The Science of Baby-Sign Language

    Increasingly, parents are using sign language to communicate with their infants, allowing them active communication with their pre-speaking babies (researchers refer to them as pre-lexical).  Numerous benefits have been tied to using sign language, including help in building language skills, increased IQ, and increased literacy skills. While these are obviously desirable results, my husband and I were drawn to the idea of signing with Q-ball as a way to increase our bond with her as we are better able to meet her needs through increased communication.  Not to mention the idea that we could have an earlier peak into her thoughts and personality. Super neat!

     At 8 months, Q-ball is now at the tail end of what is considered the optimal age for introducing sign language, according to Baby Sign Language Basics: Early Communication for Hearing Babies and Toddlers by Monta Briant, which we have been using as our guide.  We started using 7 signs (milk, diaper change, cat, book, rattle, mirror, and we later added eat) with her at about 5 months and have tried to practice them on a daily basis (although I must admit to took me awhile to make it a habit, and sometimes signing is the last thing that crosses my mind when trying to change a fussy, squirmy baby's diaper!) So far, we have not noticed her making any signs, but I can tell she is focusing on the signs when we make them, and she appears to get excited at the sign for "milk".

      Briant's book provides some great information as do other baby-signing resources.  But, they tend to focus on the benefits and how-tos, and do not necessarily describe how signing leads to these amazing results, so I did some research.  The study I found focused on "maternal multimodal communication"- basically using multiple methods to communicate with your infant.  Throughout the study, as with sign language, the two methods used are voice and movement or touch. 

     I found the results fascinating and another amazing example of the strong biological attachment between mother and infant (for those of are regular follows of my blog, this shouldn't come as a surprise...)  The researchers, as well as many other findings from previous studies, found that "motherese," defined as the way that mothers (and people in general) often talk to infants which includes increased changes in tone and a slower rate of speech, has evolved to meet the changing needs of infants as they develop.  In other words, mothers unconsciously provide the necessary level of support to allow their babies to learn language. 

      This is where sign language comes in.  The major way to assist infants is to communicate with them using "temporal synchrony" or visual motions and voice simultaneously. Researchers suspect that temporal synchrony serves as a way of grabbing the infant's attention. Additionally, it helps infants find word-object relations. According to the ecological perspective of development, infants use their increased senses to take in the language cues the mother provides. Likewise, according to the dynamic systems theory, the development of language is a symbiotic relationship in which the mother senses the infant's perceptual abilities and matches her style of communication accordingly.  

       The results of the study support both of these theories.  The researchers found that mothers decreased the amount of motion cues as infants aged and gained increased language abilities.  Additionally throughout all age groups studied, mothers used more hand motions with verbs than with nouns (so, within the context of the study, they were more likely to demonstrate a jump than to point to the hand puppet jumped).  This supports the fact that infants vocabularies contain more nouns than verbs.  

      So, how can you be a secure base for your baby as he learns language?  Use sign language!  Or, at the very least use lots of demonstrating actions and pointing to help your little along his path of cognitive development. 

Have you signed with your baby? What did you like most about the experience? Do you have any tips to share?

Sources:

Briant, M. (2004). Baby sign language basics: early communication for hearing babies and toddlers. Hay House: NYC.

Gogate, L., Bahrick,L., & Watson, J. (2000). A study of multimodal motherese: The role of temporal synchrony between verbal labels and gestures. Child Development, 71,(4), 878-894.

Beyond Physical Milestones, Part V: Dynamic Systems

            In the 1990s, a new developmental theory emerged. The dynamics systems approach to development seems to take Bernstein’s concept of redundancy (for a review of Bernstein and his findings, check out the first post of this series) and multiplies it by infinity. The new theory states that development is non-linear because the basic components involved (the person, environment, and the task) are in constant flux.  Consequently, each of these components must be considered from every angle in order to understand an individual’s developmental progress. This makes development truly unique to each individual and not necessarily something that unfolds along a set timeline as argued by proponents of maturation theory.  No wonder some people have started to call the dynamics system theory “chaos theory.”

            One key point of the dynamic systems theory is that human development occurs through various timescales, but these timescales cannot be treated as individual events.  Research in this field analyzes the relationships between the timescales of each component of development.  A component of human development might be a signal sent by the central nervous system and its timescale would be only milliseconds. Simultaneously, the action itself (such as crawling) might be another component which would then be analyzed by millisecond. These flashes in time might be analyzed next to the larger component of learning a new skill, a component whose timescale can be years. 

A second key point of dynamic systems theory is that these various components and timescales self-organize. Dynamic systems theorists believe this self-organization is the cooperation between the infinite components and their timescales which manifests itself through a new development milestone.  So, when all of the timescales align perfectly, baby can complete a new skill!

           
         Now, assuming that you have made it this far in the reading, an example that might clear things up. Or, only provide further support for the name “chaos theory.”  Esther Thelen, an American psychologist who was instrumental in the research that supports dynamic systems theory, proposes that there are eight sub-components in the development of walking.  She hypothesizes that when the sub-components listed below self-organize, walking emerges.  The accompanying figures show the change of the components at their different timescales (13-5) and how these components must align or self-organize with the correct environmental context in order to produce a new development milestone (13-6). 

1.    Pattern generation- The coordination of multiple muscles and joints to form a single motion.

2.    Articular differentiation- Fancy way to say that joints movement becomes unsynchronized.  In newborns, the hip, knee, and ankle joints are synchronized during kicking.  As the baby ages, however, the knee joint will move separate from the hip and ankle, which is necessary for walking.

3.    Postural control- increased ability to stand up right

4.    Visual flow sensitivity- Involves balance, awareness of one’s movements in relation to the surroundings, and vision

5.    Tonus control- The shift of dominance from flexor muscles (those that allow us to bend) to the extension muscles (those that allow us to straighten).  This reciprocal interweaving (for review of this concept see the post on maturation) is typically not complete until an infant is 7-12 months old.

6.    Extensor strength- the muscle strength to support upright movement

7.    Body constraints- Babies are just too chunky to lift their own weight, especially their legs!

8.    Motivation- the desire to move towards a goal

And remember, even if all of these components perfectly self-organize to support walking, the context or the environment still needs to be favorable to this new action.  So, hopefully baby isn’t ready to take his first step on top of an icy hill!

Sources:

Herzia, C. (1991). Motor development: Contemporary and traditional theories.  In Foundation for Physical Therapy (Series Ed.), Contemporary Management of Motor Control Problems (pp.99-126). Retrieved from http://www.udel.edu/PT/galloway/motordevelopment.pdf

Savelsbergh, G., Davids, K., van der Kamp, J., & Bennett, S. (2003). Development of movement co-ordination in children: applications in the field of ergonomics, health sciences, and sport.  London: Routledge.

Smith, L.B. & Thelen, E. (2003). Development as a dynamic system. TRENDS in Cognitive Science, 7(8), 343-348.