Internal biases are linked to disrupted cue combination in children and adults.

Cue combination describes the use of two sensory cues together to increase perceptual precision. Internal relative bias describes a situation in which two cues to the same state of the world are perceived as signaling different states of the world on average. Current theory and evidence have difficulty accounting for many instances where cue combination is absent, such as in children under 10 years old, and in a variety of tasks. Here we show that internal relative biases between cues could be a key explanatory factor. Experiment 1, studying children's three-dimensional (slant) perception via disparity and texture, found a negative cross-sectional correlation between internal relative bias and cue combination behavior in 7- to 10-year-olds. Strikingly, children who had below-median levels of internal relative bias were able to combine cues, unlike the typical result for that age range. Experiment 2, studying adults' visual-auditory localization, found that cue combination behavior increased after an intervention designed to decrease internal relative bias. We interpret this as strong but preliminary evidence that internal relative bias can disrupt cue combination behavior. This provides a plausible mechanism to explain why children under 10 generally do not combine cues and why the audiovisual cue combination is so inconsistent in adults. Moving forward, we suggest that researchers who fail to find an expected cue combination effect should further investigate the possibility of issues with internal relative bias. Decreasing internal relative bias may also be an important goal for rehabilitation and sensory substitution or augmentation approaches to promoting efficient multisensory perception.

The Developing Bodily Self: How Posture Constrains Body Representation in Childhood.

Adults' body representation is constrained by multisensory information and knowledge of the body such as its possible postures. This study (N = 180) tested for similar constraints in children. Using the rubber hand illusion with adults and 6- to 7-year olds, we measured proprioceptive drift (an index of hand localization) and ratings of felt hand ownership. The fake hand was either congruent or incongruent with the participant's own. Across ages, congruency of posture and visual-tactile congruency yielded greater drift toward the fake hand. Ownership ratings were higher with congruent visual-tactile information, but unaffected by posture. Posture constrains body representation similarly in children and adults, suggesting that children have sensitive, robust mechanisms for maintaining a sense of bodily self.

Exploring the Influence of Object Similarity and Desirability on Children's Ownership Identification and Preferences in Autism and Typical Development.

This study investigated how ownership identification accuracy and object preferences in children with autism spectrum disorder (ASD) are influenced by visual distinctiveness and relative desirability. Unlike typically developing (TD) children matched on receptive language (M age equivalents: 58.8-59.9 months), children with ASD had difficulty identifying another person's property when object discriminability was low and identifying their own relatively undesirable objects. Children with ASD identified novel objects designated to them with no greater accuracy than objects designated to others, and associating objects with the self did not bias their preferences. We propose that, due to differences in development of the psychological self, ownership does not increase the attentional or preferential salience of objects for children with ASD.

Multisensory perception and decision-making with a new sensory skill.

It is clear that people can learn a new sensory skill-a new way of mapping sensory inputs onto world states. It remains unclear how flexibly a new sensory skill can become embedded in multisensory perception and decision-making. To address this, we trained typically sighted participants (N = 12) to use a new echo-like auditory cue to distance in a virtual world, together with a noisy visual cue. Using model-based analyses, we tested for key markers of efficient multisensory perception and decision-making with the new skill. We found that 12 of 14 participants learned to judge distance using the novel auditory cue. Their use of this new sensory skill showed three key features: (a) It enhanced the speed of timed decisions; (b) it largely resisted interference from a simultaneous digit span task; and (c) it integrated with vision in a Bayes-like manner to improve precision. We also show some limits following this relatively short training: Precision benefits were lower than the Bayes-optimal prediction, and there was no forced fusion of signals. We conclude that people already embed new sensory skills in flexible multisensory perception and decision-making after a short training period. A key application of these insights is to the development of sensory augmentation systems that can enhance human perceptual abilities in novel ways. The limitations we reveal (sub-optimality, lack of fusion) provide a foundation for further investigations of the limits of these abilities and their brain basis. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Lifelong learning of cognitive styles for physical problem-solving: The effect of embodied experience.

'Embodied cognition' suggests that our bodily experiences broadly shape our cognitive capabilities. We study how embodied experience affects the abstract physical problem-solving styles people use in a virtual task where embodiment does not affect action capabilities. We compare how groups with different embodied experience - 25 children and 35 adults with congenital limb differences versus 45 children and 40 adults born with two hands - perform this task, and find that while there is no difference in overall competence, the groups use different cognitive styles to find solutions. People born with limb differences think more before acting but take fewer attempts to reach solutions. Conversely, development affects the particular actions children use, as well as their persistence with their current strategy. Our findings suggest that while development alters action choices and persistence, differences in embodied experience drive changes in the acquisition of cognitive styles for balancing acting with thinking.

The role of hand size in body representation: a developmental investigation.

Knowledge of one's own body size is a crucial facet of body representation, both for acting on the environment and perhaps also for constraining body ownership. However, representations of body size may be somewhat plastic, particularly to allow for physical growth in childhood. Here we report a developmental investigation into the role of hand size in body representation (the sense of body ownership, perception of hand position, and perception of own-hand size). Using the rubber hand illusion paradigm, this study used different fake hand sizes (60%, 80%, 100%, 120% or 140% of typical size) in three age groups (6- to 7-year-olds, 12- to 13-year-olds, and adults; N = 229). We found no evidence that hand size constrains ownership or position: participants embodied hands which were both larger and smaller than their own, and indeed judged their own hands to have changed size following the illusion. Children and adolescents embodied the fake hands more than adults, with a greater tendency to feel their own hand had changed size. Adolescents were particularly sensitive to multisensory information. In sum, we found substantial plasticity in the representation of own-body size, with partial support for the hypothesis that children have looser representations than adults.

My Virtual Self: The Role of Movement in Children's Sense of Embodiment.

There are vast potential applications for children's entertainment and education with modern virtual reality (VR) experiences, yet we know very little about how the movement or form of such a virtual body can influence children's feelings of control (agency) or the sensation that they own the virtual body (ownership). In two experiments, we gave a total of 197 children aged 4-14 years a virtual hand which moved synchronously or asynchronously with their own movements and had them interact with a VR environment. We found that movement synchrony influenced feelings of control and ownership at all ages. In Experiment 1 only, participants additionally felt haptic feedback either congruently, delayed or not at all - this did not influence feelings of control or ownership. In Experiment 2 only, participants used either a virtual hand or non-human virtual block. Participants embodied both forms to some degree, provided visuomotor signals were synchronous (as indicated by ownership, agency, and location ratings). Yet, only the hand in the synchronous movement condition was described as feeling like part of the body, rather than like a tool (e.g., a mouse or controller). Collectively, these findings highlight the overall dominance of visuomotor synchrony for children's own-body representation; that children can embody non-human forms to some degree; and that embodiment is also somewhat constrained by prior expectations of body form.

An adaptive cue selection model of allocentric spatial reorientation.

After becoming disoriented, an organism must use the local environment to reorient and recover vectors to important locations. A new theory, adaptive combination, suggests that the information from different spatial cues is combined with Bayesian efficiency during reorientation. To test this further, we modified the standard reorientation paradigm to be more amenable to Bayesian cue combination analyses while still requiring reorientation in an allocentric (i.e., world-based, not egocentric) frame. Twelve adults and 20 children at ages 5 to 7 years old were asked to recall locations in a virtual environment after a disorientation. Results were not consistent with adaptive combination. Instead, they are consistent with the use of the most useful (nearest) single landmark in isolation. We term this adaptive selection. Experiment 2 suggests that adults also use the adaptive selection method when they are not disoriented but are still required to use a local allocentric frame. This suggests that the process of recalling a location in the allocentric frame is typically guided by the single most useful landmark rather than a Bayesian combination of landmarks. These results illustrate that there can be important limits to Bayesian theories of the cognition, particularly for complex tasks such as allocentric recall. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Comparing cross-situational word learning, retention, and generalisation in children with autism and typical development.

Word learning is complicated by referential ambiguity - there are often multiple potential targets for a newly-heard word. While typically developing (TD) children can accurately infer word meanings from cross-situational statistics, specific difficulties tracking word-object co-occurrences may contribute to language impairments in autism spectrum disorder (ASD). Here, we investigate cross-situational word learning as an integrated system including mapping, retention, and generalisation in both typical development and autism. In Study 1, children with ASD were as accurate at disambiguating the meanings of novel words from statistical correspondences as TD controls matched on receptive vocabulary. In Study 2, both populations spontaneously utilised social and non-social attentional cues to facilitate and accelerate their mapping of word-referent relationships. Across Studies 1 and 2, both groups retrieved and generalised word-referent representations with impressive and comparable accuracy. Although children with ASD performed very similarly to TD children on measures of learning accuracy, they were significantly slower to identify correct referents under both cued and non-cued learning conditions. These findings indicate that mechanisms supporting cross-situational word learning, and the relationships between them, are not qualitatively atypical in language-delayed children with ASD. However, the increased time required to generate correct responses suggests that these mechanisms may be less efficient, potentially impacting learning in natural environments where visual and auditory stimuli are presented rapidly. Our data support claims that word learning in the longer term is driven by the gradual accumulation of word-object associations over multiple learning instances and could potentially inform the development of interventions designed to scaffold word learning.

The Difficulty of Effectively Using Allocentric Prior Information in a Spatial Recall Task.

Prior information represents the long-term statistical structure of an environment. For example, colds develop more often than throat cancer, making the former a more likely diagnosis for a sore throat. There is ample evidence for effective use of prior information during a variety of perceptual tasks, including the ability to recall locations using an egocentric (self-based) frame. However, it is not yet known if people can use prior information effectively when using an allocentric (world-based) frame. Forty-eight adults were shown sixty sets of three target locations in a sparse virtual environment with three beacons. The targets were drawn from one of four prior distributions. They were then asked to point to the targets after a delay and a change in perspective. While searches were biased towards the beacons, we did not find any evidence that participants successfully exploited the prior distributions of targets. These results suggest that allocentric reasoning does not conform to normative Bayesian models: we saw no evidence for use of priors in our cognitively-complex (allocentric) task, unlike in previous, simpler (egocentric) recall tasks. It is possible that this reflects the high biological cost of processing precise allocentric information.

Investigating the relationship between fast mapping, retention, and generalisation of words in children with autism spectrum disorder and typical development.

While many studies have investigated how autism spectrum disorder (ASD) impacts how children identify the meanings of new words, this task alone does not constitute learning. Here we investigate fast (referent selection) and slow (retention, generalisation) word learning processes as an integrated system and explore relationships between these mechanisms in ASD and typical development. In Study 1, children with ASD and typically developing (TD) children matched on receptive vocabulary utilised mutual exclusivity to identify referents of unfamiliar words, but showed substantially reduced accuracy on delayed retention and generalisation trials. Thus, Study 2 investigated whether re-directing children's attention to target objects following referent selection would enhance delayed retention. Participants received either social feedback (target objects were labelled and highlighted via social cues) or non-social feedback (target objects were labelled and highlighted via a flashing light). In both conditions, children with ASD were less accurate in their use of mutual exclusivity to fast-map novel words than TD children. However, children with ASD who received social feedback responded more accurately on delayed retention and generalisation trials than TD controls, and children with ASD who received non-social feedback or no feedback (in Study 1). Our findings imply that fundamental word learning mechanisms, and the relationships between them, are not qualitatively different in ASD. We argue that ASD may affect the efficiency of these mechanisms by disrupting children's intake of linguistic input in natural environments, but difficulties may be mitigated by presenting visual and auditory stimuli in a way that appeals to the population's strengths.

Sensory cue combination in children under 10 years of age.

Cue combination occurs when two independent noisy perceptual estimates are merged together as a weighted average, creating a unified estimate that is more precise than either single estimate alone. Surprisingly, this effect has not been demonstrated compellingly in children under the age of 10 years, in contrast with the array of other multisensory skills that children show even in infancy. Instead, across a wide variety of studies, precision with both cues is no better than the best single cue - and sometimes worse. Here we provide the first consistent evidence of cue combination in children from 7 to 10 years old. Across three experiments, participants showed evidence of a bimodal precision advantage (Experiments 1a and 1b) and the majority were best-fit by a combining model (Experiment 2). The task was to localize a target horizontally with a binaural audio cue and a noisy visual cue in immersive virtual reality. Feedback was given as well, which could both (a) help participants judge how reliable each cue is and (b) help correct between-cue biases that might prevent cue combination. Crucially, our results show cue combination when feedback is only given on single cues - therefore, combination itself was not a strategy learned via feedback. We suggest that children at 7-10 years old are capable of cue combination in principle, but must have sufficient representations of reliabilities and biases in their own perceptual estimates as relevant to the task, which can be facilitated through task-specific feedback.