RSS Feed

Tag Archives: 2 years

Listen Up! (24 months)

**How young children learn new words through overhearing**

Have you ever wondered how kids pick up so many words that you never used when talking to them? Words that you may want them to learn or not J. Not all cultures speak directly to their children as much as American mothers, so there must be other mechanisms through which children learn language. Researchers have examined this in toddlers to see how kids learn new words by overhearing them while playing with a toy.


  • A confederate, i.e., a friend you can talk to so that the child has a conversation to overhear
  • Four unfamiliar objects, that is, objects that you know your child does not know how to label.  In the study they used: a wallpaper roller, a noisemaker, an oddly shaped yo-yo, a small wooden toy made of two connected disks, etc.
  • A bucket that the four objects fit in
  • One nonsense word: dax
  • A toy to distract the child. In the study, they used a pop-up toy like this one so that it required the child’s attention to manipulate it.

pop-up dinosaur


For the scenario, set the child with the toy about 1 meter away from where you and the confederate will play a game.  Tell the child that he is waiting his turn.  Do not make eye contact with the child as you go through the objects one by one with the confederate.

Choose one of the objects to be the target object. You will pull that one out of the bucket second and will introduce it with the nonsense word.  While the child is playing with the toy nearby, go through the following dialogue (in an excited voice) with the confederate three times:

– Say “I’m going to show you what’s in here. Want to see what’s in here? I’ll show you what’s in here.”  Pull the first object out of the bucket. Let the confederate hold it and then put it back in the bucket.

– Say “I’m going to show you the dax. Want to see the dax? I’m going to show you the dax.” Pull the target object out of the bucket. Let the confederate hold it and then put it back in the bucket.

– Say “I’m going to show you what’s in here. Want to see what’s in here? I’ll show you what’s in here.”  Pull the third object out of the bucket. Let the confederate hold it and then put it back in the bucket.

– Say “I’m going to show you what’s in here. Want to see what’s in here? I’ll show you what’s in here.”  Pull the fourth object out of the bucket. Let the confederate hold it and then put it back in the bucket.

After going through this object-finding routine three times, you do one round of this with the child, but do not give the nonsense word when you take the target object out of the bucket; just introduce it in the same way as the other objects.

Then, during the comprehension phase, place all four of the objects in random positions on a tray and ask the child to show you the dax.

Notes & Observations

What did you observe?  Was your child engaged with the toy? Did your child learn the new word through overhearing despite being distracted?

Research Findings & Extension

The researchers found that 24-month-old children could reliably choose the target object when asked to show them the “dax”.  They also ran a condition of the study where children were not given a toy to distract them and they learned the new word through overhearing equally in both scenarios.  The researchers analyzed videotapes of the research sessions to track the children’s attention during the task, and interestingly, the children tended to shift their attention to the adults’ conversation when they heard an unfamiliar word used before the target object was shown. This suggests that children are actively trying to gather information, such as mapping new words to objects.  The findings inform us about how children learn outside of direct conversation.


Akhtar, N. (2005). The robustness of learning through overhearing. Developmental Science, 8, 199-209.


Yours, Mine, and Ours (2-3 years)

**How children develop an understanding of ownership**

Anecdotally, we have all seen that children can be possessive with their objects.  But knowledge of who owns an object is not obvious from looking at it, so how and when do children come to know that something belongs to them versus someone else? How do they keep track of an object’s history and discriminate their object from other similar objects? Researchers have started to look at this question with clever experiments with 2 and 3 year olds that disentangle which factors children pay attention to when determining ownership (Gelman, Manczak & Noles, 2012).


  • Set 1: a set of three different objects, but from the same category (e.g., three different looking car, animal, or food toys)
  • Set 2: a set of three objects that are identical (e.g., three of the same toy cars, animals, or foods)
  • Set 3: a set of three objects, two of which are from the same category (e.g., two different cars) and one object which is plain and undesirable (e.g, a piece of Styrofoam or cardboard)
  • A tray to place the three objects on during the question phase


Sit at a table with the child with the objects out of view.

Trial 1:  Start with the objects from Set 1, which you will take out one at a time. For this set, it does not matter which of the three objects are assigned to you or the child. For the labeling phase, bring out the first object and say “This is yours; this is for [child’s name],” and put it in front of the child.  Then, bring out the second object, show it to the child, and say, “This is mine; this is for [your name],” and place it in front of yourself.  Finally, bring out the third object, hold it up to show the child, and say, “See this; look at this,” and then place it on the table equidistant from the other two objects.  For the question phase, take the three objects and place them on a tray in the order that they were first presented as the child watches.  Then ask: (a) “Which one is yours?” and (b) “Which one is mine?” and note whether the child picks the correct objects for the two questions.

Trial 2:  Follow the above procedure with the objects from Set 2 and note the responses. For this set, it does not matter which of the three objects are assigned to you or the child since they are identical.

Trial 3: Follow the above procedure with the objects from Set 3 and note the responses. For this set, be sure to assign the plain object to the child.

Notes & Observations

What did you observe? Did your child keep track of which object he was assigned for each set of objects?  Were any of the sets easier or harder?

Research Findings & Extension

The results of the study were different based on the age of the child and the make-up of the set of objects.  Both 2 and 3 year olds were good at the task with varied sets of objects like Set 1, meaning that they kept track of them and correctly answered the questions about which object was assigned to themselves and the researcher.  The set of identical object was more difficult for the 2 year olds but the 3 years did well on this task, meaning that they tracked their object “through space and time” using the information they were told – even though all three objects looked exactly the same. Although the researchers didn’t try this, it would be fun to see just how good children are at tracking their object visually, Three-Card Monte style J Finally, the set where the child gets the plain object was hardest for the 2 year olds who actually did a better job of keeping track of the researcher’s more interesting object than their own. The researchers also looked at a phenomenon called the “endowment effect” where people tend to like something more just because they own it – there’s a lot more to study about ownership, but it’s clearly an understanding that takes root early on.


Gelman, S., Manczak, E., & Noles, N. (2012). The nonobvious basis of ownership: Preschool children trace the history and value of owned objects.  Child Development, 83, 1731-1747.

Fitting In (18-24 months)

**How children make errors when judging the size of objects they interact with**

Have you ever seen a two-year-old trying to get his hands or feet into something way too small for him?  Not pretending, but seriously and persistently trying, say, to fit into a toy car that would be impossible to get into?  Well, you’re not alone.  Dr. Judy DeLoache and her colleagues noticed the same phenomenon in young toddlers and decided to study what they called “scale errors.” Because these occurrences are infrequently spotted in everyday life, they created a lab situation that would make children’s errors in judging the scale of objects more likely (of course, they still don’t always occur!).  Setting this one up at home would be a commitment, but the errors are really interesting to witness.


  • Large (appropriate for a child to actually get into) and small (not miniscule, about doll house-sized) versions of the same object.  For example, the original study used a Little Tikes Cozy Coupe ® car and a small toy version of it (which also had movable parts).  A chair, slide, or wagon could also be used.  The two objects should look as identical as possible.
  • A confederate


Have the child come into the room where the large object (and little else, if possible) is located and let him play with it as he normally would for 5-10 minutes. Then take the child out of the room and have your friend replace the large toy with the smaller replica, placing it in the same location and removing the large toy from the room. Do this without the child seeing and without mentioning anything about the change.

When you bring the child back into the room, do not comment on the change even if your child reacts.  Let him explore on his own, or if he is hesitant, perhaps suggest that he play with the toy.  Watch carefully to see if your child has a momentary lapse in understanding how to interact with the object.

Notes & Observations

What did you notice? How did your child react?  Did he try to perform any of the same actions with the small object as he did with the large object?

Take a look at some clips from the DeLoache lab of children making a scale error with the small objects:

Research Findings

DeLoache et al. (2004) found that 18 to 20 month-olds are most likely to make this kind of mistake. By 24 months, children hardly ever make these kinds of errors. Psychologists believe that when children display this sort of behavior, it indicates a time in their development when their action planning is misguided. In the case of this phenomenon, the children are thinking of the larger version of the object when they are planning how they will act on the smaller version.  Even if you can’t re-create the study, many people report children doing this spontaneously, so keep an eye out!


DeLoache, J.S., Uttal, D.H., & Rosengren, K. S. (2004).  Scale errors offer evidence for a perception-action dissociation early in life. Science, 304, 1047-1029.

Pick This, Not That (30-36 months)

**How children use rules to learn the meanings of new words**

 How can children learn new words so quickly?  Do they have some way to match new objects to new words that they hear and will they resist giving an object two names?  Many psychologists have studied what they call the “mutual exclusivity” bias where children learning new words avoid giving an object they already know another name and instead assign a new name to a novel object.  Below I describe one of the first studies to show this learning mechanism: Markman & Wachtel (1988).


  •  Six familiar objects, that is, objects that you know your child knows how to label. In the study they used: a banana, a plate, a cup, a spoon, etc.
  •  Six unfamiliar objects, that is, objects that you know your child does not know how to label.  In the study they used: a cherry pitter, a lemon wedgepress, tongs, an odd shaped container, etc.
  •  Six nonsense words.  Researchers use a variety of words that are novel to children to test out their theories of word learning.  For example, you can use:  fep, bleen, dorn, febbit, blick, and plog.


Sit on the floor across from the child.  Tell the child, “I’m going to show you some things and ask you to pick some. Listen carefully and give the best answer you can.”  Place a pair of one familiar object and one unfamiliar object in front of the child.  Ask him to “Show me the X” using one of the nonsense words from your list and record which object your child picks.  Do not provide any feedback.  Continue this process with the next five pairs of familiar and unfamiliar objects, using a different nonsense word for each pair.

Notes & Observations

What did you observe? Did your child pick the novel object when you asked to see the “fep” or other novel word?  What do you think he would have done if you said “show me one”?

Research Findings & Extension

The researchers found that when asked to pick the object referred to by the nonsense word, children picked the unfamiliar object on almost 5 out of 6 trials.  This was more often than expected by chance; in contrast, they chose randomly in the condition where the researchers asked the children to “show me one.”  Thus, the children were not just gravitating toward the unfamiliar object; the presence of the novel word compelled them to pick the novel object.  The paper goes on to test many different variations, including how children attribute novel words to parts of objects.  Others have looked at bilingual children and how they suspend this bias, since they, of course, need to assign two words to each object, one in each language.


Markman, E.M. & Wachtel, G.F. (1988).  Children’s use of mutual exclusivity to constrain the meanings of words.  Cognitive Psychology, 20, 121-157.