, 290–304. http://dx.doi.org/10.1352/1944-7558116.4.290 MacTurk, R. H., Vietze, P. M., McCarthy, M. E., McQuiston, S., & Yarrow, L. J. (1985). The organization of exploratory behavior in Down syndrome and nondelayed infants. Child Development, 56, 573–581. Markus, J., Mundy, P., Morales, M., Delgado, C. E. F., & Yale, M. (2000). Individual differences in infant skills as predictors of child–caregiver joint attention and language. Social Development, 9, 302–315. http://dx.doi.org/10.1111/1467-9507.00127 Morales, M., Mundy, P., Delgado, C. E. F., Yale, M., Messinger, D., Neal, R., et al. (2000). Responding to joint attention across the 6-through 24-month age period and early language acquisition. Journal of Applied Developmental Psychology, 21, 283–298. Needham, A., Barrett, T., & Peterman, K. (2002). A pick-me-up for infants’ exploratory skills: Early simulated experiences reaching for objects using ‘sticky mittens’ enhances young infants’ object exploration skills. Infant Behavior and Development, 25, 279–295 Retrieved from: http://www.sciencedirect.com/science/ article/pii/S0163638302000978 Roid, G. H., & Miller, L. J. (1997). Leiter international performance scale-revised: Examiner’s manual. Wood Dale, IL: Stoelting. Sommerville, J. A., Woodward, A. L., & Needham, A. (2005). Action experience alters 3-month-old infants’ perception of others’ actions. Cognition, 96, B1–B11. http://dx.doi.org/10.1016/j.cognition.2004.07.004 Trevarthen, C., & Aitken, K. J. (2001). Infant intersubjectivity: Research, theory, and clinical applications. Journal of Child Psychology, 42, 3–48. http://dx.doi.org/ 10.1111/1469-7610.00701 Van Hecke, A. V., Mundy, A., Block, J. J., Delgado, C. E. F., Parlade, M. V., Pomares, Y. B., et al. (2012). Infant responding to joint attention, executive processes, and self-regulation in preschool children. Infant Behavior and Development, 35, 303–311. http://dx.doi.org/10.1016/j.infbeh.2011.12.001 Vaughan, A., Mundy, P., Block, J., Burnette, C., Delgado, C., Gomez, Y., et al. (2003). Child, caregiver, and temperament contributions to infant joint attention. Infancy, 4, 603–616. http://dx.doi.org/10.1207/S15327078IN0404_11
Contents lists available at ScienceDirect
Research in Developmental Disabilities
Object-related generativity in children with Down syndrome§ Deborah J. Fidler a,*, Elizabeth Will a, Lisa A. Daunhauer a, Brianne Gerlach-McDonald a, Jeannie Visootsak b a b
Human Development and Family Studies, Colorado State University, 1570 Campus Delivery, Fort Collins, CO 80523, USA Departments of Human Genetics and Pediatrics, Emory University, 2165 N. Decatur Rd., Decatur, GA 30033, USA
A R T I C L E I N F O
A B S T R A C T
Article history: Received 3 June 2014 Accepted 7 July 2014 Available online 6 September 2014
Children with Down syndrome (DS) show challenges in some aspects of goal-directed behavior when compared to developmentally matched children (Daunhauer et al., 2014; Lee et al., 2011), particularly in the area of goal-directed action on objects (Fidler et al., 2005a,b). In this study, we examined one aspect of goal-directed action on objects, objectrelated generativity, in school-aged children with DS (n = 52), a developmentally matched group of children with intellectual disability, but not Down syndrome (DD; n = 21), and a group of chronologically younger, but developmentally matched typically developing children (TD; n = 34). We administered the Leiter-R, the Oral and Written Language Scales (OWLS), and an Object-Related Generativity Task, which involved 2 min of unstructured play with a variety of objects that have divergent usages. Children with DS generated significantly fewer instances of initiating actions on new objects than children in both comparison groups, were less likely to produce novel functional action on any object (new or familiar) than TD children, and they showed fewer instances of novel functional object engagement with new objects overall than TD children. Frequency of acts on new objects in DS was associated with Leiter-R Form Completion and Repeated Patterns Raw Scores and OWLS Listening Comprehension Raw Scores. These findings contribute to the growing knowledge base regarding goal-directed behavior and self-regulation in individuals with Down syndrome. Implications for education and intervention are discussed. ß 2014 Elsevier Ltd. All rights reserved.
Keywords: Down syndrome Generativity Goal-directed behavior
1. Introduction Children with Down syndrome (DS) show relative challenges in aspects of goal-directed behavior when compared to developmentally-matched children (Daunhauer, Fidler, Lee, Will, & Hepburn, 2014; Fidler, Hepburn, Mankin, & Rogers, 2005; Fidler, Philofsky, Hepburn, & Rogers, 2005; Lee et al., 2011). In particular, the early development of goal-directed action on objects appears to be an area of impairment in infants with DS (de Campos, da Costa, Savelsbergh, & Rocha, 2013; MacTurk, Vietze, McCarthy, McQuiston, & Yarrow, 1985) and toddlers with DS (Fidler, Philofsky, et al., 2005) relative to overall developmental status. Two-year-old children with DS plan notably less optimal strategies than MA-matched children
§ The authors are grateful to the children and families who graciously contributed their time to this project. This study was funded by the U.S. Department of Education, National Institute of Disability and Rehabilitation Research (H133G100197) and the U.S. Department of Education, Institute of Educational Science, Special Education Research Grants (R324A110136). * Corresponding author. Tel.: +1 970491 7870. E-mail addresses: Deborah.fi[email protected] (D.J. Fidler), [email protected] (E. Will), [email protected] (L.A. Daunhauer), [email protected] (B. Gerlach-McDonald), [email protected] (J. Visootsak).
http://dx.doi.org/10.1016/j.ridd.2014.07.024 0891-4222/ß 2014 Elsevier Ltd. All rights reserved.
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on an object retrieval task that involves minimal motor demands (obtaining a desired object through the opening of a clear box; Fidler, Hepburn, et al., 2005). Similar findings have been observed when children with DS complete a comprehensive battery of object-related planning tasks (e.g. putting a necklace in a cup, putting coins in a coin bank; Fidler, Philofsky, et al., 2005). Understanding the complex pattern of challenge and competence in this area in DS may be of particular importance in that the ability to formulate actions on objects during early development has been found to predict later academic outcomes in typically developing children (Bornstein, Hahn, & Suwalsky, 2013). Effective planning with objects has also been concurrently linked to adaptive behavior outcomes and early instrumental communication in young children with DS (Fidler, Hepburn, et al., 2005). Recent evidence also suggests that object-related behavior may affect the ways that children with DS respond to early intervention. Fey, Yoder, Warren, and Bredin-Oja (2013) recently reported that the dimension of ‘object interest’ moderated intervention effects for preschoolers with DS in a rigorous communication/language focused early intervention program. Object interest was coded in the context of a Developmental Play Assessment where children were presented with sets of toys for 5 min segments, with minimal experimenter scaffolding offered. The specific dimension of object interest was operationalized as the number of different toys with which a child engaged in functional or symbolic play. A second dimension of ‘object knowledge’ was operationalized as the number of different play acts (functional or symbolic) that the child engaged in. Fey et al. (2013) reported that the object interest variable moderated treatment response in the areas of receptive and expressive vocabulary both at the end of the intervention, and after a 6 month post-intervention follow-up assessment. Despite the fact that children with DS have been shown to demonstrate challenges in goal-directed action on objects relative to developmentally matched peers, the dimension of object-related behavior in DS remains poorly characterized. There is some suggestion that during the first year of life, infants with DS specifically show impoverished reaching for and manual exploration of objects in comparison to TD infants (de Campos et al., 2013; MacTurk et al., 1985d). Toddlers with DS have also been shown to produce less optimal reaching strategies for goal-directed planning with objects (Fidler, Hepburn, et al., 2005; Fidler, Philofsky, et al., 2005). A more comprehensive account of the specific nature of object-related behavior in childhood in DS will shed light on this potentially important dimension, and will enable researchers to address this profile to enhance intervention and educational outcomes. To understand the specific presentation of object-related behavior outcomes in DS during childhood, it may be important to examine and describe performance on the dimension of object-related generativity. Object-related generativity is defined here as the ability to flexibly produce a variety of behaviors and strategies on a variety of novel objects. In particular, it may be useful to identify the extent to which, under carefully controlled conditions, children with DS differ from developmentally-matched peers in terms of the frequency with which they engage with novel versus familiar (previously manipulated) objects, and the use and range of novel or familiar (previously produced) actions on objects. Beyond these previously uncharacterized dimensions, it may also be helpful to describe the extent to which strategies produced can be categorized by conventional play categories of sensory or functional acts on objects, and whether these interact with the use of novel objects or novel acts. In this study, patterns of performance on the dimension of object-related generativity in DS are compared to two mental-age matched comparison groups. The association between performance on an object-related generativity task and cognition and language measures is examined as well. 2. Method 2.1. Participants Participants were 52 children with Down syndrome, 21 nonverbal mental age (NVMA)- and chronological age-matched children with other developmental disabilities (DD), and 34 NVMA matched typically developing (TD) children (see Table 1 for demographic information). All three groups demonstrated a mean NVMA of approximately 4 years as measured by the Leiter Scales of Performance-Revised (Leiter-R; Roid & Miller, 1997). Groups showed similar distributions of gender and ethnicity, though maternal age was significantly higher for the DS group when compared to the TD group. The disability groups were close in chronological age, though the children in the DD group were marginally older. The TD group was significantly younger chronologically than the two disability groups. None of the children in the two disability groups met criteria for co-occurring autism spectrum disorder. 2.2. Procedures This study was conducted under the IRB approval at Colorado State University. Participants were a subset from a largerscale research study funded by U.S. Department of Education, National Institute of Disability and Rehabilitation Research (H133G100197) and the U.S. Department of Education, Institute of Educational Science, Special Education Research Grants (R324A110136). Participants were recruited through Rocky Mountain Down Syndrome Association, the Poudre School District in Fort Collins, CO, JFK Partners, a University Center of Excellence in Developmental Disabilities at the University of Colorado-Denver, and a regional genetics clinic in Decatur, GA. Parents of child participants provided written consent prior to completing any measures. Children provided assent for participating in developmental measures. Child participants attended 2–3 assessment visits. Parents completed questionnaires and observed laboratory assessment visits.
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Table 1 Demographic information by group.
Child gender (% male) Child Nonverbal MA (Leiter Brief IQ Age Equivalent in mos) Ethnicity European American Asian/Pacific Islander African American Other Mothers’ age (years) Mothers’ education (years)
X2 or F; (p)
Down syndrome
Other DD
TD
M or % SD
M or % SD
M or %SD
68.0% 47.75 (10.79)
52.2% 47.38 (14.18)
58.8% 49.29 (5.94)
1.84 (.40) .30 (.74)
81.3% 4.2%
78.3% 0.0%
90.6% 6.3%
7.23 (.51)
4.2% 8.3% 41.6 (6.19) 16.1 (2.32)
4.3% 17.4% 38.7 (5.87) 16.2 (3.01)
0.0% 3.1% 36.21 (4.12) 17.1 (2.10)
9.54 (.0001)DS > TD 1.97 (.14)
2.3. Measures The following measures were included: 1. Child developmental and family history: Parents were asked to provide information about their age, education level, income, and the child’s ethnicity. 2. Leiter-R: Experienced researchers administered the Leiter International Performance Scale-Revised Brief IQ composite (Leiter-R; Roid & Miller, 1997) to child participants in order to assess overall nonverbal mental age (MA). Four domains were administered: Figure Ground, Form Completion, Sequential Order, and Repeated Patterns. The Leiter-R was selected for nonverbal developmental assessment in DS because expressive language demands are minimized and responses are exclusively nonverbal. Examiners were trained, as per Leiter-R instructions, to minimize the receptive language load for each child during the assessment visits in order to minimize the confounding influence of pronounced language difficulties in DS. The Leiter-R was standardized on a national sample. Concurrent validity has been reported with the WISC-III Full Scale and Performance IQs (r = .85). High test-retest reliability has also been reported as well (r = upper .80s– .90s). Overall nonverbal mental age was estimated using the MA composite scores obtained for each participant. 3. Oral and Written Language Scales: The Oral and Written Language Scales (OWLS; Carrow-Woolfolk, 2008) is comprised of three scales: Listening Comprehension, Oral Expression, and Written Expression and is used as an individual assessment of oral and written language abilities from 3 years of age through 21 years of age. The OWLS has been standardized across all age groups in a nationwide sample of 1985 participants (Carrow-Woolfolk, 2008). The OWLS is reported to be valid and reliable with adequate test-retest reliability (ranging from r = .73 to .89) and high inter-rater reliability (r = .90–.99). We used the Listening Comprehension and Oral Expression subscales to assess receptive and expressive language abilities for each participant. The Listening Comprehension and Oral Expression subscales were combined to form a composite score of overall language functioning. The OWLS was administered to the DS and DD groups only. 4. Generativity Task: The Generativity task was administered during the first assessment visit. To maximize hand use and child engagement, children were seated in a therapeutic chair (Tripp Trapp chair) and the chair was adjusted to the child’s height so that they had adequate postural support. Children were then shown an opaque plastic box and asked if they would like to play with the items inside. They were told that the examiner had work to do, and that the child could play with the items in the box for a few minutes until the examiner was done working. This premise signaled to the child that the upcoming play time should be primarily individual in nature, and that the examiner would not be fully engaged as a social partner for this task. The examiner then placed all items from the opaque box were on the table top in front of the child. The items included: Pipe cleaners, wooden beads, plastic coins, rubbery bracelet bands, paper cups for baking, straws, miniature pompoms, colored popsicle sticks, foam sheets with holes punched around the perimeter, and lanyard strings. These items were selected because they had ambiguous play value and more divergent opportunities for object engagement. Throughout the administration of the task, the examiner remained seated at the table near the child, but attended to the papers that were in his/her file folder. When a child initiated a social interaction with the experimenter, the experimenter gave a quick, mildly positive response to the child, and then encouraged them to re-engage with the items while s/he finished her work. 2.4. Coding Participant object engagement was coded using Noldus Observer XT coding software. Coded behaviors included (1) type of engagement; and (2) novel use of an object. Type of engagement behaviors included functional or sensory acts on an object. Functional engagement was operationalized as visually guided or optimal manipulation of an object in a way that is appropriate given the object affordances (Belsky & Most, 1981). Examples of functional engagement include, but are not limited to: grouping like objects, using two like objects in the same way, and substituting like objects in the same scenario (Belsky & Most, 1981). Sensory engagement was operationalized as manipulating an object in a way that provides sensory
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Table 2 Descriptive statistics for object-related generativity dimensions (mean and SD). DS Freq. Freq. Freq. Freq. Freq. Freq. Freq. Freq.
of of of of of of of of
any acts on objects any familiar act (sensory or functional) any new act (sensory or functional) any acts on new objects new functional acts new functional play acts on new object familiar functional play on a new object holding
11.58 4.23 5.96 4.51 3.05 2.60 .45 5.04
(7.38) (5.96) (3.75) (2.61) (2.19) (2.06) (1.12) (4.14)
DD
TD
12.8 (4.77) 4.50 (3.76) 6.62 (2.76) 6.45 (3.25) 4.15 (3.17) 3.35 (2.70) .80 (2.01) 9.35 (9.05)
13.41 4.05 7.38 7.06 5.15 3.94 1.21 6.29
F(p) (4.74) (3.65) (3.17) (3.08) (3.17) (2.33) (2.21) (3.15)
.95 .06 1.81 8.89 6.18 3.65 2.54 5.10
(.39) (.95) (.17) (.0001); DS < DD; TD (.003); DS < TD (.029); DS < TD (.08) (.008) DS < DD
input or feedback. Examples of sensory engagement include but are not limited to: mouthing, squeezing, or banging an object. Novelty was captured in two different ways. Each object that was used was coded as a novel object or an object that had already been used in the generativity task (familiar object). Additionally, it was coded whether the participant engaged with the object in a novel way, or with the same action that had already been performed during the coded segment. If a participant picked up an object, but failed to engage with it before moving on to another object, a ‘‘holding only’’ code was used. Coded video segments were 2 min in length. Coders were trained to a minimum reliability of .70 and coded independently of one another. A random 30% subset of participants from each group was coded by both coders for reliability, with a mean kappa of .74. 3. Results 3.1. New vs. familiar objects All three groups demonstrated similar frequencies for total actions on objects (see Table 2 for descriptive information). However, children with DS showed significantly fewer acts on new objects overall (objects that they had not yet acted upon yet) than children in both comparison groups, F(2, 104) = 8.89, p = .0001. An examination of the magnitude of between group mean differences showed that children with DS demonstrated 30.1% fewer acts on new objects than children with DD, and 36.2% fewer acts on new objects than TD children. No meaningful differences were observed across groups when comparing rates of acts on familiar objects (objects a child had previously manipulated). 3.2. Types of actions on objects No meaningful between group differences were observed for total new acts (on new and familiar objects) and total familiar acts (on new and familiar objects). However, children with DS showed significantly fewer new functional acts on any objects (novel or previously used) than TD children, but not children with DD, F(2, 104) = 6.18, p = .003. Compared to children in the TD group, children with DS produced 40.6% fewer new functional acts on any objects, and 26.3% fewer new functional acts than the children in the DD group (the latter difference did not meet criteria for statistical significance). Children with DS produced a similar level of functional familiar acts on any object when compared to the other two groups. No statistically significant differences were observed when comparing the total frequency of sensory acts on objects (novel or familiar) across groups. When compared to children with DD, children with DS showed lower frequencies of holding objects (with no action on object performed), F(2, 104) = 5.10, p = .008. Overall, then, analyses suggested a pattern in the DS group that included fewer acts on new objects and fewer new functional acts. To explore the findings of fewer acts on new objects further, the coded dimensions of familiar functional acts on new objects (acts that had already been produced on another object) and new functional acts on new objects (novel acts that had not yet been produced previously on another object) were compared for the DS group and the MA-matched DD and TD comparison groups using MANOVA. Main effects were found for group [F(4, 208) = 2.92, p = .02; partial eta squared = .05; observed power = .78]. Scheffe post hoc tests demonstrated that the source of much of these differences resulted from the decreased frequency of new functional acts on new objects in the DS group. Children with DS demonstrated fewer instances of this behavior than children in both groups, though the lower frequency was statistically significant when compared to the TD group only. In other words, children with DS were less likely to use a novel functional act on a novel object (previously unused by them), especially when compared to TD children. 3.3. Correlates with nonverbal processing and language The dimension of frequency of total acts on new objects was correlated with nonverbal processing dimensions on the Leiter-R in the DS group, but not in the other two groups. In the DS group, statistically significant associations were observed between acts on new objects and Form Completion, r(50) = .48, p = .001 and Repeated Patterns, r (49) = .28, p = .05. In
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addition, the frequency of acts on new objects was significantly associated with Listening Comprehension scores on the OWLS in the DS group, r(50) = .31, p = .03, but not the other DD group. The dimension of frequency of new functional acts was associated with Form Completion, r(49) = .46, p = .001, in the DS group. Similar associations were observed for the DD group (r’s with Leiter-R, OWLS domains between .36 and .52), but not the TD group.
4. Discussion 4.1. Summary This study examined the dimension of object-related generativity in school-aged children with DS and two nonverbal MA-matched comparison groups. The dimension of object-related generativity was operationalized in the present study as the ability to flexibly produce a variety of behaviors and acts (functional and/or sensory) on a set of objects. This dimension may be of particular importance for early development in young children with DS, who have been shown to demonstrate impoverished early object exploration (de Campos et al., 2013; MacTurk et al., 1985) and poor object-related strategizing in toddlerhood (Fidler, Hepburn, et al., 2005; Fidler, Philofsky, et al., 2005). Early impoverished object-related behavior has been linked to less optimal outcomes developmentally in TD children (Bornsetin et al., 2013) and children with DS in particular (Fidler, Hepburn, et al., 2005; Fidler, Philofsky, et al., 2005). To date, however, there has been little in depth, descriptive examination of the nature of object-related actions in middle childhood in DS. All children in the present study engaged in a structured play session with a set of predetermined objects that were of ambiguous play value. Objects were specifically selected because they had no prescribed play schema associated with them. All play sessions were coded by naı¨ve coders for several dimensions: the frequency of acts on new versus familiar objects; the frequency of novel versus familiar acts on objects; and the use of functional versus sensory play behaviors. Several notable patterns were observed that are of potential utility for understanding goal-directed behavior in children with DS. First, children with DS showed a reduced frequency of actions on new (previously unmanipulated objects) when compared to the other two MA-matched groups. Children with DS were less likely act on objects that they had not yet manipulated, and produced 30–35% fewer acts on new objects when compared to both MA-matched groups. In contrast, all groups produced a similar number of acts on familiar (previously manipulated) objects. Furthermore, children with DS were found to demonstrate fewer novel functional acts (not previously demonstrated during the play session) on new objects when compared to the TD group. Follow up analyses demonstrated that children with DS showed fewer new functional acts on new objects that TD children. A similar pattern was observed when compared to the DD group, but the differences did not meet statistical significance. These findings have relevance for the developmental trajectory of individuals with DS throughout the first few decades of life. Growing work on the link between early object-related behavior and developmental outcomes in DS suggests that impoverished object-related generativity may have critical consequences for the development of adaptive skills, goaldirected behavior, and even language acquisition. Concurrent associations between the quality of object-related strategies and scores on the Vineland Adaptive Behavior Scales have been reported in toddlers with DS (Fidler, Hepburn, et al., 2005). Additional concurrent associations have been observed between object-related behavior and early nonverbal communication skills in DS (Fidler, Philofsky, et al., 2005). The present study sheds additional light on this area of study, as it suggests that there may be a specific atypical feature that contributes to these difficulties—the lack of engagement with novel objects, and the lack of production of novel functional acts on novel objects. In fact, the object-related strategizing required in the Fidler et al. studies involved the generation of novel functional strategies on an object (clear plexiglass box with one opening) in order to obtain a desired outcome. As such, previously reported difficulties with toddlers producing actions on objects are in in line with the specific atypical patterns observed in the present study—challenges with producing novel functional acts on new objects. 4.2. Implications These findings may be of additional developmental importance, as a growing body of research suggests that early objectrelated behavior facilitates the development of critical cognitive skills related to understanding the physical world (e.g. infant naı¨ve physics; Needham, Barrett, & Peterman, 2002; Sommerville, Woodward, & Needham, 2005). Enriched early object engagement experiences have been shown to facilitate the acquisition of certain cognitive milestones in early infancy (Needham et al., 2002). It is likely that similar patterns of association may be observed between object interest and nonverbal cognitive skill acquisition in children with DS as well. Furthermore, the implications of challenges in object-related generativity may have implications beyond cognitive development, as previous research has demonstrated that the number of objects acted upon during a play session moderates communication and language intervention outcomes for children with DS (Fey et al., 2013). The relationship between object interest and communication/language intervention outcomes is intriguing. Interest in objects in the natural environment is critical for the language acquisition process to take place, as a child must attend to object referents upon which to map new labels. A compromised level of interest and orientation toward objects would likely impede this process. Young TD children show a bias for mapping new labels on to objects that are novel (Horst, Samuelson, Kucker, & McMurray, 2011).
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Impoverished object interest and orientation may lead to engagement with a constricted set of objects a child’s environment, which may stage for fewer opportunities to acquire new labels. In seeking to further understand the nature of this association, it may be important to examine the role of object-related behavior and interest in the triadic communication context that facilitates language acquisition. Early language acquisition is strongly related to the ability of a young child to (triadically) coordinate her attention between a social partner and an object or event, particularly in the form of coordinated joint attention (Delgado et al., 2002; Markus, Mundy, Morales, Delgado, & Yale, 2000; Morales et al., 2000). While the intersubjective aspects of joint attention have been well-characterized (Trevarthen & Aitken, 2001), a perhaps underexplored component of joint attention involves the dimension of child interest in and orientation to objects—the content that ultimately drives a child to engage in triadic relating with a social partner. Close analysis of the facilitatory aspects of joint attention have focused on numerous dimensions, including executive processes (Van Hecke et al., 2012), caregiver temperament (Vaughan et al., 2003), and attention regulation (Delgado et al., 2002). However, Fey et al. (2013)’s findings may serve to highlight the importance of yet another contributor to the triadic context—interest in, motivational orientation toward, or awareness of the utility of objects. To the extent that object interest and motivation is critical for joint attention and triadic relating, it is possible that aspects of object-related interest and behavior will be observed to be related to neurocognitive and language-related outcomes throughout childhood in DS. In the present study, the relatively diminished number of actions on novel objects observed in the DS group relative to MA-matched comparison groups echoes the Fey et al. (2013) findings, wherein children who acted upon fewer objects showed more impoverished made fewer gains across a language/communication intervention trial. In fact, children with DS in the present study showed a strong association between the frequency of acts on novel objects and both cognitive and language outcomes. Together, these findings provide growing support for the pivotal nature of early object interest, engagement, and strategizing as a potential facilitator of developmental progress in the domains of cognition and language acquisition. 4.3. Limitations There are several limitations to the present study that may limit the generalizability of the reported findings. First, while the sample size for the DS group was substantial for studies of low-incidence neurogenetic disorders, there were fewer MAmatched children included in the two comparison groups. Despite extensive recruitment efforts, only a subset of comparison group participants who volunteered for the present study were found to be matched for MA with the children with DS. As such, analyses were conducted with uneven sample sizes. Future studies should aim to replicate the present findings with a larger sample of participants with DD. Second, the language development measure included in the present study, the OWLS, was not administered to the TD children. As a result, findings regarding the association between language outcomes and object-related generativity are not included in the present report. Subsequent work in this area should aim to identify whether participants with DS show patterns of association between object-related generativity and language outcomes that are similar or differ to TD children by administering language measures to a TD group as well. Overall, though, the findings presented in this study contribute to the growing knowledge base regarding the development of object-related behavior and developmental outcomes in DS. Fewer instances of engagement with novel objects and fewer novel functional acts on objects may, over time, have significant cognitive, language, and adaptation consequences for development in the population of individuals with DS during the first decade of life. 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