The roles of linguistic, cognitive, and social-pragmatic processes in word learning are well established. If statistical mechanisms also contribute to word learning, they must interact with these processes; however, there exists little evidence for such mechanistic synergy. Adults use co-occurrence statistics to encode speech–object pairings with detailed sensitivity in stochastic learning environments (Vouloumanos, 2008). Here, we replicate this statistical work with nonspeech sounds and compare the results with the previous speech studies to examine whether exclusion constraints contribute equally to the (...) statistical learning of speech–object and nonspeech–object associations. In environments in which performance could benefit from exclusion, we find a learning advantage for speech over nonspeech, revealing an interaction between statistical and exclusion processes in associative word learning. (shrink)

Recent work asked if visual cues facilitate word segmentation in adults and infants. While adults showed better word segmentation when presented with a regular visual cue, infants did not. This difference was attributed to infants' lack of understanding that objects have labels. Alternatively, infants’ performance could reflect their difficulty with tracking and integrating multiple multimodal cues. We contrasted these two accounts by looking at the effect of visual cues on word segmentation in adults and across childhood. We found that older (...) children benefitted from the regular visual cues, but younger children, who already knew that objects have labels, did not. Knowing that objects have labels was not enough to use visual cues as an aid for segmentation. These findings show that the ability to integrate multimodal cues develops during childhood, and it is not yet adult-like in children. (shrink)

Numerous studies have examined the acoustic correlates of sentential stress and its underlying linguistic functionality. However, the mechanism that connects stress cues to the listener's attentional processing has remained unclear. Also, the learnability versus innateness of stress perception has not been widely discussed. In this work, we introduce a novel perspective to the study of sentential stress and put forward the hypothesis that perceived sentence stress in speech is related to the unpredictability of prosodic features, thereby capturing the attention of (...) the listener. As predictability is based on the statistical structure of the speech input, the hypothesis also suggests that stress perception is a result of general statistical learning mechanisms. To study this idea, computational simulations are performed where temporal prosodic trajectories are modeled with an n-gram model. Probabilities of the feature trajectories are subsequently evaluated on a set of novel utterances and compared to human perception of stress. The results show that the low-probability regions of F0 and energy trajectories are strongly correlated with stress perception, giving support to the idea that attention and unpredictability of sensory stimulus are mutually connected. (shrink)

Acoustical changes in the prosody of mothers’ speech to infants are distinct and near universal. However, less is known about the visible properties of mothers’ infant-directed speech, and their relation to speech acoustics. Mothers’ head movements were tracked as they interacted with their infants using ID speech, and compared to movements accompanying their adult-directed speech. Movement measures along three dimensions of head translation, and three axes of head rotation were calculated. Overall, more head movement was found for ID than AD (...) speech, suggesting that mothers exaggerate their visual prosody in a manner analogous to the acoustical exaggerations in their speech. Regression analyses examined the relation between changing head position and changing acoustical pitch over time. Head movements and voice pitch were more strongly related in ID speech than in AD speech. When these relations were examined across time windows of different durations, stronger relations were observed for shorter time windows. However, the particular form of these more local relations did not extend or generalize to longer time windows. This suggests that the multimodal correspondences in speech prosody are variable in form, and occur within limited time spans. (shrink)

In language evolution research, the use of computational and experimental methods to investigate the emergence of structure in language is exploding. In this review, we look exclusively at work exploring the emergence of structure in speech, on both a categorical level, and a combinatorial level. We show that computational and experimental methods for investigating population-level processes can be effectively used to explore and measure the effects of learning, communication and transmission on the emergence of structure in speech. We also look (...) at work on child language acquisition as a tool for generating and validating hypotheses for the emergence of speech categories. Further, we review the effects of noise, iconicity and production effects. (shrink)