How infants' reaches reveal principles of sensorimotor decision making

In Piaget's classical A-not-B-task, infants repeatedly make a sensorimotor decision to reach to one of two cued targets. Perseverative errors are induced by switching the cue from A to B, while spontaneous errors are unsolicited reaches to B when only A is cued. We argue that theoretical accounts of sensorimotor decision-making fail to address how motor decisions leave a memory trace that may impact future sensorimotor decisions. Instead, in extant neural models, perseveration is caused solely by the history of stimulation. We present a neural dynamic model of sensorimotor decision-making within the framework of Dynamic Field Theory, in which a dynamic instability amplifies fluctuations in neural activation into macroscopic, stable neural activation states that leave memory traces. The model predicts perseveration, but also a tendency to repeat spontaneous errors. To test the account, we pool data from several A-not-B experiments. A conditional probabilities analysis accounts quantitatively how motor decisions depend on the history of reaching. The results provide evidence for the interdependence among subsequent reaching decisions that is explained by the model, showing that by amplifying small differences in activation and affecting learning, decisions have consequences beyond the individual behavioural act

On the psychological origins of tool use

The ubiquity of tool use in human life has generated multiple lines of scientific and philosophical investigation to understand the development and expression of humans' engagement with tools and its relation to other dimensions of human experience. However, existing literature on tool use faces several epistemological challenges in which the same set of questions generate many different answers. At least four critical questions can be identified, which are intimately intertwined-(1) What constitutes tool use? (2) What psychological processes underlie tool use in humans and nonhuman animals? (3) Which of these psychological processes are exclusive to tool use? (4) Which psychological processes involved in tool use are exclusive to Homo sapiens? To help advance a multidisciplinary scientific understanding of tool use, six author groups representing different academic disciplines (e.g., anthropology, psychology, neuroscience) and different theoretical perspectives respond to each of these questions, and then point to the direction of future work on tool use. We find that while there are marked differences among the responses of the respective author groups to each question, there is a surprising degree of agreement about many essential concepts and questions. We believe that this interdisciplinary and intertheoretical discussion will foster a more comprehensive understanding of tool use than any one of these perspectives (or any one of these author groups) would (or could) on their own

Interactive brains:How infant cognition interacts with the dynamic social world

Research taking a cognitive neuroscience approach has shed light on social cognition during infancy. These studies have provided invaluable knowledge about how infants process social information, but a number of concepts regarding infant social cognition are often discussed based on research utilising rigidly controlled experimental paradigms where the role of infants is typically passive as an observer of stimuli. Increasing evidence suggests differences between the social cognitive processes that occurs when we act as observers of others (a ‘third-person’ perspective) and the processes that emerge when we are actively engaging with other people in an interactional context (a ‘second-person’ perspective) (e.g., Redcay and Schilbach, 2019; Siposova & Carpenter, 2019). Accordingly, there has been a growing recognition that we need a ‘second-person’ perspective, as compared to conventional “third-person” approach. The aim of the current thesis is to explore the interplay between infant cognition and the social world surrounding them, by moving research settings to a more naturalistic and dynamic one where infants are positioned as part of interaction. Towards this goal, Study 1 (Chapter 2) reviewed the current progress of “second-person” neuroscience research to evaluate the validity and robustness of simultaneous dual brain scanning techniques, often referred to as hyperscanning. The review identified large heterogeneity in reported effect sizes between published studies, suggesting the need to improve comparability of research, such as establishing standardised methods or promoting open science practices including code and data sharing to achieve higher reproducibility. This thesis then turned to research using various techniques from a conventional screen-based paradigm to a more dynamic setting, with the aim of building a stable platform towards second-person cognitive neuroscience approaches that investigate infant cognition while the infant actively interacts with other people. Study 2 (Chapter 3) explored how infants encode information differently from two adults who give gaze cues to a target object with different levels of accuracy. Whilst the study utilised a conventional event-related potential paradigm using screen-based stimuli, this paradigm could be adapted to enable future studies to investigate how infants’ social cognitive ability to discriminate reliable and unreliable informants can inform their subsequent behaviour observed in a social interactional behavioural task. Study 3 (Chapter 4) moved towards the use of more dynamic video stimuli and explored the neural processing of unexpected events. The study identified challenges in using dynamic perceptual inputs as stimuli. Study 4 (Chapter 5) transitioned into more naturalistic social contexts and analysed infant cognition while 10-month-old infants were faced with an adult demonstrating novel object labels in a live interaction. The study not only showed the feasibility of second-person neuroscientific research with infant participants, but also advanced our knowledge about infant word learning a step further, and demonstrated the trajectory from the encoding of semantic word information to its consolidation as knowledge. Study 5 (Chapter 6) also utilised a naturalistic interactional setting where infants were able to actively engage in a social task with an experimenter in a live manner, and aimed to identify systematic differences in neural activity between 9-month-old infants who make perseverative errors originally reported by Piaget (1954) and those who do not. This study was, to our knowledge, the first of its kind to validate the feasibility of utilising neurophysiological measures in this traditional interactive behavioural paradigm, in such a way that it does not interfere with the standard procedure. This thesis produced a series of studies which jointly demonstrate the potential for conducting research in a more dynamic setting that investigates infant social cognition taking a ‘second-person’ cognitive neuroscience approach to advance our knowledge about the intricate interaction between infant cognition, behaviour and the environment. We conclude this thesis by addressing the challenges of such an approach, to which we also attempt to propose solutions, as well as discussing future directions for the field