A neural network model of curiosity-driven categorization

Infants are curious learners who drive their own cognitive development by imposing structure on their learning environments as they explore. Understanding the mechanisms underlying this curiosity is therefore critical to our understanding of development. However, very few studies have examined the role of curiosity in infants’ learning, and in particular, their categorization; what structure infants impose on their own environment and how this affects learning is therefore unclear. The results of studies in which the learning environment is structured a priori are contradictory: while some suggest that complexity optimizes learning, others suggest that minimal complexity is optimal, and still others report a Goldilocks effect by which intermediate difficulty is best. We used an autoencoder network to capture empirical data in which 10-month old infants’ categorization was supported by maximal complexity [1]. When we allowed the same model to choose stimulus sequences based on a “curiosity” metric which took into account the model’s internal states as well as stimulus features, categorization was better than selection based solely on stimulus characteristics. The sequences of stimuli chosen by the model in the curiosity condition showed a Goldilocks effect with intermediate complexity. This study provides the first computational investigation of curiosity-based categorization, and points to the importance characterizing development as emerging from the relationship between the learner and its environment

The role of ostensive-referential communication in action understanding during infancy and early childhood

This thesis investigates how the presence of communicative signals such as direct gaze and infant-directed speech might help infants and young children to under- stand, anticipate, and segment actions. For this, the thesis draws upon a range of methodologies, such as electroencephalography (Chapter 2), eye tracking, pupil dilation (both Chapter 3), and behavioural research (Chapter 4). Chapter 2 and 3 both investigate whether the presence of communicative signals, such as infant directed speech and direct gaze, increase infants’ under- standing of actions as meaningful. The ERP experiments on 9-month-old infants reported in Chapter 2 found limited evidence that the presence of communica- tive signals enhances the N400 response, a correlate of semantic understanding. Furthermore, there is limited evidence of a complex response taking into account the presence of communication and action congruency in the Pb component in the second experiment, in which referential signals were added and the structure of the presentation was changed. Meanwhile, Chapter 3 found no evidence that communicative signals enhance anticipatory looking in 7-month-old children. Chapter 2 and 3 also investigate the possibility that communication enhances arousal. However, neither the Nc component reported in Chapter 2, nor the Pupillary Light Reflex investigated in Chapter 3 provided evidence in support of this hypothesis