Baby Signs: What the Meta-Analyses Actually Say

Lead

"Communicate before words arrive." "Higher IQ." "Accelerated language development." The marketing language surrounding baby signs — simplified gesture systems taught to preverbal infants — has grown considerably more ambitious over the past two decades.

The lived experience of many families who try it is warmly positive. The "milk" sign making morning routines a little easier to read; the "more" sign clarifying how much more puree is wanted. These small functional wins are real.

The problem is a large gap between these modest practical successes and the sweeping claims about accelerated language development and elevated intelligence. This article is not an argument against baby signs, nor a promotion of them. It is an attempt to set out, as steadily as possible, what the meta-analyses and systematic reviews say — and what they deliberately do not say.

Where It Began: Goodwyn and Acredolo

The academic case for baby signs was introduced by Goodwyn and Acredolo at the University of California. Their study published in the Journal of Nonverbal Behavior in 2000 was a small RCT — 103 infants at 11 months divided into three groups — that found symbolic gesturing (simplified signs for infants) did not impede language development and might slightly facilitate it [1].

This paper became the foundation most often cited by the commercial baby sign industry. The research was broadly popularized — a scene in the film Meet the Fockers in which Robert De Niro teaches his grandchild signs is often connected to wider awareness of Acredolo and colleagues' work.

Reading the original paper directly, however, a careful hedging is apparent throughout. The sample was small, effect sizes were modest, and the conclusion was explicitly limited to: symbolic gesturing does not appear to impede verbal development and might facilitate it [1]. The distance between "might facilitate" and "does facilitate" is substantial in research terms. In the commercial retelling, that distance was often collapsed.

A Cooler Picture from the Systematic Reviews

After Goodwyn and Acredolo, several studies tried to replicate and extend the findings, with inconsistent results. In 2005, Johnston, Durieux-Smith, and Bloom published a systematic review of 17 studies on baby sign in the journal First Language [2]. Their conclusion was unambiguous:

"There is insufficient scientific evidence at this time to support the claim that baby signing accelerates language development in typically developing children."

The methodological problems they identified were:

• Small sample sizes
• Inadequate randomization or weak control group design
• Unequal levels of caregiver-child verbal interaction between the signing group and the control group — making it difficult to know whether observed effects came from the signs themselves or from the increased time and attention that signing practice involved

"Not shown to work" is different from "shown not to work" — that distinction matters for how to read this literature.

Kirk and colleagues published the first large-scale RCT in this space in Child Development in 2013 [3]. Forty mother-infant pairs were tracked from 8 to 20 months across three conditions: a symbolic gesture training group, a verbal labeling training group, and a control group. The result:

"No significant differences in language development were found between the baby sign group and either the control or verbal labeling groups."

The intervention had no language-promoting effect in this design.

In 2014, Fitzpatrick and colleagues updated the systematic review in First Language, covering 10 studies published between 1990 and 2013. Their summary: "The evidence that baby signs improve communication development is not clear; equally, there is no evidence that they impede normal language acquisition" [4].

The current state of the field, as represented by these reviews, is: no clear acceleration of language development has been demonstrated. That is the most accurate single-sentence summary.

What Does Change: Caregiver Responsiveness

Ending there would leave a misleading impression. Baby signs being neutral on language outcomes does not mean they are neutral on everything.

Kirk and colleagues' RCT found that while language development showed no between-group difference, mothers in the symbolic gesture group showed higher responsiveness to their infants' non-verbal signals, and were more likely to promote infant autonomy, compared to control mothers [3]. The process of learning to sign appeared to change how parents watched and responded to their children — independent of any effect the signs themselves may have had on infant language.

Doherty-Sneddon, in a commentary on the gestural communication literature, proposed a reframing: baby signs may work not through the signs themselves but by making parents more attentive observers of their children's communicative attempts [5]. "A magic tool that accelerates language" gives way to "a medium through which caregiver responsiveness increases." The shift is modest in phrasing and significant in implication.

This interpretation is consistent with Kirk and colleagues' findings [3], and it changes the practical question. Instead of "will this make my child talk sooner?", the more relevant question becomes "does this practice make our interactions richer right now?"

A Verdict Without a Verdict

Pulling the evidence together, here is what it supports with reasonable confidence:

• Accelerating language development: no strong evidence [2,3,4]
• Impeding language development: no evidence [4]
• Increasing caregiver responsiveness: tentatively supported [3,5]
• Giving a preverbal child a functional way to express intentions: this is a practical observation rather than a research finding, but it is real

Baby signs are better understood as a form of play that may enrich the quality of present interactions than as an investment in future cognitive performance. If the commercial programs feel too expensive or too systematic, starting with three to five signs from a freely available list is well-matched to how strong the underlying evidence actually is.

One consideration when deciding whether to try it: the mechanism Kirk and colleagues pointed to — increased parental attention and responsiveness — depends on the caregiver finding the practice genuinely engaging [3]. If signing practice feels like a chore, the mechanism that makes it worth doing stops first. Whether it is enjoyable for the parent matters more than whether the child performs the signs correctly.

A Different Kind of Observation

One thing worth noting outside the research debate: the first time a child uses a sign intentionally — the "milk" sign appearing unprompted at 7 months, the "more" gesture offered mid-meal — is a small milestone. It will not appear in any standard developmental chart. It is particular to that family.

An app like Memori, which logs observations in chronological order by age, is well suited to catching these family-specific moments. Tracking the baby sign milestones that matter to a specific household — rather than the generic ones in a handbook — tends to produce records that feel worth looking back at years later. That holds whether baby signs are part of the routine or not.

Summary

The commercial claim that baby signs accelerate language development lacks sufficient evidence from the current research base [2,3,4]. The claim that they harm language development also lacks evidence [4]. What tentative support exists suggests that the practice may increase caregiver attentiveness and responsiveness — which is a different and more modest benefit [3,5].

The conclusion is genuinely permissive: you can try it, or you can skip it. The deciding factor should not be projected cognitive returns but whether it makes the daily back-and-forth more enjoyable right now. That is about as much as the evidence warrants — and that is enough.

References

1. Goodwyn SW, Acredolo LP, Brown CA. Impact of Symbolic Gesturing on Early Language Development. J Nonverbal Behav. 2000;24(2):81–103. doi:10.1023/A:1006653828895.
2. Johnston JC, Durieux-Smith A, Bloom K. Teaching gestural signs to infants to advance child development: A review of the evidence. First Language. 2005;25(2):235–251. doi:10.1177/0142723705050340.
3. Kirk E, Howlett N, Pine KJ, Fletcher BC. To sign or not to sign? The impact of encouraging infants to gesture on infant language and maternal mind-mindedness. Child Dev. 2013;84(2):574–590. doi:10.1111/j.1467-8624.2012.01874.x. PMID: 23033858.
4. Fitzpatrick EM, Thibert J, Grandpierre V, Johnston JC. 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. First Language. 2014;34(6):486–509. doi:10.1177/0142723714562864.
5. Howard LE, Doherty-Sneddon G. How HANDy are baby signs? A commentary on a systematic review of the impact of gestural communication on typically developing, hearing infants under the age of 36 months. First Language. 2014;34(6):510–515. doi:10.1177/0142723714561342.