Baby signs boost IQ by 12 points

Fri Oct 19 15:36:46 UTC 2007

I have enjoyed the recent discussion about baby signs and wish to 
underscore the point of Adele Abrahamsen's message:  that the debate over 
IQ effects overlooks the really important aspects of Acredolo and Goodwyn's 
work, which spoke more to the debate on whether early signing and/or 
gesturing in oral/aural children would somehow impede their spoken language 
development.

I organized and edited a special issue on children and gesture for the 
Journal of Nonverbal Behavior, published in 2000 (summer issue, vol. 
24).  The Acredolo and Goodwyn team have two papers in that issue, the most 
pertinent to the discussion here an experimental design (co-authored by 
Catherine Brown) of 11-month-old infants randomly assigned to three 
different conditions of varying levels of parental (signed and spoken) input.

An excerpt from their Discussion:  "The results...particularly the 
comparisons between the Sign Training group and the Non-intervention 
Control group, strongly support the hypothesis that symbolic gesturing 
facilitates the early stages of verbal language development.... infants who 
augmented their fledgling vocabularies with symbolic gestures outperformed 
those who did not.  The fact that no such advantage was found for the 
infants in the Verbal Training group provides reassuring evidence that the 
superior performance of the ST infants was not simply a function of their 
families being involved in a language-centered intervention program.  The 
explanation seems to lie instead within the gesturing experience itself."

I have no dog in this fight, not even a puppy in the scuffle, but I write 
simply to encourage interested parties to read this fine paper and return 
to, as Adele suggested, the real points of their work.  In this 2000 paper 
there is no measurement or discussion of IQ but the measurement of many 
language indices longitudinally at 15, 19, 24, 30, and 36 months.  (Would 
that our field featured more longitudinal and experimental designs, of any 
developmental phenomena!)

Chris Boyatzis

At 10:56 PM 10/18/2007, Adele Abrahamsen wrote:
>The claim of later IQ effects unfortunately distracts from the most
>important impact of Acredolo and Goodwyn's work.
>
>It was long assumed that manual symbols would compete, and hence
>interfere, with spoken words.  In my own research on what is now called
>baby sign, initially I could offer potential participants nothing more
>than indirect evidence and reasoning to the contrary. So I was delighted
>when Goodwyn and Acredolo (1993) provided compelling direct evidence that
>baby signs do not interfere with acquisition of spoken words. Moreover,
>regardless of whether baby signs facilitate spoken words, clearly a baby
>who acquires them has more symbols available for use. (E.g., a reanalysis
>of G&A's data in Abrahamsen 2000 showed a median of 5.8 gestures when the
>median number of words was 5.9; for those toddlers with no overlap, that
>doubled the number of meanings that could be expressed through symbols at
>that time.) There also is a hard-to-predict subgroup of toddlers for whom
>baby signs carry much more than half the communicative burden for several
>months, which would seem to be advantageous.
>
>It is much more challenging to determine the extent to which, if at all,
>baby signing results in facilitation of spoken language or general
>development. To their credit Acredolo and Goodwyn included longitudinal
>comparison groups in their design, but as Brian and Kathy noted, the
>results raised more questions than they answered. Ideally someone would
>step up and do a replication study with a larger number of randomly
>assigned or closely-matched participants.
>
>Meanwhile, it would be sensible to base the decision to enhance gestural
>input to a baby on practical considerations (e.g., is there a caretaker
>who would enjoy doing it?) and on those outcomes for which there is ample
>evidence (e.g., a modest, possibly temporary increase in the number of
>symbols when both gestures and words are counted). There is no need to
>reach beyond this to apparent effects that are large or of long duration
>and for which there is no obvious mechanism, such as the claim of a
>12-point IQ boost at 8 years.  (Evidence and plausibility of verbal
>facilitation lies between these extremes.)
>
>Isabelle Barriere made the interesting point that, even as parents of
>hearing toddlers buy videos and take baby sign classes, the old worries
>about interference live on recommendations to parents of children with
>cochlear implants. I would add that the issues and relevant studies extend
>far beyond the baby sign literature, especially with respect to
>syntactically structured language.
>
> > Dear Info-CHILDES,
> >
> >       During the flurry of discussion of the C/P contrast, there was
> > an message from Mechthild Kiegelmann that seemed to slip under the radar
>screen.  This message summarized replies to a query about Baby Signs.  I
>spent some time tracing the various web links involved and I would like to
>draw colleagues' attention to one issue in this
> > research that troubles me.  This is the status of a report by
> > Acredolo and Goodwyn, which is cited prominently at www.babysigns.com
>and www.signingtime.com (STResearch_Summary.pdf).  This reports
> > speaks of a 12 point "increase" in IQ measured at age 8 for children who
>are taught Baby Signs when they are toddlers.  Interestingly,
>Mechthild's links also point to an article from the Canadian Language and
>Literacy Research Network by J Cyne Johnston, AndrÃ©e Durieux- Smith, and
>Kathleen Bloom that challenges the claims of this study by noting that it
>provides no description of subject recruitment
> > provedures, attempts at random assignment, or evidence of any
> > pretesting.  They conclude that, "The high accessibility of a wide range
>of baby signing products is not matched by good quality
> > evidence that would reinforce manufacturers' claims."
> >        It is worth adding that the groups were already different when
> > the Bailey was given at 24 months, but this is presented not as
> > evidence of initial group differences, but rather as the result of the
>initial effects of the treatment.  The relevant study was
> > presented as a conference paper at ISIS in 2000, but has never been
>published in a journal.
> >     I have mixed feelings about the plausibility of this result.  I
> > certainly do not view IQ as immutable and genetically-given.  I am also
>quite convinced that Baby Signs provide an excellent method for
>achieving early and rewarding communications with toddlers.  However, I
>find it difficult to believe that a program in Baby Signs alone could
>achieve a 12-point increase in IQ when several years of Head Start lead to
>nothing measurably permanent.
> >     I hope that academic researchers take these unpublished claims
> > with a healthy grain of salt.  If there are newer studies supporting
>these claimed gains in IQ, I would love to learn about them.
> >
> > --Brian MacWhinney, CMU
> >

Chris J. Boyatzis, Ph.D.
Associate Professor of Psychology
Department of Psychology
Bucknell University
Lewisburg PA  17837

Office phone:  570.577.1696
FAX  570.577.7007
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