Imagine you're at a magic show, in which the performer suddenly vanishes. Of course, you ultimately know that the person is probably just hiding somewhere. Yet it continues to look as if the person has disappeared. We can't reason away that appearance, no matter what logic dictates. Why are our conscious experiences so stubborn?

The fact that our perception of the world appears to be so intransigent, however much we might reflect on it, tells us something unique about how our brains are wired. Compare the magician scenario with how we usually process information. Say you have five friends who tell you it's raining outside, and one weather website indicating that it isn't. You'd probably just consider the website to be wrong and write it off. But when it comes to conscious perception, there seems to be something strangely persistent about what we see, hear and feel. Even when a perceptual experience is clearly 'wrong', we can't just mute it.

Why is that so? Recent advances in artificial intelligence (AI) shed new light on this puzzle. In computer science, we know that neural networks for pattern-recognition - so-called deep learning models - can benefit from a process known as predictive coding. Instead of just taking in information passively, from the bottom up, networks can make top-down hypotheses about the world, to be tested against observations. They generally work better this way. When a neural network identifies a cat, for example, it first develops a model that allows it to predict or imagine what a cat looks like. It can then examine any incoming data that arrives to see whether or not it fits that expectation.

In 2015, doctors in Germany reported the extraordinary case of a woman who suffered from what has traditionally been called "multiple personality disorder" and today is known as "dissociative identity disorder" (DID). The woman exhibited a variety of dissociated personalities ("alters"), some of which claimed to be blind. Using EEGs, the doctors were able to ascertain that the brain activity normally associated with sight wasn't present while a blind alter was in control of the woman's body, even though her eyes were open. Remarkably, when a sighted alter assumed control, the usual brain activity returned.

This was a compelling demonstration of the literally blinding power of extreme forms of dissociation, a condition in which the psyche gives rise to multiple, operationally separate centers of consciousness, each with its own private inner life.

Modern neuroimaging techniques have demonstrated that DID is real: in a 2014 study, doctors performed functional brain scans on both DID patients and actors simulating DID. The scans of the actual patients displayed clear differences when compared to those of the actors, showing that dissociation has an identifiable neural activity fingerprint. In other words, there is something rather particular that dissociative processes look like in the brain.

There is also compelling clinical data showing that different alters can be concurrently conscious and see themselves as distinct identities. One of us has written an extensive treatment of evidence for this distinctness of identity and the complex forms of interactive memory that accompany it, particularly in those extreme cases of DID that are usually referred to as multiple personality disorder.

A long-awaited resurgence in psychedelic research is now under way and some of its early results have been startling. Whereas most scientists expected the mind-boggling experiences of psychedelic states to correlate with increased brain activity, a landmark study from 2012 found the opposite to be the case. Writing in this magazine, neuroscientist Christof Koch expressed the community's collective surprise. These unexpected findings have since been repeatedly confirmed with a variety of psychedelic agents and measures of brain activity (2013, 2015, 2016, 2017).

Under the mainstream physicalist view that brain activity is, or somehow generates, the mind, the findings certainly seem counterintuitive: How can the richness of experience go up when brain activity goes down? Understandably, therefore, researchers have subsequently endeavored to find something in patterns of brain activity that reliably increases in psychedelic states. Alternatives include brain activity variability, functional coupling between different brain areas and, most recently, a property of brain activity variously labeled as "complexity," "diversity," "entropy" or "randomness" - terms viewed as approximately synonymous.

The problem is that modern brain imaging techniques do detect clear spikes in raw brain activity when sleeping subjects dream even of dull things such as staring at a statue or clenching a hand. So why are only decreases in brain activity conclusively seen when subjects undergo psychedelic experiences, instead of dreams? Given how difficult it is to find one biological basis for consciousness, how plausible is it that two fundamentally different mechanisms underlie conscious experience in the otherwise analogous psychedelic and dreaming states?

Every day, millions of people turn to acetaminophen, also known as paracetamol - the active ingredient in Tylenol - to dull the occasional ache or pain. That's because few side effects accompany this highly effective over-the-counter drug when taken at recommended doses. A new side effect is starting to come to light, however. Research is now revealing that acetaminophen may subtly influence your emotions.

To relieve pain, acetaminophen works its magic in the brain, but researchers still aren't entirely sure how this trick works - a remarkable fact considering the drug has been available without prescription for sixty years! It may impact an enzyme called cyclooxygenase, or it might modulate humans' endocannabinoid system. Some experts say one or both of these ideas tells the whole story, while others insist we've barely scratched the surface. Regardless, whatever acetaminophen does in the brain also seems to alter how we perceive the world.

One of the earliest and most elucidating studies on the topic was published back in 2010. A team of scientists from a variety of academic institutions in the U.S. found that subjects who took acetaminophen were not as sensitive to emotional pain compared to people given a placebo.

"In two experiments, participants took acetaminophen or placebo daily for 3 weeks," they described. "Doses of acetaminophen reduced reports of social pain on a daily basis."

The team also found a "smoking gun" of sorts when conducting brain scans on the participants.

"I am convinced the devil lives in our phones."

The people who are closest to a thing are often the most wary of it. Technologists know how phones really work, and many have decided they don't want their own children anywhere near them.

A wariness that has been slowly brewing is turning into a region wide consensus: The benefits of screens as a learning tool are overblown, and the risks for addiction and stunting development seem high. The debate in Silicon Valley now is about how much exposure to phones is O.K.

"Doing no screen time is almost easier than doing a little," said Kristin Stecher, a former social computing researcher married to a Facebook engineer. "If my kids do get it at all, they just want it more."

Ms. Stecher, 37, and her husband, Rushabh Doshi, researched screen time and came to a simple conclusion: they wanted almost none of it in their house. Their daughters, ages 5 and 3, have no screen time "budget," no regular hours they are allowed to be on screens. The only time a screen can be used is during the travel portion of a long car ride (the four-hour drive to Tahoe counts) or during a plane trip.

On this first episode of MindMatters, we dive into the biggest mystery of our times: consciousness. What is it, why is it so mysterious, and why is it important? Materialists either explain it away or deny it really exists, but the mind is much more than that. It can't be so easily denied. Everything in our experience, from our sensations and feelings to our theories and choices in life - all of these depend on our minds.

Summing up many of the topics we have looked at on our previous show, the Truth Perspective, today we put together ideas from Andrew Lobaczewski, James C. Carpenter, Whitehead and Griffin, and Jordan B. Peterson. We also examine a clip from Peterson's latest Q&A on how our aims structure everything in our experience from our perception to the choices we make in life.

If you like what you see, make sure to subscribe to our new YouTube channel, MindMatters.


Running Time: 01:34:39

Download: MP3 - 86.7 MB

One of the thorniest debates in neuroscience is whether people can make new neurons after their brains stop developing in adolescence - a process known as neurogenesis. Now, a new study finds that even people long past middle age can make fresh brain cells, and that past studies that failed to spot these newcomers may have used flawed methods.

The work "provides clear, definitive evidence that neurogenesis persists throughout life," says Paul Frankland, a neuroscientist at the Hospital for Sick Children in Toronto, Canada. "For me, this puts the issue to bed."

Researchers have long hoped that neurogenesis could help treat brain disorders like depression and Alzheimer's disease. But last year, a study in Nature reported that the process peters out by adolescence, contradicting previous work that had found newborn neurons in older people using a variety of methods. The finding was deflating for neuroscientists like Frankland, who studies adult neurogenesis in the rodent hippocampus, a brain region involved in learning and memory. It "raised questions about the relevance of our work," he says.

Once the exclusive preserve of philosophy and theology, the study of morality has now become a thriving interdisciplinary endeavor, encompassing research in evolutionary theory, genetics, biology, animal behavior, psychology, and anthropology. The emerging consensus is that there is nothing mysterious about morality; it is merely a collection of biological and cultural traits that promote cooperation.

Best known among these accounts is Jonathan Haidt's Moral Foundations Theory (MFT). According to MFT: "Moral systems are interlocking sets of values, virtues, norms, practices, identities, institutions, technologies, and evolved psychological mechanisms that work together to suppress or regulate selfishness and make cooperative social life possible." And MFT proceeds to argue that, because humans face multiple social problems, they have multiple moral values-they rely on multiple "foundations" when making moral decisions. These foundations include: Care, Fairness, Loyalty, Authority, and Purity.

• Care: "The suffering of others, including virtues of caring and compassion."
• Fairness: "Unfair treatment, cheating, and more abstract notions of justice and rights."
• Loyalty: The "obligations of group membership" including "self-sacrifice, and vigilance against betrayal."
• Authority: "Social order and the obligations of hierarchical relationships, such as obedience, respect, and the fulfillment of role-based duties."
• Purity: "Physical and spiritual contagion, including virtues of chastity, wholesomeness, and control of desires."

These moral foundations have been operationalized, and measured, by the Moral Foundations Questionnaire (MFQ; you can complete it here).

The illusion of truth is a mechanism by which one comes to believe something is true when it's not. In fact, they don't just believe it; they also defend it as true. Also, they close themselves off to the possibility that it might be false.

The illusion of truth, also called the illusory truth effect, occurs because there's a flaw in the processing of reality. As humans, we have the tendency to say that familiar things are true.

In 1977, a study was done on it. A group of volunteers was presented with 60 statements. Researchers asked them to say if they were true or false. The same exercise was repeated later. The researchers noticed that these people deemed the statements they had already read before as true, regardless of how reasonable they were.

"A lie would have no sense unless the truth were felt dangerous."
-Alfred Adler-

Psychologists have devoted much time over the last two decades documenting the dark side of human nature as encapsulated by the so-called Dark Triad of traits: psychopathy, Machiavellianism, and narcissism. People who score highly in these traits, who break the normal social rules around modesty, fairness and consideration for others, seem to fascinate as much as they appall. But what about those individuals who are at the other extreme, who through their compassion and selflessness are exemplars of the best of human nature? There is no catchy name for their personality traits, and while researchers have studied altruism, forgiveness, gratitude and other jewels in our behavioural repertoire, the light side of human personality has arguably not benefited from the same level of attention consumed by the dark side.

Writing in the journal Frontiers in Psychology, a team led by US psychologist and author Scott Barry Kaufman at Barnard College, Columbia University says it is high time we redressed this imbalance. "Too much focus on one aspect of human nature at the expense of the other misrepresents the full capacities of humanity," they write. Through four studies featuring more than 1,500 online participants, Kaufman and his team have created a new questionnaire that taps what they are calling the Light Triad (see example items below, and you can take the test online). They've also provided preliminary evidence for the kind of personal characteristics and psychological outcomes that are associated with being a high scorer on the light side of personality - or what they call an "everyday saint".

The research involved participants rating their agreement with statements designed to tap into the more positive, compassionate and selfless aspects of human personality. Kaufman's team took inspiration for these items from surveys used to measure the Dark Triad, but they made sure that their new items were not simply the Dark Triad questionnaire items in reverse; they also sought advice from experts in positive psychology and personality psychology to help them with the compilation. Participants also completed established measures of the Dark Triad, of the Big Five personality traits, and various other measures of psychological outcomes, well-being, values and characteristics.