Brock Ferguson

Communicative signals support abstract rule learning by 7-month-old infants

The mechanisms underlying the discovery of abstract rules like those found in natural language may be evolutionarily tuned to speech, according to previous research. When infants hear speech sounds, they can learn rules that govern their combination, but when they hear non-speech sounds such as sine-wave tones, they fail to do so. Here we show that infants’ rule learning is not tied to speech per se, but is instead enhanced more broadly by communicative signals. In two experiments, infants succeeded in learning and generalizing rules from tones that were introduced as if they could be used to communicate. In two control experiments, infants failed to learn the very same rules when familiarized to tones outside of a communicative exchange. These results reveal that infants’ attention to social agents and communication catalyzes a fundamental achievement of human learning.

The precision of 12-month-old infants’ link between language and categorization predicts vocabulary size at 12 and 18 months

Infants’ initially broad links between language and object categories are increasingly tuned, becoming more precise by the end of their first year. In a longitudinal study, we asked whether individual differences in the precision of infants’ links at 12 months of age are related to vocabulary development. We found that, at 12 months, infants who had already established a precise link between labels and categories understood more words than those whose link was still broad. Six months later, this advantage held: At 18 months, infants who had demonstrated a precise link at 12 months knew and produced more words than did infants who had demonstrated a broad link at 12 months. We conclude that individual differences in the precision of 12-month-old infants’ links between language and categories provide a reliable window into their vocabulary development. We consider several causal explanations of this relation.

Very young infants learn abstract rules in the visual modality

Abstracting the structure or ‘rules’ underlying observed patterns is central to mature cognition, yet research with infants suggests this far-reaching capacity is initially restricted to certain stimuli. Infants successfully abstract rules from auditory sequences (e.g., language), but fail when the same rules are presented as visual sequences (e.g., shapes). We propose that this apparent gap between rule learning in the auditory and visual modalities reflects the distinct requirements of the perceptual systems that interface with cognition: The auditory system efficiently extracts patterns from sequences structured in time, but the visual system best extracts patterns from sequences structured in space. Here, we provide the first evidence for this proposal with adults in an abstract rule learning task. We then reveal strong developmental continuity: infants as young as 3 months of age also successfully learn abstract rules in the visual modality when sequences are structured in space. This provides the earliest evidence to date of abstract rule learning in any modality.

When Veps Cry: Two-Year-Olds Efficiently Learn Novel Words from Linguistic Contexts Alone

ABSTRACT We assessed 24-month-old infants’ lexical processing efficiency for both novel and familiar words. Prior work documented that 19-month-olds successfully identify referents of familiar words (e.g., The dog is so little) as well as novel words whose meanings were informed only by the surrounding sentence (e.g., The vep is crying), but that the speed with which they identify the referents of novel words lagged far behind that for familiar words. Here we take a developmental approach, extending this work to 24-month-olds. By comparing the performance of 19- and 24-month-olds directly, we document that during this period of rapid vocabulary growth, infants make significant processing gains for both familiar and novel words. We also offer the first evidence to date that, at both 19- and 24-months, the number of verbs infants know predicts their ability to use known verbs to learn novel nouns. These results reveal that 24-month-olds can efficiently learn novel words just by listening to the conversations around them.

The profile of abstract rule learning in infancy: Meta-analytic and experimental evidence

Abstract Everyone agrees that infants possess general mechanisms for learning about the world, but the existence and operation of more specialized mechanisms is controversial. One mechanism—rule learning—has been proposed as potentially specific to speech, based on findings that 7‐month‐olds can learn abstract repetition rules from spoken syllables (e.g. ABB patterns: wo‐fe‐fe, ga‐tu‐tu…) but not from closely matched stimuli, such as tones. Subsequent work has shown that learning of abstract patterns is not simply specific to speech. However, we still lack a parsimonious explanation to tie together the diverse, messy, and occasionally contradictory findings in that literature. We took two routes to creating a new profile of rule learning: meta‐analysis of 20 prior reports on infants’ learning of abstract repetition rules (including 1,318 infants in 63 experiments total), and an experiment on learning of such rules from a natural, non‐speech communicative signal. These complementary approaches revealed that infants were most likely to learn abstract patterns from meaningful stimuli. We argue that the ability to detect and generalize simple patterns supports learning across domains in infancy but chiefly when the signal is meaningfully relevant to infants’ experience with sounds, objects, language, and people.

Social touch interacts with infants’ learning of auditory patterns

Highlights • Infants use intersensory redundancy provided by social touch to learn auditory patterns.• There is wide variation in the frequency of different patterns of touch from caregivers.• Less frequent patterns of touch may be more likely to enhance attention and learning.• The findings suggest that infants track patterns of touch in naturalistic input from caregivers.