Developing a self-reflective mind: infants' error-detection at 12 months predicts self-awareness at 18 months

Abstract

Self-reflection is central to human cognition and is arguably a defining feature of human consciousness. Yet, the mechanisms enabling our mind to reflect upon itself and to construct a conceptual sense of self remain poorly understood. This study brings empirical traction to the puzzle of self-reflection by studying human infants, across the period when a conceptual self is believed to emerge, from 12 to 18 months of age. Using a gaze-contingent match-to-sample paradigm with concurrent eye-tracking and EEG recordings, we find evidence of self-reflective capacities in 12-month-old infants: they exhibit a signature neural response of error-tracking (error-related negativity, ERN) after making incorrect as opposed to correct choices, and before receiving feedback. Remarkably, the magnitude of the ERN at 12 months developmentally predicted which infants will evidence a conceptual self-representation (mirror-self-recognition) 6 months later. This relationship was specific to internal error-monitoring (ERN), and not external feedback processing (FRN), and could not be explained by infants age or general cognitive development. Furthermore, we show that only the group of infants, who later evidenced self-representation, exhibited an ERN, while FRN was evidenced in both groups. Moreover, the same group of infants who evidenced self-representation and internal error monitoring also adapted their behaviour post-error, by slowing their decisions and increasing visual exploration following mistakes. Thus, error-detection, if available, can be utilised for adaptive information-seeking and decision-making as early as 12 months of age. The finding that internal error-monitoring not only precedes but developmentally predicts the emergence of self-representation strongly supports the proposal that infants error-monitoring and behavioural adjustments index rudimentary forms of metacognition. Moreover, these results point to the possibility that internal error-monitoring is functionally involved in building a conceptual self, thereby raising questions regarding possible factors modulating individuals sensitivity to own errors and consequently their conceptual representation of themselves as distinct epistemic agents.