Social influences on sensorimotor integration of speech production and perception during early vocal learning

婴儿感知和发出母语声音的能力发生了巨大变化 在生命的第一年。我们的概念框架在编码奖励的背景下解释了这种可塑性 在联想学习中发挥作用的预测错误。我们的研究将测试一个重要的机制 问题：婴儿的类似言语发声的感知和运动学习之间的联系程度 社会声音体验的不同历史是由胡言乱语与社会声音的偶然配对来调节的 护理人员的强化。信号与强化物的偶然配对会诱导学习预测 联想学习模型。因此，当照顾者的社交声音奖励取决于牙牙学语时，婴儿 了解他们的话语预示着伴随着成熟的声音模式的社会强化，并开始 产生模仿护理人员提供的语音模式的类似语音的形式。我们假设社会 强化是声音发展最早阶段（6-12 个月）学习的有效驱动力 具有典型听力（TH）的婴儿。相比之下，患有先天性听力损失（HL）的婴儿将有 社会-声音互动的贫乏历史损害了早期的声音学习。然而听完之后 通过人工耳蜗进行补救，社交声音强化将促进学习，超越收益 仅由于听力水平的提高。目标 1 将检验 HL 婴儿声音学习能力较差的假设 因为他们无法从胡言乱语与社交声音奖励的偶然配对中获得同样程度的好处 作为TH婴儿。我们将比较 TH 婴儿和 HL 婴儿学习发出新声音形式的能力 基于实验操作：护理人员的社交声音强化将是暂时的 婴儿的牙牙学语是偶然的或随机的。我们预测，含糊不清的社交声音 尽管强化对于促进 HL 婴儿学习更多类似言语的模式的效果较差，但 在 HL 和 TH 条件下匹配偶然组和随机对照组之间的听力水平。 随后通过人工耳蜗进行听力矫正将有助于发声学习 基于胡言乱语的社会声音奖励。并行目标 2 将测试学习程度是否 在目标 1 中产生新的声音形式可以预测对这些相同声音的感知的改善。如果社会奖励 基于学习加强感知和生产之间的整合，那么应变训练应该 提高生产性（目标 1）和感知性（目标 2）学习。我们预测，偶然强化将 诱导 TH 婴儿声音的产生和感知之间的相关性，但发挥的作用有限 对 HL 婴儿的影响，在生产学习更有限的婴儿中相关性最低。整治 人工耳蜗植入后的听力将使社会声音奖励能够加强感知产生 随着听力水平提高而链接。这些研究首次调查了社会因素在 基于预测误差的联想学习背景下的感觉运动整合。

Infants show dramatic changes in their ability to perceive and produce vocal sounds of their native language over the first year of life. Our conceptual framework interprets this plasticity in the context of encoding reward prediction errors that play a role in associative learning. Our studies will test an important mechanistic question: the extent to which linked perceptual and motor learning of speech-like vocalizations in infants with different histories of social-vocal experience is regulated by contingent pairings of babbling with social-vocal reinforcement by caregivers. Contingent pairings of a signal with a reinforcer induce learning of a prediction in models of associative learning. Thus when social-vocal reward by caregivers is contingent on babbling, infants learn that their utterances predict social reinforcement accompanied by mature vocal patterns and begin to produce speech-like forms that emulate the phonological pattern provided by caregivers. We posit that social reinforcement is a potent driver of learning during the earliest stages of vocal development (6-12 months) in infants with typical hearing (TH). In contrast, infants with congenital hearing loss (HL) will have an impoverished history of social-vocal interactions that impair early vocal learning. However, after hearing remediation via a cochlear implant, social-vocal reinforcement will facilitate learning above and beyond gains due to improved hearing levels alone. Aim 1 will test the hypothesis that HL infants are poorer vocal learners because they do not benefit from contingent pairings of babbling with social-vocal reward to the same extent as TH infants. We will compare the ability of infants with TH versus HL to learn to produce new vocal forms based on experimental manipulations: social-vocal reinforcement by caregivers will be either temporally contingent or random with respect to their infants’ babbling. We predict that babbling-contingent social-vocal reinforcement will be less effective in promoting learning of more speech-like patterns in HL infants, despite matching hearing levels between contingent and random-control groups within both HL and TH conditions. Subsequent remediation of hearing via receipt of a cochlear implant will facilitate vocal production learning based on babbling-contingent social-vocal reward. A parallel Aim 2 will test whether degree of learning to produce the new vocal forms in Aim 1 can predict improved perception of those same sounds. If social-reward based learning strengthens integration between perception and production, then contingent training should improve both productive (Aim 1) and perceptual (Aim 2) learning. We predict that contingent reinforcement will induce correlations between production and perception of vocal sounds in TH infants but will exert limited effects in HL infants, with lowest correlations in infants with more limited production learning. Remediation of hearing following cochlear implantation will enable social-vocal reward to strengthen perception-production links as hearing levels improve. These studies are the first to investigate the role of social factors during sensorimotor integration in the context of prediction-error based associative learning.