Gedeon O. Deak

In recent years, researchers in auditory perception have drawn renewed attention to the pervasive use of simplistic and artificial sound stimuli in the field, raising concerns about the generalizab...

Transcribing naturalistic caregiver-child interactions is a labor-intensive task in developmental research. While automatic speech recognition (ASR) models offer potential solutions, current ASR systems, including OpenAI’s Whisper, were primarily trained on adult-directed speech (ADS) and have not been systematically evaluated for infant-directed speech (IDS). IDS differs from ADS in prosody, phonetics, utterance structure, and lexical patterns, posing unique challenges for ASR transcription. In this study, we benchmarked Whisper’s transcription accuracy on a dataset of naturalistic caregiver infant recordings, comparing ASR-generated transcripts to human-annotated gold-standard transcriptions. We evaluated Whisper’s performance using word error rate (WER) and accuracy, and conducted a failure analysis to identify systematic errors made by Whisper, including utterance segmentation mismatches, high error rates in short and repetitive speech and inconsistent filler word handling. Results indicated that Whisper struggles with short, contextually ambiguous utterances and fails to reliably segment IDS utterances. Based on these results and early user experience, we propose a preliminary pipeline for integrating ASR technology with human transcription workflows to enhance the efficiency of processing large-scale naturalistic speech data in developmental research.

The process by which infants learn verbs through daily social interactions is not well-understood. This study investigated caregivers’ use of verbs, which have highly abstract meanings, during unscripted toy-play. We examined how verbs co-occurred with distributional and embodied factors including pronouns, caregivers’ manual actions, and infants’ locomotion, gaze, and object-touching. Object-action verbs were used significantly more often during caregiver-infant joint attention interactions. Movement and cognition verbs showed distinct co-occurrences with different contexts. Cognition and volition verbs were differentiated by pronouns. These findings provide evidence for how verb acquisition may be supported by the distributional and embodied contexts in caregiver-infant interactions.

Acquisition of visual attention‐following skills, notably gaze‐ and point‐following, contributes to infants' ability to share attention with caregivers, which in turn contributes to social learning and communication. However, the development of gaze‐ and point‐following in the first 18 months remains controversial, in part because of different testing protocols and standards. To address this, we longitudinally tested N = 43 low‐risk, North American middle‐class infants' tendency to follow gaze direction, pointing gestures, and gaze‐and‐point combinations. Infants were tested monthly from 4 to 12 months of age. To control motivational differences, infants were taught to expect contingent reward videos in the target locations. No‐cue trials were included to estimate spontaneous target fixation rates. A comparison sample (N = 23) was tested at 9 and 12 months to estimate practice effects. Results showed gradual increases in both gaze‐ and point‐following starting around 7 months, and modest month‐to‐month individual stability from 8 to 12 months. However, attention‐following did not exceed chance levels until after 6 months. Infants rarely followed cues to locations behind them, even at 12 months. Infants followed combined gaze‐and‐point cues more than gaze alone, and followed points at intermediate levels (not reliably different from the other cues). The comparison group's results showed that practice effects did not explain the age‐related increase in attention‐following. The results corroborate and extend previous findings that North American middle‐class infants' attention‐following in controlled laboratory settings increases slowly and incrementally between 6 and 12 months of age.Research Highlights: A longitudinal experimental study documented the emergence and developmental trajectories of North American middle‐class infants' visual attention‐following skills, including gaze‐following, point‐following, and gaze‐and‐point‐following. A new paradigm controlled for factors including motivation, attentiveness, and visual‐search baserates. Motor development was ruled out as a predictor or limiter of the emergence of attention‐following. Infants did not follow attention reliably until after 6 months, and following increased slowly from 7 to 12 months. Infants' individual trajectories showed modest month‐to‐month stability from 8 to 12 months of age.

Infant language learning depends on the distribution of co‐occurrences within language–between words and other words–and between language content and events in the world. Yet infant‐directed speech is not limited to words that refer to perceivable objects and actions. Rather, caregivers’ utterances contain a range of syntactic forms and expressions with diverse attentional, regulatory, social, and referential functions. We conducted a distributional analysis of linguistic content types at the utterance level, and demonstrated that a wide range of content types in maternal speech can be distinguished by their distribution in sequences of utterances and by their patterns of co‐occurrence with infants’ actions. We observed free‐play sessions of 38 12‐month‐old infants and their mothers, annotated maternal utterances for 10 content types, and coded infants’ gaze target and object handling. Results show that all content types tended to repeat in consecutive utterances, whereas preferred transitions between different content types reflected sequences from attention‐capturing to directing and then descriptive utterances. Specific content types were associated with infants’ engagement with objects (declaratives, descriptions, object names), with disengagement from objects (talk about attention, infant's name), and with infants’ gaze at the mother (affirmations). We discuss how structured discourse might facilitate language acquisition by making speech input more predictable and/or by providing clues about high‐level form‐function mappings.

Cognitive flexibility, the adaptation of representations and responses to new task demands, improves dramatically in early childhood. It is unclear, however, whether flexibility is a coherent, unitary cognitive trait, or is an emergent dimension of task-specific performance that varies across populations with divergent experiences. Three- to 5-year-old English-speaking U.S. children and Tswana-speaking South African children completed two distinct language-processing cognitive flexibility tests: the FIM-Animates, a word-learning test, and the 3DCCS, a rule-switching test. U.S. and South African children did not differ in word-learning flexibility but showed similar age-related increases. In contrast, U.S. preschoolers showed an age-related increase in rule-switching flexibility but South African children did not. Verbal recall explained additional variance in both tests but did not modulate the interaction between population sample (i.e., country) and task. We hypothesize that rule-switching flexibility might be more dependent upon particular kinds of cultural experiences, whereas word-learning flexibility is less cross-culturally variable.

Attention sharing provides an important context for infant learning, but it is not fully understood how infants respond to parents’ isolated or combined actions to shift from nonsharing to attention‐sharing states. To investigate this, we recorded unscripted toy‐play interactions of infants (3 to 11 months old, N = 35) and mothers at home, and coded attention‐related behaviors. These included infants’ and mothers’ visual fixations, and mothers’ attention‐directing actions including gaze shifts, pointing gestures, object manipulations, verbalizations, and object sounds. In addition, dyadic attention was continuously classified into one of seven states of shared or nonshared attention. Results showed that mothers usually produced a combination of attention‐directing cues within the 7 sec. before infants shifted their attention to match the mother's focus. Mothers’ cue combinations usually included object manipulation and either a gaze shift or a verbalization. Infants seldom looked at mothers’ faces and followed a very small proportion of isolated gaze shifts or pointing gestures. However, infants frequently shifted attention to watch mothers manipulate objects. The results indicate that during toy play, combinations of maternal attention‐specifying actions selectively elicit infants’ attention following.

Infants’ early motor actions help organize social interactions, forming the context of caregiver speech. We investigated changes across the first year in social contingencies between infant gaze and object exploration, and mothers’ speech. We recorded mother–infant object play at 4, 6, and 9 months, identifying infants’ and mothers’ gaze and hand actions, and mothers’ object naming and general utterances. Mothers named objects more when infants vocalized, looked at objects or the mother’s face, or handled multiple objects. As infants aged, their increasing object exploration created opportunities for caregiver contingencies and changed how gaze and hands accompany object naming over time.