Avoiding Alzheimer's? - Schizophrenia & Blindness - Offsetting Bias - Friend to Foe

[Breedlove, S]

https://www.nature.com/articles/d41586-026-02098-z

How to avoid dementia — what the science really says

    Helen Pearson 

Sometimes, Kristine Yaffe will hear a poignant question from someone at her memory clinic. “I walk five miles a day, don’t drink and play bridge,” they’ll say, “so why do I have Alzheimer’s disease?

Yaffe, a neurologist and dementia specialist at the University of California, San Francisco, finds it difficult to explain that even if someone does everything they can to lower the risk of dementia, there’s no guarantee they’ll avoid the condition.

Her struggles mirror a challenge in her field. Studies have identified a list of virtuous lifestyle choices associated with a reduced dementia risk, including a healthy diet, physical exercise and social and cognitive stimulation. Research has also pointed to some less obvious factors linked to lower risk, such as treating vision and hearing loss and, potentially, receiving a shingles vaccine. The trouble is that it’s hard to work out how much doing any — or all — of these things helps to reduce risk in the real world.

That’s not for lack of trying. A growing number of ambitious clinical trials have tested the effects of lifestyle interventions, providing people with intensive help to improve their diet, exercise regime, social connections and heart and brain health. These include the FINGER trial1, which involved some 2,650 participants testing a two-year lifestyle overhaul in Finland, and the multimillion-dollar POINTER study2, which tested a similar approach in the United States. These and other studies have suggested that lifestyle programmes can boost cognitive performance.

But these intensive interventions seem to help only slightly — a benefit equivalent to a modest boost on some memory tests. None has been shown to reduce the incidence of dementia, and critics argue that such programmes are costly and difficult to scale up.

Other trials, including offshoots of the FINGER study in the Netherlands and in 12 Latin American countries, will announce their results this month, and the World Health Organization will release its new dementia risk-reduction guidelines on 16 July. Deciphering the most effective ways to cut risks is important for researchers, clinicians and the public alike — especially given that the number of people with dementia worldwide is expected to soar in decades to come.
© 2026 Springer Nature Limited

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https://www.discovermagazine.com/the-mystery-of-why-there-hasn-t-been-a-confirmed-case-of-schizophrenia-in-people-born-blind-49361

Mystery of Why There Hasn't Been a Confirmed Case of Schizophrenia in People Born Blind

 by Avery Hurt

In 1950, researchers Hector Chevigny and Sydell Braverman set out to, as they put it, “demolish old fables about the emotional life of the blind” and demonstrate that the mental health issues of the blind are no different from those experienced by the sighted.

But they did discover one big — and very surprising — difference: There have been no reported cases of schizophrenia in people blind from birth (or who became blind very shortly after birth). At the time, there was limited patient data available, so it wasn’t clear if this astonishing finding would hold up. But in the almost 80 years since, more national databases of mental illness have been maintained, and still no cases have been found, according to a study in Frontiers in Psychology.

Is it just a coincidence? Or does never having been able to see somehow offer protection from schizophrenia? And if it does, how would that even work?

Schizophrenia is a neurodevelopmental disorder that interferes with the way people interpret reality, Philip Corlett, a neuroscientist at Yale University who studies psychosis and delusional thinking, told Discover. Schizophrenia can cause symptoms such as hallucinations, disorganized speech and thinking, and in some cases, a lack of motivation or engagement with the world.

However, the most familiar characteristic of the illness is what Corlett described as “departures from consensus reality,” or, put another way, believing things that most people in your culture don’t believe.

Though the causes and mechanisms of schizophrenia are not yet well understood, one increasingly accepted theory is that the illness results from errors in prediction. To understand that, we need to take a look at how the healthy brain processes information.

© 2026 Discover Magazine Inc
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https://aeon.co/essays/can-mindfulness-help-you-overcome-your-cognitive-biases

How to offset your brain

Stephanie Dorais

You slide your hand into your coat pocket and find an old, folded $100 bill. In the other pocket, you find a coin.

Now, here’s the gamble: flip the coin. Heads, you win another $300. Tails, you hand over your $100 bill. Do you take the risk?

Mathematically, you should. One coin flip gives you two equally likely futures: in one, heads, you gain $300; in the other, tails, you lose $100.

Because each future has a 50 per cent chance of happening, you count half of each outcome: half of $300 is $150, and half of $100 is $50. Balance those against each other, and taking the gamble puts you $100 ahead on average. Decision scientists call this positive expected value.

Even when someone grasps the mathematics, however, it’s hard to take the risk. Why?

About 50 years ago, the psychologists Amos Tversky and Daniel Kahneman showed that this hesitation is not random. People depart from logic in patterned ways. One of the most durable patterns is loss aversion: our tendency to feel the pain of losing more sharply than the pleasure of an equivalent, or even greater, gain.

This is where mindfulness becomes interesting. Mindfulness is usually defined as paying attention to the present moment, on purpose, without immediately judging what is happening. In practice, that can mean noticing a thought before believing it, feeling an emotion before acting on it, or returning attention to the body, the breath, or the world around you. At its simplest, mindfulness creates a pause between what arises in the mind and what we do next.

That pause helps because many of our choices are made before we have fully examined them. We may think we are deliberating over the coin toss, but often the body has moved first: recoiling from loss or preserving a decision simply because we have already invested in it. These mental shortcuts are called cognitive biases, and the study of this kind of human misjudgment is central to decision science.

© Aeon Media Group Ltd. 2012-2026. 
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https://www.thetransmitter.org/social-behavior/from-friend-to-foe-how-the-brain-updates-feelings-toward-others/

 From friend to foe: How the brain updates feelings toward others

By Natalia Mesa

If a longtime friend suddenly becomes a foe, like Brutus to Caesar or Iago to Othello, the brain must update the person’s feelings about the betrayer without altering memories of who that companion is. 

The hippocampus may sometimes store both pieces of information, but when it comes to updating feelings, it keeps identity and emotional valence separate, according to a mouse study published today in Science.

“We found the neural mechanisms that underlie emotion toward others,” says study investigator Teruhiro Okuyama, professor at the Institute of Quantitative Biosciences at the University of Tokyo: Memory-storing neurons in the hippocampus remain relatively stable, but the strength of their connections to the basolateral amygdala neurons shift, the study shows. 

Okuyama and his colleagues used chemogenetics to induce aggression in previously docile mice and optogenetics to trace how hippocampal circuits change in the animal’s cagemate. They found that they could both “write and erase social memories” by targeting specific neuron populations. 

“It’s truly unbelievable how much they did in this paper,” says Robert Malenka, professor of psychiatry and behavioral sciences at Stanford University, who was not involved in the work. “They did a beautiful job of taking three brain areas and defining the connectivity and the cell-type-specific connections that are responsible for the phenomenon they’re studying.”

Neurons in the hippocampus store social memories and segregate positive and negative ones, previous work shows. But most past work has studied how negative run-ins with unfamiliar animals affect behavior. 

© 2026 Simons Foundation

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https://nautil.us/how-the-rule-breaking-octopus-is-rewriting-the-evolution-of-intelligence-1282633

How the Rule-Breaking Octopus Is Rewriting the Evolution of Intelligence

By Jake Currie

One theory, the social brain hypothesis, says we owe our massive noggins in part to the evolutionary pressure exerted by the demands of large social groups. Because we needed to keep a running tally of friends and foes to navigate thorny hierarchies and shifting alliances, we had to have brains that were up to the task (which is why this theory is also known as the Machiavellian intelligence hypothesis). 

In many animals, especially mammals, there does seem to be a correlation between social group size and brain size. But there’s at least one big exception to this rule: cephalopods. 

Cephalopods like octopuses have huge brains but aren’t really known for their gregarious behavior. They tend to live solitary lives, mating without forming pair bonds and reproducing without parenting their young. In fact, their behavior can stray into the downright anti-social—many species are territorial, aggressive, and cannibalistic. Still, they’re incredibly intelligent. Octopuses use tools, solve problems, and even like to play.

So if sociality can’t explain big cephalopod brains, what can? 

In a new paper published in iScience, an international team of researchers proposed a new version of the cultural brain hypothesis. This hypothesis—first advanced by one of the authors of the current study—states that big brains evolved to handle mountains of information that are learned both socially and asocially. In this latest research, the team focuses solely on the asocial pathway to brain evolution. 

To test their asocial brain hypothesis, the team compiled data on cephalopod brain size as well as ecological, behavioral, and social factors from 79 cephalopod species. They found that several ecological factors seemed to correlate with big cephalopod brains, especially the complexity of their habitats. Cephalopods that lived on the ocean floor and in shallow pools—where cleverness can be rewarded with calorie-rich prey—tended to have larger brains. Sociality, on the other hand, showed no such correlation. 
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