Infants can use not only an actor’s previous actions and emotional expressions but also her words to reason about her goals and actions – By 12 months, infants expect a change in word to signal a change in goal object – By 10 months, infants possess some sensitivity to verbal information, but they need more exposure & have difficulty forming new expectations.

1. The development of
infants' ability to use verbal
information
when understanding others’ goals
Hyun-joo Song
Yonsei University, Korea
Seminar on Child Language Development,
Kyoto Institute of Technology
July 11, 2015

2. Do infants also attribute goals
to others?
• Infants can detect goals that involve acting on
an object
(e.g., Csibra et al., 1999; Gergely et al., 1995; Kiraly et al., in press;
Luo & Baillargeon, in press; Onishi et al., 2005; Phillips et al., 2002;
Song et al., 2005; Thoermer & Sodian, 2001; Woodward, 1998, 1999;
Woodward & Somerville, 2000)

3. Woodward (1998)
Habituation Event
New-goal Test EventOld-goal Test Event
Infants attribute goals to others
<

4. • Previous actions (e.g., Woodward, 1998)
• Eye gaze and emotional expressions
(e.g., Carpenter, Akhtar, & Tomasello, 1998; Phillips,Wellman,
& Spelke, 2002)
• Verbal information (Martin, Onishi, &
Vouloumanos, 2012)
What information do infants use
to determine others’ goals?

5. Martin, Onishi, & Vouloumanos (2012)
Familiarization event
Pre-test display event
<Test event>
Old-object test event
New-object test event
“Koba! Koba!”
“Koba! Koba!”
<

6. the infants assumed
(1)agent1’s communication specifically referred to the
target object (since agent2 was absent during the
familiarization trials, the word ‘‘koba’’ had to convey
sufficient information to identify the target object)
(2) expected agent2 to know the referent of the word
‘‘koba’’
(3) detected a violation when agent2 picked up the non-
target as opposed to the target object
Martin, Onishi, & Vouloumanos (2012)

7. The present research
• Question:
– Can infants interpret a change in
communication as signaling a possible
change in the agent’s upcoming actions?

8. “A dax!”

9. “A pilk!”

10. Song, Baillargeon, & Fisher (2014, Expt 3)
• 7.5-month-olds
• Word or no-word condition
• New-goal or old-goal event
Song, Baillargeon, & Fisher (2014). The Development of Infants’ Use of Novel Verbal
Information when Reasoning about Others’Actions. PLoS ONE 9(3): e92387.
doi:10.1371/journal.pone.0092387

11. Results: 7.5-month-olds
0
5
10
15
20
25
30
35
40
MeanLookingTime(sec)
New-goal
Event
Old-goal
Event
No-word Condition Word Condition
* *

12. So,
• 7.5-month-olds ignored the actor’s words
when reasoning about her goal object.

13. Song, Baillargeon, & Fisher (2014, Expt 1)
• 12-month-olds
• Word or no-word condition
• New-goal or old-goal event

14. Results: 12-month-olds
0
5
10
15
20
25
30
35
40
MeanLookingTime(sec)
New-goal
Event
Old-goal
Event
No-word Condition Word Condition
*

15. Two possible interpretations
of 12-month-olds’ data
1. Infants were confused by the verbal information

16. 2. Infants attempted to use the verbal information
when reasoning about the actor’s actions.
Perhaps Infants realized that the actor’s change in word
signaled a possible change in her actions
1) Upon hearing the new word, they cancelled their
expectation that she would reach for the same object
(egg)
2) The infants did not have the ability or the time to
develop a specific expectation as to what the actor
might do next

17. Which of these two possibilities
is correct?
Song et al. (2014, Expt 2)
• 12-month-olds
• Word, mixed-word, or delayed-word condition
• New-goal event during test

18. Word Condition
“A pilk! A pilk!”
“A dax! A dax!”

19. Mixed-word condition
- Words varied across familiarization trials

20. Mixed-Word Condition
“A pilk! A pilk!”
“A dax! A dax!”
or “A corp! A corp!”

21. Predictions
• If the infants in the word condition were
confused by the words, then those in the
mixed-word condition should also be
confused.
– Therefore, the infants in the word and mixed-word
conditions should look equally at the new-goal test
event.

22. Predictions
If the infants in the word condition used the
actor’s words to reason about her actions, then
the infants in the mixed-word condition might
ignore the words, which were not clearly related
to her actions.
– Therefore, the infants in the mixed-word condition
might look reliably longer at the new-goal test
event than those in the word condition.

23. Results: 12-month-olds
Mean Looking Times at New-goal Test Event
0
10
20
30
Word (Experiment
1)
Mixed-word .
MeanLookingTime(sec)
*
Word
Condition
Mixed-Word
Condition
New-goal Test Event
*

24. Delayed-word condition
– The actor said the words after, rather than before,
reaching for and grasping one of the toys.

25. Delayed-Word Condition
“A dax! A dax!”
“A pilk! A pilk!”

26. Predictions
• If the infants in the word condition were
confused by the words, then those in the
delayed-word condition should also be
confused.
– Therefore, the infants in the word and delayed-
word conditions should look equally at the new-
goal test event.

27. Predictions
• If the infants in the word condition used the
actor’s words to predict her actions, then the
infants in the delayed-word condition should be
unable to do so, because the words arrived too
late to be of use.
– Therefore, the infants in the delayed-word
condition might look reliably longer at the new-
goal test event than those in the word condition.

28. Results: 12-month-olds
Mean Looking Times at New-goal Test Event
0
10
20
30
Word (Experiment
1)
Mixed-word Delayed-word
MeanLookingTime(sec)
*
Word
Condition
Mixed-Word
Condition
Delayed-Word
Condition
New-goal Test Event
*

29. So,
• The infants chose not to use the actor’s
words to reason about her actions,
– When words varied (Mixed-word condition).
– When words arrived after the action
(Delayed-word condition).

30. Two possible interpretations
of 12-month-olds’ data
1. Infants in the word condition were confused by
the verbal information
2. Infants attempted to use the verbal information
when reasoning about the actor’s action
• Upon hearing the new word, they cancelled their
expectation that she would reach for the same object

31. Kim & Song (2015)
• 10-month-olds
• Two-word condition
Word in a sentence context
“Papu-ga it-ne”
There is a papu

32. 10-month-olds
0
5
10
15
20
25
meanlookingtime(sec)
new-goal old-goalnew-goal old-goal
* 6 familiarization trials

33. Conclusion
• Infants can use not only an actor’s previous actions
and emotional expressions but also her words to
reason about her goals and actions
– By 12 months, infants expect a change in word to
signal a change in goal object
– By 10 months, infants possess some sensitivity to
verbal information, but they need more exposure &
have difficulty forming new expectations.

34. Special thanks to…
• National Research Foundation of Korea
(NRF-2012-S1A3-A2033375)
• Undergraduate and graduate research assistants of Child
Development Lab at Yonsei University
• Babies and parents in
Seoul, Korea
• Renée Baillargeon
University of Illinois
• Cynthia Fisher
University of Illinois
• Kristine H. Onishi
McGill University