Four- and six-year-old children track a single meaning with both familiar and unfamiliar referents when the referent is clear: More evidence for propose-but-verify.

In word learning, learners need to identify the referent of words by leveraging the fact that the same word may co-occur with different sets of objects. This raises the question, what do children remember from "in the moment" that they can use for cross-situational learning? Furthermore, do children represent pictures of familiar animals versus drawings of non-existent novel objects as potential referents differently? This study examined these questions by creating learning scenarios with only two potential referents, requiring the least amount of memory to represent all co-present objects. Across three experiments (n > 250) with 4- and 6-year-old children, children reliably selected the intended referent from learning at test, though the learning of novel objects was better than familiar objects. When asked for a co-present object, children of all ages in the study performed at chance in all of the conditions. We discuss the developmental differences in cross-situational word learning capabilities with regard to representing different stimuli as potential referents. Importantly, all children used a propose-but-verify procedure for learning novel words even in the simplest of the learning scenarios given repeated exposure.

Statistical word segmentation succeeds given the minimal amount of exposure.

One of the first tasks in language acquisition is word segmentation, a process to extract word forms from continuous speech streams. Statistical approaches to word segmentation have been shown to be a powerful mechanism, in which word boundaries are inferred from sequence statistics. This approach requires the learner to represent the frequency of units from syllable sequences, though accounts differ on how much statistical exposure is required. In this study, we examined the computational limit with which words can be extracted from continuous sequences. First, we discussed why two occurrences of a word in a continuous sequence is the computational lower limit for this word to be statistically defined. Next, we created short syllable sequences that contained certain words either two or four times. Learners were presented with these syllable sequences one at a time, immediately followed by a test of the novel words from these sequences. We found that, with the computationally minimal amount of two exposures, words were successfully segmented from continuous sequences. Moreover, longer syllable sequences providing four exposures to words generated more robust learning results. The implications of these results are discussed in terms of how learners segment and store the word candidates from continuous sequences.

Perceptual intake explains variability in statistical word segmentation.

One of the first problems in language learning is to segment words from continuous speech. Both prosodic and distributional information can be useful, and it is an important question how the two types of information are integrated. In this paper, we propose that the distinction between input (the statistical properties of the syllable sequence), and intake (how learners perceptually represent the syllable sequence) is a useful framework to integrate different sources of information. We took a novel approach, observing how a large number of syllable sequences were segmented. These sequences had the same transitional probability information for finding word boundaries but different syllables in them. We found large variability in the performance of the segmentation task, suggesting that factors other than the statistical properties of sequences were at play. This variability was explored using the input/intake asymmetry framework, which predicted that factors that shaped the representation of different syllable sequences could explain the variability of learning. We examined two factors, the saliency of the rhythm in these syllable sequences and how familiar the novel word forms in the sequence were to the existing lexicon. Both factors explained the variance in the learnability of different sequences, suggesting that processing of the sequences shaped learning. The implications of these results to computational models of statistical learning and broader implications to language learning were discussed.

Effects of exogenous and endogenous cues on attentional orienting in deaf adults.

Adults who are deaf have been shown to have better visual attentional orienting than those with typical hearing, especially when the target is located in the periphery of the visual field. However, most studies in this population have assessed exogenous visual attention orienting (bottom-up processing of external cues) rather than endogenous visual attention orienting (top-down processing of internal cues). We used a target detection task to assess both types of visual attention orienting. A modified cue-target paradigm was adopted to assess the facilitation effects of exogenous and endogenous cues during short and long inter-stimulus intervals (ISI), using a 2 (Group: deaf/typically hearing) * 2 (Location: central/peripheral) * 2 (Cue Type: exogenous/endogenous) mixed factorial design. ANOVAs showed that both exogenous cues and endogenous cues can facilitate deaf adults' visual attentional orienting, and the facilitation effect of exogenous cues on attention orienting was significantly stronger for deaf participants than hearing participants. When the ISI was long, the effect was significantly stronger when the exogenous cue appeared in the periphery of the visual field. In the periphery, deaf adults benefited most from exogenous cues, whereas hearing adults benefited most from endogenous cues. The results suggest that not only exogenous cues but also endogenous cues can facilitate deaf adults' visual attentional orienting. However, the effect of exogenous cues appears to be greater, especially when the stimulus appears in the peripheral visual field.