Learning new words by a toddler is not a simple matter. They hear unfamiliar words uttered in a cluttered, complex, dynamically changing scene. How are they to know, from the vast number of options, just what it is that an unfamiliar word is supposed to point toward?
Yet, despite the myriad number of potentially “pointed-to” alternatives, learning new words is something that many toddlers do surprisingly well. Not too long after they utter their first few words, most toddlers begin to acquire new words at an astounding rate, hungrily absorbing them like a tiny purpose-built learning-machine.
How does the toddler accomplish this remarkable word-learning feat? It’s a long-standing puzzle that many cognitive and developmental scientists have taken up. The immense number of possibilities seem so potentially overwhelming that it may even seem that some sort of specialized language-based wizardry must kick in to propel the toddler’s remarkable spurt of word learning.
Bringing in some technological magic – to capture another point of view
Would it be easier to understand this mysterious language spurt if we could somehow get closer to the child’s point of view? What if we were able to see the world as it appears from the toddler’s own unique perspective – as seen from their specific child-size bodies, their particular opportunities for action (with their smaller fingers, hands, and arms), and their more limited chances for moving about. What might we learn?
An innovative way to get closer to the child’s perspective on the world is to ask the child to wear a mini “head camera.” Embedded low on the toddler’s forehead, in a custom-made soft headband, is a mini head camera. The head camera now can track what – from the child’s particular vantage point – is “out there” for the toddler to see, touch, or reach.
One team of developmental researchers in a pioneering study using such a head camera uncovered a finding that sharply spurred the team’s curiosity. The team found that the child’s play world – when discovered through the head-band camera – was highly dynamic and changing. Many objects remained in view only for seconds or split seconds, before disappearing. But interspersed among all the rapidly moving images that formed the usual turbulent “visual diet” of the active toddler, there were occasional brief moments of a different sort.
Every once in a while, despite the constant variation and dynamic changes and tremendous clutter of objects closely surrounding the child, there were occasional moments during which “there was just one object stably dominating the head camera image, being much larger in visual size because it was closer and un-occluded” (p. 179).
Make us some novel objects to play with!
The researchers wondered: “Are these periods of stable, clean, nearly one-object views optimal sensory moments for the early learning of object names?” (p. 179) Could there be something especially important about these rare moments when an object looms large and alone and dominates a toddler’s point of view?
To try to answer this question about stable one-object views, the researchers themselves first enlisted the creative help of an artist adept in making novel objects from hardened clay. To ensure that the children had not already encountered any of the objects, they wanted to conduct the experiment with purposively-constructed novel objects, so every child would be equally unfamiliar with the objects.
The artist created six novel objects, each with a unique shape and texture. These novel objects were then painted, either blue, red, or green, two objects for each color, forming two sets of three differently-colored objects. And then each object was randomly paired with one novel name: zeebee, tema, dodi, habble, wawa, and mapoo.
Next, parents and their toddlers (at a mean age of 20 months) were invited to a play session in the research lab. They were asked to sit across from one another at a small white table, in a white room, with a white floor. The parent was told the names of the six novel objects, and the objects were placed in small boxes. On the side of each box, was a picture of the object, and a reminder of the object’s name.
Parents were instructed to encourage their toddler to interact with the clay objects in as natural a way as possible. Parent and toddler then engaged in play with the objects over four toy play periods; each play period lasted just under two minutes, and each set of three toys was used twice.
The instructions did not tell the parents to try to teach their child the names of the objects, and parents were not told that their toddlers’ ability to remember the names of the objects would later be tested. All of the play period was video and audio recorded.
After the play periods, the toddlers were given a surprise memory test for the names of the novel objects. The experimenter entered the room, holding high a tray with three of the objects, each of a different color, one on the right, one to the left, and one in the middle. Looking steadfastly into the infant’s eyes (as confirmed by a later review of the video), and never at the objects on the tray so as not to unintentionally guide the child to the answer, the experimenter said, “Show me the ___! Get the __!” The experimenter then moved the tray forward for the infant to select the object. This test was completed twice for each of the six object names, each time with different distractors. The toddlers correctly reached for the novel objects more than would be expected by chance, with a few of the toddlers even learning all six novel names.
Looming visually large and alone
Now the researchers looked back at the videos of the play periods between the toddlers and their parents. And they found a clear answer to their question. In precisely those moments when parents named a novel object for their child, the child’s head-camera video revealed that the object loomed large and centered in the child’s visual field.And the more this was true, the more likely it was that the toddler later showed that they remembered the name of the object. So: the more that the object filled the center of the child’s viewpoint at the moment of the parent’s naming (e.g., “zeebee”), the more likely the child was to correctly choose the “zeebee” from the tray.
These results show that, at least in this miniature table-top “play world,” parents most often chose to name unfamiliar objects at precisely those moments when their child was already visually attending– and often also touching– an object. And the more strongly the child’s visual attention was centrally and predominantly focused on that object, the more likely the child was to later recognize that name.
Once we get closer to the child’s perspective, at least a little of the mystery of how children so adeptly learn to correctly map words to the intended parts of the world is dispelled. It turns out that, at these moments of naming, rather than there being a teeming multitude of competing items to which the unfamiliar label might apply, there is often only a single object in central view.
Perspective-taking and another developmental mystery
Concretely and specifically trying to see the world through a young child’s eyes may help to explain another developmental mystery – that is also closely connected to exploration. Why do toddlers learn to walk? Why do children move from a form of locomotion that they have fully mastered and even become experts at – that of crawling – and embark on the decidedly difficult (and not infrequently painful) task of learning to walk?
A partial explanation may be that what they can seewhen they walk (rather than crawl) is very different. Data from a head-mounted eye-tracker worn by fifteen 13-month old children who were still crawling as their primary form of locomotion compared with fifteen 13-month old children who had begun to walk, revealed many differences. For crawlers, the “scene camera” revealed that on about 25% of their “steps” the only thing in view was the floor. Lifting their heads while crawling was an awkward, gravity-defying move. Compared to crawlers, walkers could see many more enticing toys, and could see their caregiver’s face twice as often.
It may, in part, be the tantalizing promise of getting to see and to experience more – a world that is richer, more varied, more social, and more extended – that motivates the young infant to stand up and begin to walk.
By literally and concretely trying to see “what’s in view” for a child, we can begin to understand how children creatively explore and learn about the world. The transition from crawling to walking is a developmental “cusp” that completely changes the options and opportunities open to the child.
What “cusps,” akin to those that confront the toddler who is first learning to walk, might we, as adults, be over-cautiously stepping back from – and so needlessly limiting much of our view? How can we be encouraged to reorient our own perspective to explore the farther reaches of what we can’t even now see?
Kretch, K.S., Franchak, J.M., & Adolph, K.E. (2014). Crawling and walking infants see the world differently. Child Development, 85, 1503–1518.
Pereira, A. F., Smith, L. B., & Yu, C. (2014). A bottom-up view of toddler word learning. Psychonomic Bulletin and Review, 21, 178–185.
Smith, L. B., Yu, C., & Pereira, A. F. (2011). Not your mother’s view: The dynamics of toddler visual experience. Developmental Science, 14, 9–17.