Submission + - Implication of Bayesian reasoning in some mental disorder cases (sciencenews.org)
Taco Cowboy writes: Bayesian theorem describes the probability of an event, based on conditions that might be related to the event, but in specific mental disorders the slightest 'misses' of Bayesian guesses lead into dangerous conclusions after inner amplifying loops
People have assumptions about the world, which are either inborn or learned early in life. For example:
Light comes from above
Noses stick out
Objects move slowly
Background images are uniformly colored
Other people’s gazes are directed at us
From within the dark confines of the skull, the brain builds its own version of reality. By weaving together expectations and information gleaned from the senses, the brain creates a story about the outside world
Guesses just slightly off — like mistaking a smile for a smirk — rarely cause harm. But guessing gone seriously awry may play a part in mental illnesses such as schizophrenia, autism and even anxiety disorders
Experiments guided by Bayesian math reveal that the guessing process differs in people with some disorders
People with schizophrenia, for instance, can have trouble tying together their expectations with what their senses detect. And people with autism and high anxiety don’t flexibly update their expectations about the world, some lab experiments suggest. That missed step can muddy their decision-making abilities
Given the complexity of mental disorders such as schizophrenia and autism, it is no surprise that many theories of how the brain works have fallen short
Current explanations for the disorders are often vague and untestable. Against that frustrating backdrop, great promises are embedded in a strong mathematical theory, one that can be used to make predictions and may actually be able to test them
Bayesian reasoning may be new to the mental illness scene, but the math itself has been around for centuries. First described by the Rev. Thomas Bayes in the 18th century, this computational approach truly embraces history: Evidence based on previous experience, known as a “prior,” is essential to arriving at a good answer, Bayes argued
He may have been surprised to see his math meticulously applied to people with mental illness, but the logic holds
To make a solid guess about what’s happening in the world, the brain must not rely just on current input from occasionally unreliable senses. The brain must also use its knowledge about what has happened before. Merging these two streams of information correctly is at the heart of perceiving the world as accurately as possible
For example, this image — https://www.sciencenews.org/si... — for ordinary people hollow face on the right looks 'protruding', but the same hollow face won't fool those who are infected with schizophrenia
The way the brain combines incoming sensory information with existing knowledge may also be different in autism, some researchers argue. In some cases, people with autism might put excess weight on what their senses take in about the world and rely less on their expectations
Distorted calculations — and the altered versions of the world they create — may also play a role in depression and anxiety, some researchers think. While suffering from depression, people may hold on to distorted priors — believing that good things are out of reach, for instance. And people with high anxiety can have trouble making good choices in a volatile environment, neuroscientist Sonia Bishop of the University of California, Berkeley and colleagues reported in 2015 in Nature Neuroscience
Scientists can’t yet say what causes this difficulty adjusting to a new environment in anxious people and in people with autism. It could be that once some rule is learned (a sequence of computer keys, or the link between a shape and a shock), these two groups struggle to update that prior with newer information
Math may be able to help clarify mental illnesses in a way that existing approaches can’t, by demystifying psychiatric disorders
By treating the brain as a Bayesian number cruncher, it might lead to a more rigorous understanding of mental illness
Scientists hope that a deeper description of mental illnesses may lead to clearer ways to identify a disorder, chart how well treatments work and even improve therapies. Cognitive behavioral therapy could help depressed people recalculate their experiences by putting less weight on negative experiences and perhaps breaking out of cycles of despondence
Beyond these potential interventions, simply explaining to people how their brains are working might ease distress
“If you can give people an explanation that makes sense of some of the experiences they’ve had, that can be a profoundly helpful thing. It destigmatizes the experience”
People have assumptions about the world, which are either inborn or learned early in life. For example:
Light comes from above
Noses stick out
Objects move slowly
Background images are uniformly colored
Other people’s gazes are directed at us
From within the dark confines of the skull, the brain builds its own version of reality. By weaving together expectations and information gleaned from the senses, the brain creates a story about the outside world
Guesses just slightly off — like mistaking a smile for a smirk — rarely cause harm. But guessing gone seriously awry may play a part in mental illnesses such as schizophrenia, autism and even anxiety disorders
Experiments guided by Bayesian math reveal that the guessing process differs in people with some disorders
People with schizophrenia, for instance, can have trouble tying together their expectations with what their senses detect. And people with autism and high anxiety don’t flexibly update their expectations about the world, some lab experiments suggest. That missed step can muddy their decision-making abilities
Given the complexity of mental disorders such as schizophrenia and autism, it is no surprise that many theories of how the brain works have fallen short
Current explanations for the disorders are often vague and untestable. Against that frustrating backdrop, great promises are embedded in a strong mathematical theory, one that can be used to make predictions and may actually be able to test them
Bayesian reasoning may be new to the mental illness scene, but the math itself has been around for centuries. First described by the Rev. Thomas Bayes in the 18th century, this computational approach truly embraces history: Evidence based on previous experience, known as a “prior,” is essential to arriving at a good answer, Bayes argued
He may have been surprised to see his math meticulously applied to people with mental illness, but the logic holds
To make a solid guess about what’s happening in the world, the brain must not rely just on current input from occasionally unreliable senses. The brain must also use its knowledge about what has happened before. Merging these two streams of information correctly is at the heart of perceiving the world as accurately as possible
For example, this image — https://www.sciencenews.org/si... — for ordinary people hollow face on the right looks 'protruding', but the same hollow face won't fool those who are infected with schizophrenia
The way the brain combines incoming sensory information with existing knowledge may also be different in autism, some researchers argue. In some cases, people with autism might put excess weight on what their senses take in about the world and rely less on their expectations
Distorted calculations — and the altered versions of the world they create — may also play a role in depression and anxiety, some researchers think. While suffering from depression, people may hold on to distorted priors — believing that good things are out of reach, for instance. And people with high anxiety can have trouble making good choices in a volatile environment, neuroscientist Sonia Bishop of the University of California, Berkeley and colleagues reported in 2015 in Nature Neuroscience
Scientists can’t yet say what causes this difficulty adjusting to a new environment in anxious people and in people with autism. It could be that once some rule is learned (a sequence of computer keys, or the link between a shape and a shock), these two groups struggle to update that prior with newer information
Math may be able to help clarify mental illnesses in a way that existing approaches can’t, by demystifying psychiatric disorders
By treating the brain as a Bayesian number cruncher, it might lead to a more rigorous understanding of mental illness
Scientists hope that a deeper description of mental illnesses may lead to clearer ways to identify a disorder, chart how well treatments work and even improve therapies. Cognitive behavioral therapy could help depressed people recalculate their experiences by putting less weight on negative experiences and perhaps breaking out of cycles of despondence
Beyond these potential interventions, simply explaining to people how their brains are working might ease distress
“If you can give people an explanation that makes sense of some of the experiences they’ve had, that can be a profoundly helpful thing. It destigmatizes the experience”
