The speech commonly addressed to infants infantdirected speech or IDS has multiple functions, includ

1
Happy, but Not Sad Dynamic Speakers Facilitate
Word Recognition in 11-to-13-Month-Old Infants
Naureen Bhullar1 Robin Panneton2 1Department of
Psychology, Widener University, Chester, PA
19063 2Department of Psychology, Virginia Tech,
Blacksburg, VA 24060
Introduction and Purpose
Procedure
RESULTS Mean Heart Period in Happy Vs Sad
Condition

• The speech commonly addressed to infants
  (infant-directed speech or IDS) has multiple
  functions, including communication of emotion and
  highlighting linguistic aspects of speech.
  However, these two functions are most often
  studied separately so that the influence of
  emotional prosody on linguistic processing in
  infants has rarely been addressed.
• Given that language learning during infancy
  occurs in the context of natural infant-caretaker
  exchanges that most certainly include emotion
  communication and co-regulation, it is important
  to integrate the concepts of emotional
  communication and linguistic communication in
  studying language learning
• Even though the bulk of research on
  communicative development has involved infants
  perception of the linguistic aspects of speech
  (e.g., phoneme discrimination, word recognition),
  the indexical and affective qualities of voice
  might be equally, if not more important to the
  infant, and are often ignored
• The current study addressed the issue of whether
  communicative affect impacts infants attention
  to language by examining the influence of both
  positive and negative emotion, as expressed in a
  bimodal context (face voice), on word
  recognition in 11-to-13-month-old infants.
  Emotion information in both the face and the
  voice was considered because of the general
  importance of multimodal information on infants
  perceptual learning, and because communication is
  a multisensory event involving redundancy of
  information across visual and auditory domains.

• 11-to-13 month-old infants (n 45) in
  infant-controlled habituation
• Infants presented with AV movies of a woman
  saying two carrier sentences with a common target
  word (e.g. neem) X in Happy Condition X in
  Sad Condition
• 50 reduction in mean looking time (across two
  consecutive trials) relative to the mean of the
  first two trials (baseline)
• During test, alternating trials of same
  sentences, same emotion, but either Familiar or
  Novel Target Words.
• Table below illustrates two examples of
  experimental sessions one Happy Condition and
  one Sad Condition.

• Mean heart period during Familiar and Novel
  trials was compared across Happy and Sad
  conditions in two different epochs (0-3 sec
  (Orienting) and 3-9 sec (Sustained Attention).
  The results showed
• Significantly slower heart rate (higher heart
  period) on novel trial (both epochs) in the Happy
  compared to the Sad condition
• No significant differences in heart period by
  epoch across either the Happy or Sad conditions.

• OF NOTE
• According to HR data, infants in the Sad
  Condition did pay attention overall (means across
  trial typefamiliarnovel).

• Happy Sentences
• This is the sweetest NEEM that I have ever
  seen!
• We all laughed at the big, red NEEM.
• Sad Sentences
• The poor, scared NEEM started to cry.
• He lost his best NEEM.

Interpretations

• Eleven-to-thirteen month-old infants showed word
  recognition in the Happy condition since they
  looked longer on novel trials compared to
  prechange and familiar trials. Moreover, their
  heart rate was also significantly slower on novel
  trials compared to familiar trials. Happy speech
  might be attracting and maintaining attention in
  infants more efficiently than Sad speech in an AV
  context.
• Infants in the Sad condition did not show a
  significant difference in looking times between
  novel and familiar trials. Also, their Heart
  Rate was similar across novel and familiar
  trials. This suggests that the sad speaker
  sustained their attention, independently of what
  she was saying.
• Across Happy and Sad Conditions, there was no
  significant difference in looking on baseline
  trials and the number of trials to reach
  habituation, again suggesting equal amounts of
  attention to each
• Several new conditions will be tested
• Switching emotions from Habituation phase to
  Testing phase to assess if the differential
  effect is on encoding, recognition, or both
• Creating incongruent AV displays (e.g. Happy
  Face/Sad Voice) to assess the relative
  contributions of vocal and facial sources of
  emotion

RESULTS Looking times in Happy Vs Sad Condition
Auditory-Visual Movies

• Recordings were made of a Caucasian mother
  saying prescripted sentences containing a target
  nonsense word (neem or boog). She produced
  half of these sentences in a happy emotional
  valence and the remaining half in a sad emotional
  valence. The actual content also supported the
  emotional valences.
• 45 undergraduate students rated each of the
  sentences on a emotional valence scale from 0 to
  10, with 0 indicating very sad and 10 very happy.
  The two happy and two sad utterances with the
  most extreme ratings were used in this study.

• Infants in the Happy, but not the Sad condition,
  looked longer during novel trials (M 14.39,
  SD6.45) compared to prechange trials (M8.89,
  SD3.77), t(17) -2.95, plt 0.01.
• Infants who completed both trial blocks (4 novel
  and 4 familiar) looked longer during the novel
  trials in the Happy, but not the Sad, condition
  (M14.02, SD5.71) compared to familiar trials
  (M9.15, SD3.65), t(12)-3.17, plt0.01

• The acoustic characteristics of these movies were
  analyzed using PRAAT software.
• The mean F0, F0 range and intensity of happy
  speech was significantly higher than sad speech.

Familiar Vs Novel
Infant Perception Lab www.psyc.vt.edu/infant_spe
ech
Presented at the XVIth 2008
International Conference on Infant Studies,
Vancouver