A New Look at Infant Problem-Solving: Using DeepLabCut to Investigate Exploratory Problem-Solving Approaches

Early social communication through music: State of the art and future perspectives

A growing body of research shows that the universal capacity for music perception and production emerges early in development. Possibly building on this predisposition, caregivers around the world often communicate with infants using songs or speech entailing song-like characteristics. This suggests that music might be one of the earliest developing and most accessible forms of interpersonal communication, providing a platform for studying early communicative behavior. However, little research has examined music in truly communicative contexts. The current work aims to facilitate the development of experimental approaches that rely on dynamic and naturalistic social interactions. We first review two longstanding lines of research that examine musical interactions by focusing either on the caregiver or the infant. These include defining the acoustic and non-acoustic features that characterize infant-directed (ID) music, as well as behavioral and neurophysiological research examining infants' processing of musical timing and pitch. Next, we review recent studies looking at early musical interactions holistically. This research focuses on how caregivers and infants interact using music to achieve co-regulation, mutual engagement, and increase affiliation and prosocial behavior. We conclude by discussing methodological, technological, and analytical advances that might empower a comprehensive study of musical communication in early childhood.

Infant Sitting and Multi-Directional Reaching Skill

We tested twenty-one 6- to 10-month-old infants with a wide range of sitting experience in forward and rightward reaching during unsupported sitting on the floor. Sessions were video-recorded for further behavioral and machine learning-based kinematic analyses. All infants, including novice sitters, successfully touched and grasped toys in both directions. Infant falls, hand support, and base of support changes were rare. Infants with more sitting experience showed better upright posture than novice sitters. However, we found no differences in trunk displacement or reaching kinematics between directions or across sitting experience. Thus, multi-directional reaching is functional in both novice and experienced infant sitters. We suggest that trunk and arm stability in sagittal and frontal planes is integral to learning to sit.

Dynamic sitting in infants: Limits of stability

BACKGROUND

Limits of stability-defined by the maximum distances a person is willing to reach without falling or changing the base of support-are measures of dynamic balance.

RESEARCH QUESTION

What are infants' sitting stability limits in the forward and right directions?

METHODS

Twenty-one 6- to 10-month old infants participated in this cross-sectional study. To incentivize infants to reach beyond arm's length, caregivers began by holding a toy close to their infants at shoulder height. Caregivers then moved the toy farther away as infants tried to reach for it until infants lost balance, placed their hands on the floor, or transitioned out of sitting. All sessions were conducted via Zoom™ and video-recorded for further analyses using DeepLabCut for 2D pose estimation and Datavyu to determine timings of the reach and to code infants' postural behaviors.

RESULTS

Infants' trunk excursions in the anterior-posterior plane (for forward reaches) and medio-lateral plane (for rightward reaches) represented their stability limits. Most infants ended the reach by returning to their original sitting position; however, infants with higher Alberta Infant Motor Scale (AIMS) scores transitioned out of sitting and infants with lower AIMS scores sometimes fell (mostly during rightward reaching). Trunk excursions were correlated with months of sitting experience. Rightward trunk excursions were also correlated with AIMS scores and age. Overall, infants' trunk excursions were larger in the forward than in the right direction, and such discrepancy was consistent across infants. Lastly, the more often infants adopted movement strategies with their legs (e.g., bending the knees), the greater the trunk excursion they attained.

SIGNIFICANCE

Sitting control entails learning to perceive the boundaries of stability limits and acquiring anticipatory postures to suit the needs of the task. Tests and interventions that target sitting stability limits could be beneficial for infants with or at risk of motor delays.

After 150 years of watching: is there a need for synthetic ethology?

The Darwinian idea of mental continuity is about 150 years old. Although nobody has strongly denied this evolutionary link, both conceptually and practically, relative slow advance has been made by ethology and comparative psychology to quantify mental evolution. Debates on the mechanistic interpretation of cognition often struggle with the same old issues (e.g., associationism vs cognitivism), and in general, experimental methods have made also relative slow progress since the introduction of the puzzle box. In this paper, we illustrate the prevailing issues using examples on 'mental state attribution' and 'perspective taking" and argue that the situation could be improved by the introduction of novel methodological inventions and insights. We suggest that focusing on problem-solving skills and constructing artificial agents that aim to correspond and interact with biological ones, may help to understand the functioning of the mind. We urge the establishment of a novel approach, synthetic ethology, in which researchers take on a practical stance and construct artificial embodied minds relying of specific computational architectures the performance of which can be compared directly to biological agents.

Online testing in developmental science: A guide to design and implementation

At present, most developmental psychology experiments use participants from a mere subsection of the world's population. Moreover, like other fields of psychology, many studies in developmental psychology suffer from low statistical power due to small samples and limited observations. Online testing holds promise as a way to achieve more representative and robust, better powered experiments. As participants do not have to visit in person, it is easier to access populations living further away from a developmental lab, enabling testing of more diverse populations (e.g., urban vs rural areas, various different nationalities or geographies), both within and beyond the researcher's home country. Furthermore, due to the codified nature of browser-based online testing, it is possible for multiple labs to carry out the exact same study, allowing for better replications. Because of these advantages, developmental researchers have started to move experiments online so that caregivers and their children can participate from their home environments. However, the transition from traditional lab testing to remote online testing brings many challenges. Laboratory studies of infant and child development are typically conducted under highly standardized conditions to control factors, such as distractors, distance to the screen, movement, and lighting, and often rely on specialized equipment for measuring behavior. In this chapter, we provide a guide for researchers considering online testing of a developmental population. The different sections comprise an overview of the decision-making processes and the state-of-the-art advances associated with, as well as tangible recommendations for, online data collection.