Natural statistics support a rational account of confidence biases.

Previous work has sought to understand decision confidence as a prediction of the probability that a decision will be correct, leading to debate over whether these predictions are optimal, and whether they rely on the same decision variable as decisions themselves. This work has generally relied on idealized, low-dimensional models, necessitating strong assumptions about the representations over which confidence is computed. To address this, we used deep neural networks to develop a model of decision confidence that operates directly over high-dimensional, naturalistic stimuli. The model accounts for a number of puzzling dissociations between decisions and confidence, reveals a rational explanation of these dissociations in terms of optimization for the statistics of sensory inputs, and makes the surprising prediction that, despite these dissociations, decisions and confidence depend on a common decision variable.

Blockchain for Electronic Vaccine Certificates: More Cons Than Pros?

Electronic vaccine certificates (EVC) for COVID-19 vaccination are likely to become widespread. Blockchain (BC) is an electronic immutable distributed ledger and is one of the more common proposed EVC platform options. However, the principles of blockchain are not widely understood by public health and medical professionals. We attempt to describe, in an accessible style, how BC works and the potential benefits and drawbacks in its use for EVCs. Our assessment is BC technology is not well suited to be used for EVCs. Overall, blockchain technology is based on two key principles: the use of cryptography, and a distributed immutable ledger in the format of blockchains. While the use of cryptography can provide ease of sharing vaccination records while maintaining privacy, EVCs require some amount of contribution from a centralized authority to confirm vaccine status; this is partly because these authorities are responsible for the distribution and often the administration of the vaccine. Having the data distributed makes the role of a centralized authority less effective. We concluded there are alternative ways to use cryptography outside of a BC that allow a centralized authority to better participate, which seems necessary for an EVC platform to be of practical use.

Elective Deliveries and the Risk of Autism.

INTRODUCTION: Cesarean section and induced deliveries have increased substantially in the U.S., coinciding with increases in autism spectrum disorder. Studies have documented associations between cesarean section deliveries and autism spectrum disorder but have not comprehensively accounted for medical risks. This study evaluates the extent to which cesarean section and induced deliveries are associated with autism spectrum disorder in low-risk births. METHODS: In this retrospective cohort study, California's birth records (1992-2012) were linked to hospital discharge records to identify low-risk births using a stringent algorithm based on Joint Commission guidelines. Autism spectrum disorder status was based on California Department of Developmental Service data. Logistic regression models were used to estimate associations between autism spectrum disorder and induced vaginal deliveries, cesarean section deliveries not following induction, and cesarean section deliveries following induction, with noninduced vaginal deliveries as the reference category. RESULTS: A total of 1,488,425 low-risk births took place in California from 1992 to 2012. The adjusted odds of autism spectrum disorder were 7% higher for induced vaginal deliveries (AOR=1.07, 95% CI=1.01, 1.14), 26% higher for cesarean section deliveries not following induction (AOR=1.26, 95% CI=1.19, 1.33), and 31% higher for cesarean section deliveries following induction (AOR=1.31, 95% CI=1.18, 1.45) than for noninduced vaginal deliveries. Lower gestational age and neonatal morbidities did not appear to be important underlying pathways. The associations were insensitive to alternative model specifications and across subpopulations. These results suggest that, in low-risk pregnancies, up to 10% of autism spectrum disorder cases are potentially preventable by avoiding cesarean section deliveries. CONCLUSIONS: After accounting for medical risks, elective deliveries-particularly cesarean section deliveries-were associated with a substantially increased risk of autism spectrum disorder.

Normal observers show no evidence for blindsight in facial emotion perception.

Some researchers have argued that normal human observers can exhibit "blindsight-like" behavior: the ability to discriminate or identify a stimulus without being aware of it. However, we recently used a bias-free task to show that what looks like blindsight may in fact be an artifact of typical experimental paradigms' susceptibility to response bias. While those findings challenge previous reports of blindsight in normal observers, they do not rule out the possibility that different stimuli or techniques could still reveal perception without awareness. One intriguing candidate is emotion processing, since processing of emotional stimuli (e.g. fearful/happy faces) has been reported to potentially bypass conscious visual circuits. Here we used the bias-free blindsight paradigm to investigate whether emotion processing might reveal "featural blindsight," i.e. ability to identify a face's emotion without introspective access to the task-relevant features that led to the discrimination decision. However, we saw no evidence for emotion processing "featural blindsight": as before, whenever participants could identify a face's emotion they displayed introspective access to the task-relevant features, matching predictions of a Bayesian ideal observer. These results add to the growing body of evidence that perceptual discrimination ability without introspective access may not be possible for neurologically intact observers.

New measures of agency from an adaptive sensorimotor task.

Self-agency, the sense that one is the author or owner of one's behaviors, is impaired in multiple psychological and neurological disorders, including functional movement disorders, Parkinson's Disease, alien hand syndrome, schizophrenia, and dystonia. Existing assessments of self-agency, many of which focus on agency of movement, can be prohibitively time-consuming and often yield ambiguous results. Here, we introduce a short online motion tracking task that quantifies movement agency through both first-order perceptual and second-order metacognitive judgments. The task assesses the degree to which a participant can distinguish between a motion stimulus whose trajectory is influenced by the participant's cursor movements and a motion stimulus whose trajectory is random. We demonstrate the task's reliability in healthy participants and discuss how its efficiency, reliability, and ease of online implementation make it a promising new tool for both diagnosing and understanding disorders of agency.