Systematic Review: Baby Signs Impact on Infant Communication

First Language
2014, Vol. 34(6) 486 –509
© The Author(s) 2014
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DOI: 10.1177/0142723714562864
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FIRST
LANGUAGE
How HANDy are baby signs?
A systematic review of
the impact of gestural
communication on typically
developing, hearing infants
under the age of 36 months
Elizabeth M. Fitzpatrick
Faculty of Health Sciences, University of Ottawa, Canada; Children’s Hospital of Eastern Ontario Research
Institute, Canada
Jonelle Thibert
Private practice speech-language pathologist, Canada
Viviane Grandpierre
Faculty of Health Sciences, University of Ottawa, Canada; Children’s Hospital of Eastern Ontario Research
Institute, Canada
J. Cyne Johnston
Alberta Health Services, Canada; University of Calgary, Canada
Abstract
Baby sign language is advocated to improve children’s communication development.
However, the evidence to support the advantages of baby sign has been inconclusive.
A systematic review was undertaken to summarize and appraise the research related
to the effectiveness of symbolic gestures for typically developing, hearing infants with
hearing parents. Eight electronic databases, reference lists, and websites were searched
for relevant studies published from January 1990 to February 2013. Studies were
included if they involved typically developing hearing children who were exposed to
Corresponding author:
Elizabeth M. Fitzpatrick, Faculty of Health Sciences, University of Ottawa, 451 Smyth Road, Ottawa, ON
K1H 8M5, Canada.
Email: [email protected]
562864FLA0010.1177/0142723714562864First LanguageFitzpatrick et al.
research-article2014
Article

Fitzpatrick et al. 487
symbolic gestures before age 36 months. Of 1902 identified citations, 10 reports met
the inclusion criteria. This review shows that the effectiveness of baby sign in improving
communication development remains unclear. However, no evidence was identified to
suggest that using baby sign interferes with typical child development.
Keywords
Baby sign, development, children, gestures, infants, language, review
Introduction
Parents want the best for their children and are interested in programs and products that
support and promote early child development. Language acquisition is an exciting and
crucial phase in children’s development as they learn to interact, communicate, and
transmit their thoughts and desires. Typically, a child’s first words appear at approxi-
mately 12 months of age, while word combinations are observed during the second year
of life (Jusczyk, 1997). However, communication intents can be evident as early as 6
months. A gap between a child’s desire to communicate and their ability to do so by using
spoken words is well documented (Bates & Dick, 2002; Iverson & Goldin-Meadow,
2005; Rowe & Goldin-Meadow, 2009).
Global motor development occurs much earlier than oral language and the first gesture
(generally pointing) occurs at approximately 8–10 months (Vallotton, 2008). In fact, ges-
tures are inextricably connected to language development (Acredolo, Goodwyn, Horobin,
& Emmons, 1999; Bates & Dick, 2002). For example, studies have shown an association
between gesture use in early childhood and later verbal vocabulary size as well as between
gesture–speech combined utterances, the age of two-word utterance production, and later
sentence complexity (Iverson & Goldin-Meadow, 2005; Iverson, Capirci, Volterra, &
Goldin-Meadow, 2008; Rowe & Goldin-Meadow, 2009). Recent research continues to
lend support to the benefits of gestures in terms of facilitating parent–child interaction and
early communication development. For example, Olson and Masur (2013) found that
mothers responded more frequently and used more verbal responses when infants’ com-
municative attempts involved gestures. Parents’ positive responses to their infants’ gestures
have been shown to increase infants’ attempts at communication through both gestures and
vocalizations (Miller & Lossia, 2013). These studies suggest that infant gesture use and
parents’ subsequent responsiveness lead to joint-attention opportunities, which have long
been linked with positive language outcomes (Tomasello & Farrar, 1986).
Two types of early child gestures are commonly identified: deictic gestures and sym-
bolic or representational gestures (Capirci, Iverson, Pizzuto, & Volterra, 1996). Deictic
gestures, such as pointing and reaching, are among the first gestures produced by chil-
dren (Locke, 2007). Symbolic gestures are generally defined as hand movements that
take on a form or function of items and can stand alone in much the same way as words.
They are representative of objects and actions and can be used to label, describe, and
request (Goodwyn & Acredolo, 1998). They can also be observed used in combination
with spoken words to form short utterances (Capirci et al., 1996). An example of a

488 First Language 34(6)
symbolic gesture is the motion of hands flapping to represent ‘bird’. Symbolic gestures,
as considered in this review, are also often referred to as baby signs when caregivers
deliberately and specifically provide enhanced gesture training to infants to promote
early communication development. These baby signs differ from established sign lan-
guages used by individuals who are deaf in that they are not intended to be used as a
language or as a replacement for oral vocabulary but rather only as a symbolic support to
spoken language in early childhood.
Due to the early development of gross motor skills, the use and teaching of symbolic
gestures to infants before their ability to communicate orally, often referred to as baby
sign language, has grown in popularity in the media, on television, on the Internet, in
daycare programs as well as in clinical settings. In recent years, a wide variety of pro-
grams, books, videos, and classes of baby signs have been made available to parents and
caregivers (Doherty-Sneddon, 2008; Nelson, White, & Grewe, 2012). In addition to
facilitating early communication, these products and websites claim numerous benefits
such as greater understanding of the child’s needs, reduced frustration and stress, fewer
tears and tantrums, better parent–child bonding, higher self-esteem, improved receptive
and expressive language abilities, and enhanced cognitive development (Johnston,
Durieux-Smith, & Bloom, 2005; Nelson et al., 2012; Paling, 2007).
Furthermore, in 2011, the American Academy of Pediatrics (AAP) recognized that
baby sign language helps to improve communication (American Academy of Pediatrics,
2011). Despite this type of endorsement and the general support for baby signs in pro-
moting language, there has been relatively little scientific evidence to support these
claims. To date, three reviews have reported findings related to the benefits of teaching
baby signs to young children with normal hearing. A systematic review in 2005 (Johnston
et al., 2005) and a 2007 critical review (Paling, 2007) both reported inconsistent and
equivocal results between studies. The Johnston et al. (2005) review, which included 17
reports published between 1980 and 2002, evaluated the effectiveness of signing in stud-
ies of children of parents with normal hearing (n = 5) and also included studies of chil-
dren who were exposed to signing because their parents had hearing loss (n = 12).
Paling’s (2007) critical review, which applied narrower inclusion criteria, reported on
three studies published from 1980 to 2005, one of which was the Johnston et al. (2005)
systematic review. These reviews both concluded that there was insufficient evidence to
support the advancement in language development and that the included studies had seri-
ous methodological weaknesses. More recently, Nelson et al. (2012) conducted a review
of 33 baby sign websites that promoted improved development through sign language,
and argued that while these websites cite a wealth of reports, they offer limited informa-
tion to support the benefits claimed. Of the cumulated 82 pieces of evidence cited as
supporting research, only eight consisted of empirical research studies, while 90% of the
citations were opinion articles.
Given the continued interest and support for baby sign, we undertook a systematic
review to evaluate the current literature by identifying strengths, weaknesses, and gaps.
This information will permit knowledge users such as early childhood educators, clini-
cians, and parents to make informed decisions about the use of and emphasis to place on
baby sign language with typically developing children. The main objective of this project
was to update the existing available information by systematically reviewing, evaluating,

Fitzpatrick et al. 489
and synthesizing published literature on baby sign language intervention and its impact
on developmental outcomes, particularly in language development as well as parent–
child interaction and other related aspects of parent–child well-being. The specific
research question addressed in this systematic review was: Does baby sign language help
promote language, social, cognitive development, parent/caregiver–child interactions or
other aspects of quality of life in typically developing hearing infants under the age of 36
months?
Methods
Search strategy
A search strategy was designed with the assistance of two library information specialists
with expertise in systematic reviews. These specialists helped define the terminology
and guided and refined the strategy for the eight included electronic databases. The
search strategy was developed in MEDLINE and then adapted for the other databases:
CINAHL, Cochrane Library (Wiley), ComDisDome, EMBASE, ERIC, LLBA, and
PsycINFO. Search terms included: sign language, baby sign, symbolic gesture, gestural
communication, children, infant, preschool, hearing, child development, and language
development. The search was restricted to the pediatric age group and the start date was
limited to 1990; databases were searched for articles published from January 1990 to
February 2013. Electronic searching of databases was followed by hand searching from
reference lists of studies that met the inclusion criteria, review articles, and websites in
order to collect relevant articles in English or French. Website searching involved a
Google Scholar search using the keywords: baby sign language, signs, symbolic ges-
tures, gestural language, cognitive, social child development.
Eligibility criteria
Population. Studies of children with typical development and normal hearing who were
exposed to baby sign language in early childhood (before age 36 months) were eligible
for inclusion. The hearing status of parents was important in order to exclude research
with children using gestures or signs as a first or second language. Thus, children with
hearing loss, and children born to deaf parents, and children with atypical development
were not considered eligible for inclusion, as this was not the focus of this review.
Intervention. For the purpose of this review, the definition of baby signs was viewed as
symbolic gestures representing objects (i.e. arm flapping for bird), actions (i.e. thumb to
mouth for ‘drink’) or states (i.e. drag index finger down cheek for ‘sad’) that were rele-
vant to children and that were taught to infants through adult modeling. These are the
types of signs used in the commercially available baby sign programs. Therefore, studies
related to deictic gestures (e.g. pointing) were not considered appropriate for this review.
Any intervention meeting the description of baby signs using terms such as baby sign
language, signs, symbolic gestures, and gestural language as well as any articles using
commercial programs of signing with children were considered eligible for inclusion.

490 First Language 34(6)
Comparison. We originally sought to retrieve studies that included a comparison or con-
trol group of children with typical development and normal hearing who did not receive
baby sign language or other symbolic gesture intervention. However, given the limited
number of studies, we also included studies of children exposed to baby sign language
without a comparison group.
Outcomes. The primary outcomes of interest were measures of the effectiveness of baby
sign on language acquisition including receptive and expressive language. Receptive
language refers to the child’s understanding of language including both words and ges-
tures, while expressive language involves language output or production. Studies involv-
ing social and cognitive development as well as parent–child interaction, parent
responsiveness, and any other relevant child behavior or parent-related outcomes
reported were also included.
Study design. Study designs included randomized controlled trials, prospective cohort,
retrospective cohort, cross-sectional studies, and case series of greater or equal to five
participants. The review was restricted to primary studies, therefore reviews, letters, edi-
torials, and commentaries were excluded.
Timing. Given that there were few studies prior to 1990 and that these early studies were
reported in previous reviews (Johnston et al., 2005; Nelson et al., 2012; Paling, 2007),
the time period for this review was limited to studies conducted after 1990.
Study selection
The search results were downloaded into a RefWorks database where duplicates were
removed. Inclusion and exclusion criteria were then applied independently by two inves-
tigators (JT and VG) at two levels of screening, first title and abstract and then full-text.
Calibration exercises to ensure consistent interpretation of the inclusion criteria were
carried out at each stage. Two authors reviewed all titles and abstracts (if available).
Next, using a priori inclusion criteria, a detailed relevance assessment of the complete
document was carried out on the full-text of all publications judged to be potentially
eligible in order to select the final reports for data abstraction. Disagreements and uncer-
tainties were resolved through consensus or through consultation with a third team mem-
ber, one of the study authors (EF).
Data abstraction
A data extraction sheet was developed for the study to capture general study characteris-
tics and details of interventions. Details were abstracted related to country of origin,
study design, study population, comparison group(s), intervention, and outcomes for
each included study. Two authors (JT and EF) independently abstracted data for one of
the included articles to clarify and discuss any discrepancies in interpretation. One author
(JT) completed data extraction sheets for the remaining articles and a second author
(VG) verified all entries. Any discrepancies were verified by a third author (EF). Due to