Computational and Robotic Models of Early Language Development: A Review

We review computational and robotics models of early language learning and development. We first explain why and how these models are used to understand better how children learn language. We argue that they provide concrete theories of language learning as a complex dynamic system, complementing traditional methods in psychology and linguistics. We review different modeling formalisms, grounded in techniques from machine learning and artificial intelligence such as Bayesian and neural network approaches. We then discuss their role in understanding several key mechanisms of language development: cross-situational statistical learning, embodiment, situated social interaction, intrinsically motivated learning, and cultural evolution. We conclude by discussing future challenges for research, including modeling of large-scale empirical data about language acquisition in real-world environments. Keywords: Early language learning, Computational and robotic models, machine learning, development, embodiment, social interaction, intrinsic motivation, self-organization, dynamical systems, complexity.Comment: to appear in International Handbook on Language Development, ed. J. Horst and J. von Koss Torkildsen, Routledg

Comparative cognition for conservationists.

Every animal occupies a unique cognitive world based on its sensory capacities, and attentional and learning biases. Behaviour results from the interaction of this cognitive world with the environment. As humans alter environments, cognitive processes ranging from perceptual processes to learned behaviour govern animals' reactions. By harnessing animals' perceptual biases and applying insights from cognitive theory, we can purposefully alter cues to reduce maladaptive responses and shape behaviour. Despite the fundamental connection between cognition and behaviour, the breadth of cognitive theory is underutilised in conservation practice. Bridging these disciplines could augment existing conservation efforts targeting animal behaviour. We outline relevant principles of perception and learning, and develop a step-by-step process for applying aspects of cognition towards specific conservation issues.We would like to thank Nick Davies and several anonymous reviewers for helpful discussions and comments on the manuscript, and Edward Legg and Ljerka Ostojic for feedback on the figures. A.L.G. received generous support from the Gates-Cambridge Trust; A.T. is funded by a BBSRC David Phillips Fellowship (BB/H021817/1); B.P. is funded by a Zukerman Research Fellowship at King's College.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.tree.2014.06.00

Eligibility Traces and Plasticity on Behavioral Time Scales: Experimental Support of neoHebbian Three-Factor Learning Rules

Most elementary behaviors such as moving the arm to grasp an object or walking into the next room to explore a museum evolve on the time scale of seconds; in contrast, neuronal action potentials occur on the time scale of a few milliseconds. Learning rules of the brain must therefore bridge the gap between these two different time scales. Modern theories of synaptic plasticity have postulated that the co-activation of pre- and postsynaptic neurons sets a flag at the synapse, called an eligibility trace, that leads to a weight change only if an additional factor is present while the flag is set. This third factor, signaling reward, punishment, surprise, or novelty, could be implemented by the phasic activity of neuromodulators or specific neuronal inputs signaling special events. While the theoretical framework has been developed over the last decades, experimental evidence in support of eligibility traces on the time scale of seconds has been collected only during the last few years. Here we review, in the context of three-factor rules of synaptic plasticity, four key experiments that support the role of synaptic eligibility traces in combination with a third factor as a biological implementation of neoHebbian three-factor learning rules

Predicting human behavior in smart environments: theory and application to gaze prediction

Predicting human behavior is desirable in many application scenarios in smart environments. The existing models for eye movements do not take contextual factors into account. This addressed in this thesis using a systematic machine-learning approach, where user profiles for eye movements behaviors are learned from data. In addition, a theoretical innovation is presented, which goes beyond pure data analysis. The thesis proposed the modeling of eye movements as a Markov Decision Processes. It uses Inverse Reinforcement Learning paradigm to infer the user eye movements behaviors

A Comparison of Bidirectional Naming for Familiar and Non-Familiar Stimuli and the Effects of a Repeated Probe Procedure for First Grade Students

The experimenter conducted three experiments to compare incidental language acquisition of familiar and non-familiar stimuli, and asses the effects of specific pairing experiences on the emergence of bidirectional naming (BiN) for familiar and non-familiar stimuli. In Experiment I the experimenter assessed the numbers of accurate untaught listener and speaker responses for familiar and non-familiar stimuli emitted by 20 first-grade participants following incidental naming experiences. A statistical comparison of the results using a dependent paired samples t-tests revealed significant differences across familiar and non-familiar stimuli for: (a) listener responses, (b) speaker tact responses, and (c) speaker intraverbal tact responses. In Experiment II, the experimenter tested the effectiveness of a repeated probe procedure on the emergence of BiN for familiar and non-familiar stimuli using a combined multiple probe and simultaneous treatment design. Six participants were selected from Experiment I based on their absence of BiN for non-familiar stimuli. The experimenter implemented a repeated probe intervention procedure across two treatment conditions: (1) non-familiar stimuli sets and (2) mixed (non-familiar and familiar) stimuli sets. Following each intervention phase, post-intervention naming probe results demonstrated increased numbers of accurate untaught listener and speaker responses for familiar and non-familiar stimuli by all participants. Time constraints of the school year limited completion of the intervention for 2 participant dyads. Findings suggested the potential effectiveness of the repeated probe procedure. Experiment III was a systematic replication of Experiment II with 6 different participants. Results demonstrated the emergence of: (a) BiN for non-familiar stimuli by five participants; and (b) BiN for familiar stimuli by all participants who demonstrated absence during pre-intervention probe sessions. Findings from Experiments II and III suggested that the repeated probe procedure effectively functioned as a conditioning procedure for the emergence of conditioned reinforcement for observing responses to visual and vocal familiar and non-familiar stimuli. That is, the repeated probe procedure shifted the reinforcement effects of conditioned stimuli to previously neutral stimuli, bringing one’s observing responses under a new stimulus control. This stimulus control (i.e., reinforcement effects) embedded within functioned to select out the participant’s observing responses during incidental naming experiences

The Effects of Naming Experiences and Properties of Visual Stimuli on Language Acquisition and the Relationship between Curiosity and Naming

Children typically acquire language rapidly during their first few years of life. Their rates and levels of proficiency vary, but it is clear that the development of one’s language repertoire impacts academic outcomes and future success across many domains. There are both genetic and environmental factors that affect and contribute to one’s development. For children whose vocal verbal behavior is less well developed, it is imperative that we continue to develop and implement tactics and procedures to intervene in order to accelerate their language development. Researchers have identified Naming as a critical verbal developmental capability that allows one to learn language incidentally. Are there different types of Naming capabilities? Do properties of stimuli affect language acquisition? Does the Naming repertoire relate to children’s level of curiosity about the world around them? In the 3 experiments that follow, I examined the effects of 2 types of Naming experiences and varying properties of visual stimuli on measures of Naming. In Experiments 2 and 3, I also conducted measures of curiosity to assess the possibility of a relationship between Naming and question asking. In my first experiment there were 31 participants. I investigated the effects of match-to-sample and exclusion Naming experiences on incidental acquisition of listener and speaker responses in both adults without disabilities and youth with disabilities. I examined the differences between the 2 age groups and Naming experiences. The adult means of listener and speaker responses were greater than the youth means. All adults met criterion for Naming with the match-to-sample experience, and 9 of 14 adults also achieved criterion levels with the unfamiliar stimuli following the exclusion Naming experience. The adult group’s results showed that the group’s Naming repertoire was fairly balanced for listener responses across the Naming experiences with minimal variability, and its speaker repertoire was not as balanced. The youth group’s results demonstrated similar levels of variability across both topographies. The effect of the Naming experience was significant for speaker responses. In the second experiment, I implemented an intervention to try to establish unfamiliar stimuli as reinforcers to test its effects on the 2 types of Naming probes and curiosity measures in 6 elementary age children with disabilities. There were some effects from the treatment, but following 2 intervention conditions none of the participants met criteria for Naming. The participants’ numbers of accurate listener responses were greater than their speaker responses. In Experiment 3, I conducted tests for curiosity and Naming with sets of stimuli that had varying levels of familiarity and complexity for 9 preschool age children with and without disabilities. As with the first 2 experiments, the numbers of listener responses for participants were greater than their speaker responses, and there was more variability in the speaker responses compared to the listener responses. The results suggested that the type of Naming experience or the familiarity level of the visual stimuli alone did not appear to influence the dependent variables, but rather that there may be an interaction among the independent variables. The means of responses were greater with more familiar stimuli following match-to-sample experiences whereas the means were greater with less familiar stimuli following the exclusionary Naming experiences. The results of the 3 experiments affirmed the independence of the listener and speaker components of Naming and suggest that the demonstration of Naming with unknown, unfamiliar types of stimuli may be a type of Naming capability that may not be present in all individuals who demonstrate Naming with unknown, familiar stimuli

Encoding of mechanical nociception differs in the adult and infant brain

Newborn human infants display robust pain behaviour and specific cortical activity following noxious skin stimulation, but it is not known whether brain processing of nociceptive information differs in infants and adults. Imaging studies have emphasised the overlap between infant and adult brain connectome architecture, but electrophysiological analysis of infant brain nociceptive networks can provide further understanding of the functional postnatal development of pain perception. Here we hypothesise that the human infant brain encodes noxious information with different neuronal patterns compared to adults. To test this we compared EEG responses to the same time-locked noxious skin lance in infants aged 0-19 days (n = 18, clinically required) and adults aged 23-48 years (n = 21). Time-frequency analysis revealed that while some features of adult nociceptive network activity are present in infants at longer latencies, including beta-gamma oscillations, infants display a distinct, long latency, noxious evoked 18-fold energy increase in the fast delta band (2-4 Hz) that is absent in adults. The differences in activity between infants and adults have a widespread topographic distribution across the brain. These data support our hypothesis and indicate important postnatal changes in the encoding of mechanical pain in the human brain