Eliciting imitation in early infancy

Faces and Voices Processing in Human and Primate Brains: Rhythmic and Multimodal Mechanisms Underlying the Evolution and Development of Speech

While influential works since the 1970s have widely assumed that imitation is an innate skill in both human and non-human primate neonates, recent empirical studies and meta-analyses have challenged this view, indicating other forms of reward-based learning as relevant factors in the development of social behavior. The visual input translation into matching motor output that underlies imitation abilities instead seems to develop along with social interactions and sensorimotor experience during infancy and childhood. Recently, a new visual stream has been identified in both human and non-human primate brains, updating the dual visual stream model. This third pathway is thought to be specialized for dynamics aspects of social perceptions such as eye-gaze, facial expression and crucially for audio-visual integration of speech. Here, we review empirical studies addressing an understudied but crucial aspect of speech and communication, namely the processing of visual orofacial cues (i.e., the perception of a speaker's lips and tongue movements) and its integration with vocal auditory cues. Along this review, we offer new insights from our understanding of speech as the product of evolution and development of a rhythmic and multimodal organization of sensorimotor brain networks, supporting volitional motor control of the upper vocal tract and audio-visual voices-faces integration.

Sharing Experiences in Infancy: From Primary Intersubjectivity to Shared Intentionality

We contrast two theses that make different assumptions about the developmental onset of human-unique sociality. The primary intersubjectivity thesis (PIT) argues that humans relate to each other in distinct ways from the beginning of life, as is shown by newborns' participation in face-to-face encounters or "primary intersubjectivity." According to this thesis, humans' innate relational capacity is the seedbed from which all subsequent social-emotional and social-cognitive developments continuously emerge. The shared intentionality thesis (SIT) states that human-unique forms of interaction develop at 9-12 months of age, when infants put their heads together with others in acts of object-focused joint attention and simple collaborative activities. According to this thesis, human-unique cognition emerges rapidly with the advent of mind-reading capacities that evolved specifically for the purpose of coordination. In this paper, we first contrast the two theses and then sketch the outlines of an account that unifies their strengths. This unified account endorses the PIT's recognition of the fundamental importance of primary intersubjectivity. Any act of sharing experiences is founded on the communicative capacity that is already displayed by young infants in primary intersubjectivity. At the same time, we question the PIT's interpretation that dyadic encounters have the triadic structure of joint attention. Lastly, we draw on empirical work on the development of joint attention, imitation, and social referencing that serves as evidence that primary intersubjectivity continuously unfolds into the capacity for triadic joint attention.

The development of body representations: an associative learning account

Representing one's own body is of fundamental importance to interact with our environment, yet little is known about how body representations develop. One account suggests that the ability to represent one's own body is present from birth and supports infants' ability to detect similarities between their own and others' bodies. However, in recent years evidence has been accumulating for alternative accounts that emphasize the role of multisensory experience obtained through acting and interacting with our own body in the development of body representations. Here, we review this evidence, and propose an integrative account that suggests that through experience, infants form multisensory associations that facilitate the development of body representations. This associative account provides a coherent explanation for previous developmental findings, and generates novel hypotheses for future research.

Individual differences in neonatal "imitation" fail to predict early social cognitive behaviour

The influential hypothesis that humans imitate from birth - and that this capacity is foundational to social cognition - is currently being challenged from several angles. Most prominently, the largest and most comprehensive longitudinal study of neonatal imitation to date failed to find evidence that neonates copied any of nine actions at any of four time points (Oostenbroek et al., [2016] Current Biology, 26, 1334-1338). The authors of an alternative and statistically liberal post-hoc analysis of these same data (Meltzoff et al., [2017] Developmental Science, 21, e12609), however, concluded that the infants actually did imitate one of the nine actions: tongue protrusion. In line with the original intentions of this longitudinal study, we here report on whether individual differences in neonatal "imitation" predict later-developing social cognitive behaviours. We measured a variety of social cognitive behaviours in a subset of the original sample of infants (N = 71) during the first 18 months: object-directed imitation, joint attention, synchronous imitation and mirror self-recognition. Results show that, even using the liberal operationalization, individual scores for neonatal "imitation" of tongue protrusion failed to predict any of the later-developing social cognitive behaviours. The average Spearman correlation was close to zero, mean r_s  = 0.027, 95% CI [-0.020, 0.075], with all Bonferroni adjusted p values > .999. These results run counter to Meltzoff et al.'s rebuttal, and to the existence of a "like me" mechanism in neonates that is foundational to human social cognition.

Re-analysis of data reveals no evidence for neonatal imitation in rhesus macaques

Over the past decade, a growing number of publications have claimed to provide evidence for the existence and function of neonatal imitation in rhesus macaques. Here I show that there is in fact no empirical basis for these claims. Studies of the phenomenon have consistently failed to implement the gold standard cross-target analytical approach, which controls for increases in matching responses that may not be a function of the specific modelled behaviour. Critically, a pre-registered re-analysis of the entire set of existing data using this cross-target approach shows that macaque neonates have failed to produce matching tongue protrusion or lipsmacking responses at levels greater than chance. Furthermore, there is no evidence for intra-individual consistency in 'imitative' responses across different actions, as imitation scores for the two actions are negatively correlated with each other. Macaque tongue protrusion and lipsmacking responses may vary as a function of general factors that fluctuate over testing sessions, rather than as a function of the specific model or of between-individual variations in imitative tendencies.

Enabling Confirmatory Secondary Data Analysis by Logging Data Checkout

As more researchers make their data sets openly available, the potential of secondary data analysis to address new questions increases. However, the distinction between primary and secondary data analysis is unnecessarily confounded with the distinction between confirmatory and exploratory research. We propose a framework, akin to library-book checkout records, for logging access to data sets in order to support confirmatory analysis when appropriate. This system would support a standard form of preregistration for secondary data analysis, allowing authors to demonstrate that their plans were registered prior to data access. We discuss the critical elements of such a system, its strengths and limitations, and potential extensions.