Biology subjects

Negen, J.

Publications and source records attributed to Negen, J..

5 recordsLinked to original sources

bioRxiv2021

Central tendency biases must be accounted for to consistently capture Bayesian cue combination in continuous response data

Observers in perceptual tasks are often reported to combine multiple sensory cues in a weighted average that improves precision - in some studies, approaching statistically-optimal (Bayesian) weighting, but in others departing from optimality, or not benefitting from combined cues at all. To correctly conclude which combination rules observers use, it is crucial to have accurate measures of their sensory precision and cue weighting. Here, we present a new approach for accurately recovering these parameters in perceptual tasks with continuous responses. Continuous responses have many advantages, but are susceptible to a central tendency bias, where responses are biased towards the central stimulus value. We show such biases lead to inaccuracies in estimating both precision gains and cue weightings, two key measures used to assess sensory cue combination. We introduce a method that estimates sensory precision by regressing continuous responses on targets and dividing the variance of the residuals by the squared slope of the regression line, "correcting-out" the error introduced by the central bias and increasing statistical power. We also suggest a complementary analysis that recovers the sensory cue weights. Using both simulations and empirical data, we show that the proposed methods can accurately estimate sensory precision and cue weightings in the presence of central tendency biases. We conclude that central tendency biases should be (and can easily be) accounted for to consistently capture Bayesian cue combination in continuous response data.

neuroscience↗

bioRxiv2019

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. Debates over how this happens have been extensive. A new theory, Adaptive Combination, suggests that the information from different spatial cues are combined with Bayesian efficiency. To test this further, we modified the standard reorientation paradigm to be more amenable to Bayesian cue combination analyses while still requiring reorientation, still requiring participants to recall goal locations from memory, and focusing on situations that require the use of the allocentric (world-based; not egocentric) frame. 12 adults and 20 children at 5-7 years old were asked to recall locations in a virtual environment after a disorientation. They could use either a pair of landmarks at the North and South, a pair at the East and West, or both. 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 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 - regardless of whether the use of the allocentric frame is forced by disorientation or another method. These failures to benefit from a Bayesian strategy accord with the broad idea that there are important limits to Bayesian theories of the cognition, particularly for complex tasks such as allocentric recall.

neuroscience↗

bioRxiv2018

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 7-10 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. A feedback effect was found in Experiment 2, with children who were given single-cue feedback showing the highest rate of cue combination. Given this, 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.

neuroscience↗

bioRxiv2018

Boundaries in Spatial Cognition: How They Look is More Important than What They Do

Large walls and other typical boundaries strongly influence neural activity related to navigation and the representations of spatial layouts. They are also major aids to reliable navigation behavior in young children and non-human animals. Is this because they are physical boundaries (barriers to movement), or because they present certain visual features, such as visually extended 3D surfaces? Here, these two factors were dissociated by using immersive virtual reality and real boundaries. Eighty adults recalled target locations in one of four environments: plywood, where a virtual wall coincided with a large piece of real plywood; pass through, where the virtual wall coincided with empty space and participants could pass through it; pass over, where the virtual wall was projected downward to be visible underneath a transparent floor; and cones, where the walls were replaced with traffic cones. One condition had features that were boundaries and looked like boundaries (plywood); two had features that were not boundaries but looked like boundaries (pass over/through); and one had features that were not boundaries and did not look like boundaries (cones). The precision and bias of responses changed only as a function of looking like a boundary. This suggests that variations in spatial coding are more closely linked to the visual properties of environmental layouts than to whether they contain physical boundaries (barriers to movement).

animal behavior and cognition↗

bioRxiv2017

Integration of A New Sensory Skill with Vision After Less Than 3 Hours of Training

Humans are effective at dealing with noisy, probabilistic information in familiar settings. One hallmark of this is Bayesian Cue Combination: combining multiple noisy estimates to increase precision beyond the best single estimate, taking into account their reliabilities. Here we show that adults also combine a novel audio cue to distance, akin to human echolocation, with a visual cue. Following two hours of training, subjects were more precise given both cues together versus the best single cue. This persisted when we changed the novel cues auditory frequency. Reliability changes also led to a re-weighting of cues without feedback, showing that they learned something more flexible than a rote decision rule for specific stimuli. The main findings replicated with a vibrotactile cue. These results show that the mature sensory apparatus can learn to flexibly integrate new sensory skills. The findings are unexpected considering previous empirical results and current models of multisensory learning.

animal behavior and cognition↗