Learning their First Words: how much detail do babies pay attention to?
The first steps are always the hardest: for beginners, word-learning is a very challenging task. To know that “ball” refers to the round bouncy thing that is great fun to drop and then make someone else pick up, you have to remember (i) the sound of the word (b-a-l), (ii) what the object looks like (round, bouncy, great fun…), and (iii) the crucial fact that the sound form of the word and the visual form of the object go together (this is what is referred to as associative word learning).
Because associative word learning is so complex, at first babies may not pay attention to all the details in the sound of the word. We are interested in studying exactly how much detail babies use or don't use when learning their early words, and how this use of detail develops over time. Also, we are trying to see if there are ways that we can make associative word-learning easier for babies.
Learning new words, but can we prove it?
We know that infants as young as 6 months old can understand some words in everyday situations, but this has been difficult to demonstrate in research settings. In this study we will present infants with words that they may know already; they will hear the word played while watching the corresponding image on a screen. We will then present new, nonsense words with corresponding novel images to see whether they can associate the word they are hearing with the image they are seeing. If infants recognize the novel word, then we expect them to look at the correct image on the screen when presented with more than one image at once. We are testing whether infants will learn these words earlier when they are presented in sentences instead of in isolation (e.g. "Look at the bottle!" versus "Bottle!"), as the former case is more similar to the speech they hear every day. Preliminary results of this study were presented at Development Conference in May 2014. Thank you to everyone who has participated so far!
The effect of mixed-up labels on word-learning
Previous work has demonstrated that a brief training period with familiar word-object pairings (e.g. seeing a shoe and hearing “shoe”) will help infants to subsequently learn a completely new word-object pairing. In our study, we will present three familiar objects but will mix up their names (e.g., they will see a shoe, but hear “kitty”). We would like to see whether this “mixed up” training phase will help or hinder infants’ abilities to learn new words in detail. If it hinders these abilities, this would be good evidence that babies tap into their knowledge that nouns go with objects, and not that any pre-exposure to words and objects will enhance word learning. Thank you to all who have participated in this study so far!
Using words to form categories
Research has shown that hearing a word in either a familiar or an unfamiliar language while seeing an object on-screen can help 3-6-month-olds categorize objects, but hearing a non-linguistic sound does not have this effect. As of yet, only monolingual infants have been tested, so we would like to see how bilingual infants perform in comparison. In this study, we show infants many examples of an object on a screen (for example, many differenttypes of cars, one at a time). Once they get bored of this, we show them a member of the category (such as a car) and another type of object (such as a boat) to see whether babies understand that a new car, as opposed to another type of vehicle, belongs to the category “car.” Testing for this study began in March 2014!
Understanding Bilingual and Monolingual Language Acquisition via Brain Waves
Previous research has shown that bilingual babies may have a harder time distinguishing similar phonemes and similar sounding words at an age where monolinguals can. One hypothesis to explain this is that there may be a slight delay in bilinguals because they are experiencing a variety of input (including different accents and pronunciations of words). Another hypothesis is that bilinguals actually have no problem at all discriminating sounds and words, but that there was a problem with how researchers tested them. Previous methods have relied on infants being surprised by a sound or word change and looking longer; however, slight changes in words may not be surprising for bilinguals given their variable sound and word environment (e.g., Dad says “Le bébé” and Mom says “Baby”). In this study, we will be testing 7- to 9- month old monolingual and bilingual infants. Monolingual babies serve as the basis of comparison to bilingual babies. We will be looking at their ability to discriminate vowel contrasts, such as the difference between bait and boot. To do so, we will use the event-related potential technique (ERP), which has been widely used to examine brain activity and it is a well-established technique to study infant language development. It is non-invasive and completely safe. We will first place a cap on your baby’s head. This cap has small discs that measure the electrical activity in your baby’s brain. It does this by picking up the electrical fields emitting from your baby’s scalp. This is completely non-invasive. We will squeeze some gel, like the gel used for ultrasounds, onto the discs so that they make contact with the scalp. Your baby will sit in your lap during this whole process. We will then go in to the testing room. The cap will be plugged in to a computer that will record your baby’s brain activity, millisecond by millisecond. She/he will be sitting in a high chair and you will be sitting right behind him/her. An experimenter will be in the room with you helping entertain your baby while she/he watched a silent video. While the video is playing, she/he will hear a sequence a vowels. Most of the vowels will be the same (e.g., /e/), but your baby will randomly hear a different vowel from time to time (e.g., /u.). If your baby can detect the difference between the vowels, their brain emits a unique electrical pattern. We will examine your baby’s brain waves after the experiment to see if that pattern is present. After the study, we will return to the main room and slip off the cap. There may be some gel remaining on your baby’s head. We will provide you with baby wipes and baby shampoo to clean the gel. We will be happy to help you do this, if you wish.
How do infants learn two languages and is it related to their cognitive skills?
One of the first steps of learning words in infancy is to parse out individual words from fluent speech. This proves to be a difficult task, as speech contains no consistent cues to indicate individual words (e.g. no reliable pauses between words). Previous studies suggest that infants can overcome this challenge by tracking natural regularities in their language. For example, infants are shown to be able to track how sounds and syllables co-occur in fluent speech. Based on the co-occurrences, infants find the underlying structure of their language and use this structure to identify individual words. However, all previous work focused on how infants find individual words in one single language. With the emphasis of bilingualism in the capital, it is essential for us to investigate how babies learn two languages simultaneously from fluent continuous speech. In this study, we aim to fill in this knowledge gap by investigating how monolingual and bilingual babies track two new languages in a research setting. Infants will be presented with two artificial languages that are mixed together and they will be tested on their ability to identify words from each language. In addition, we will examine whether babies’ capacity to successfully identify words in each language is related to certain cognitive skills. Thus, in the second half of the study, we will test infants’ cognitive skills by measuring the time required to switch their attention to two different visual locations. We expect that infants’ cognitive skills will be related to their ability to learn two new languages simultaneously because both tasks require infants to be able to switch attention between two inputs. This study involves two lab visits within two week(s). Each lab visit will last around 30 to 40 min and all appointments will be booked at parents’ convenience.