It was published in the Proceedings of the National Academy of Sciences.
Knowing how critical early-language acquisition is to a person’s future success, Trueswell and Gleitman have long investigated the mechanisms involved in how children learn their first words. One of their previous studies suggests that children learn these words in what might be described as a “eureka” moment — that is, only after “highly informative” examples of speech that clearly connect the word to the thing it refers to.
The researchers suspected these highly informative examples would matter much more than the sheer amount of talk in the home when it came to which children learned more words. To determine if this was the case, they set out to track the long-term effects of these examples, seeing if children who had been exposed to them more often did better on a vocabulary test three years later. However, to begin this study, the researchers first had to determine what constituted highly informative speech.
To quantify this phenomenon, the researchers visited more than 50 families from various backgrounds in their homes and videotaped parents interacting with their children. They made these visits when the children were 14 months old and then again four months later.
The researchers edited these taped interactions down to 40-second segments, each centered on one instance of a parent saying a common, concrete noun, such as “book,” “ball” or “dog.” The researchers showed these segments to adult volunteers but muted the video until the parent reached the target word, which was replaced by a beep. The volunteers were asked to guess the word the parent was saying in each instance.
“We purposely chose videos of parents interacting with their children in the home because of the complexity there,” Trueswell said. “Our intuitions are a little misleading; we think it’s going to be a simple environment, but there’s all sorts of things happening at once and changing on a second-by-second basis. Identifying a particular word’s referent, especially when you don’t know any words to begin with, is not a simple task.”
By taking out the verbal context, the volunteers experience the taped situations in the way the children experience it, as they don’t yet understand any of the words and must rely on environmental clues to first learn them. The researchers also discarded any examples where the child might already know the word in question. In those cases, volunteers might be able to pick up clues from the child rather than the parent, and the parent might be less conscientious about connecting the meaning of a word to its referent.
“We see that the more an environment maximizes the ‘here and nowness’ of speech, such as when a parent is gesturing or looking at the object in question, the more likely it is that an interaction will be highly informative,” Gleitman said. “And it turns out this is surprisingly hard to do; only 7 percent of the examples were able to be guessed correctly by more than half of the adults we showed them to.”
If more than half the adults could guess an example’s target word correctly, that suggested the interaction was highly informative. The researchers used this approach to determine approximately how frequently each child in the study heard these highly informative examples. They found a surprising amount of variability: the parents who provided the highest rate of highly informative examples did so 38 percent of the time, while those who provided the lowest rate did so only 4 percent of the time.
“This means that some parents are providing 10 times as much highly informative learning instances as others,” Gleitman said.
The effect of this discrepancy was clear when the researchers tracked how well each of the children did on a standard vocabulary test three years later. The more frequently a child heard highly informative examples of speech, the better he or she did on these tests.
Increasing the quantity of speech was also beneficial but only because it increased the number of chances parents had to provide highly informative examples.
“Fortunately, low-informative instances seem to be ignored,” Trueswell said. “By talking to children more, it’s not as if you’re giving them bad data, you’re only increasing the opportunity to find those nuggets.”
Critically, the rate at which a parent gave highly informative examples to their children wasn’t correlated to the amount they spoke to them in total. This is potentially hopeful news, given the studies that link low socioeconomic status, or SES, to low speech quantity and thus to poor scholastic performance.
“There are a variety of reasons why low-SES parents are speaking less to their children,” Trueswell said, “but, when they do speak to them, their natural predispositions about talking about the ‘here and now’ don’t seem to be correlated to their SES.”
And while the exact mechanisms that lead to a particular bit of speech being highly informative will need to be determined in future research, the Penn team’s study shows how these quality examples can have an overriding and lasting effect on an important stage of a child’s development.
“You can see this effect even with all the variations in their lives and personalities,” Gleitman said. “Through all of that noise, the signal of a linear relationship between these highly informative examples and their children’s performance on that vocabulary test three years later shines through.”
The research was supported through the National Institute of Child Health and Human Development.
Evan Lerner | EurekAlert!
Rutgers-led innovation could spur faster, cheaper, nano-based manufacturing
14.02.2018 | Rutgers University
New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
21.02.2018 | Life Sciences
21.02.2018 | Life Sciences
21.02.2018 | Materials Sciences