The Psych Files

Author: Michael Britt

  • Your Muscles Are Talking to Your Brain — and It Might Be Why Exercise Fights Depression

    Your Muscles Are Talking to Your Brain — and It Might Be Why Exercise Fights Depression

    You already know what people tell you when you say you’re feeling low: go for a walk, get some exercise, you’ll feel better. And maybe part of you bristles at that, because it sounds too simple to be real. How is moving your legs supposed to touch something as heavy as depression? Well, scientists have just traced the actual messenger that carries the news from your muscles up to your brain — and it turns out the advice has a real chemical backbone.

    The study appeared in Molecular Psychiatry and was led by Suk-Yu Yau, an associate professor in the Department of Rehabilitation Sciences at Hong Kong Polytechnic University, working with a team across several institutions. They zeroed in on a protein called apelin. When you work your muscles, they don’t just burn calories — they release proteins into the bloodstream that act like messengers to the rest of the body. Apelin is one of those messengers, and your muscles pump out more of it when you push them.

    Here’s what the team did. They took mice and put them through a few weeks of mild, unpredictable stress until the animals showed the rodent version of major depressive disorder — the persistent low mood and loss of interest in pleasure that defines the condition in people. The stressed mice stopped preferring sugar water, groomed themselves less, and gave up faster in a swim test. Then some of them got a running wheel. After four weeks of voluntary running, the exercising mice bounced back on all three measures, and their blood and brains were noticeably richer in apelin. The biggest source? The calf and shin muscles of the hind legs.

    Then came the clever part. The researchers bred mice whose muscles couldn’t make apelin at all. Those mice ran just as much — and got nothing for it. No mood improvement, and no growth of new brain cells. Flip it around: when they used a virus to force ordinary muscles to crank out apelin without any running, those couch-potato mice improved just like the runners did. That’s about as close as biology gets to saying “this one molecule is doing the work.”

    So how does a muscle protein lift your mood? The apelin crossed the blood-brain barrier and reached the hippocampus — a structure deep in the brain that’s central to memory and mood regulation. Once there, it triggered neurogenesis, the birth of brand-new neurons, which the depressed non-runners never got. It also strengthened the connections between existing neurons by boosting their glutamate signaling, the kind of synaptic strengthening researchers call long-term potentiation — the same cellular process behind learning and memory. In other words, exercise wasn’t just making the mice feel better in some vague way. It was physically rebuilding the brain’s wiring, a clear demonstration of plasticity, the brain’s lifelong ability to reshape itself in response to what the body is doing.

    I spent years as a college professor telling students that exercise helps with mood, and honestly, I always felt a little hand-wavy saying it — like I was repeating folk wisdom. Reading this, I finally have the mechanism I wished I’d had back then. It’s a small thing, but it’s satisfying to see a piece of everyday advice turn out to have real machinery underneath it.

    What can you do with this? The finding points to something specific: leg-driven movement seems to matter, since the hind-leg muscles were the main apelin factories. Walking, cycling, stair climbing, squats — the stuff that loads your lower body — looks especially worth keeping in your week. And the researchers stress that holding onto muscle strength as you age may help protect your mood, not just your mobility. You don’t have to run a marathon. You just have to keep your muscles in the conversation.

    One honest caveat: this was done in male mice. The authors are upfront that female, older, and human studies still need to happen before anyone promises results, partly because hormones and muscle mass differ by sex and could change how much apelin the body makes.

    If you’re studying psychology, scroll down — I’ve pulled out the key concepts this research illustrates, with a plain-language definition and a note on how the study demonstrates each one.

    Psychology Terms in This Article

    Major depressive disorder — A mood disorder marked by persistent sadness, hopelessness, and a loss of interest in activities that used to feel rewarding. The researchers induced a rodent model of it through chronic mild stress, then measured it through reduced interest in sugar water (a stand-in for the loss of pleasure called anhedonia) and faster giving-up in a swim test.

    Hippocampus — A structure in the brain’s limbic system that’s essential for forming new memories and helps regulate mood. In this study, the muscle-made apelin traveled all the way to the hippocampus, and that’s where it produced its antidepressant effects — a reminder that this region isn’t just about memory.

    Neurogenesis — The formation of brand-new neurons, which we now know continues in certain brain regions throughout adult life. Exercising mice grew new hippocampal neurons while the non-exercising depressed mice did not, and mice without muscle apelin showed no new growth even when they ran.

    Long-term potentiation (LTP) — A lasting strengthening of the connection between neurons based on recent activity, considered a core cellular mechanism of learning and memory. Apelin enhanced glutamate signaling and the function of NMDA receptors in the hippocampus, strengthening neural connections in exactly the way LTP describes.

    Plasticity — The brain’s capacity to change and reorganize itself in response to experience throughout life. This whole study is a case study in plasticity: a behavior (exercise) sent a chemical signal that physically remodeled brain tissue and shifted mood.

    References

    Yu, J., Cheng, T., Guo, H., Song, Z., Zhong, Y., Lee, T. H., Li, J., Formolo, D. A., Hussain, A., Le, K., Yao, Y., Abel, R. L., Cheung, W.-H., Lin, K., Xu, A., Cheng, K. K.-Y., & Yau, S.-Y. (2026). How muscle talks to brain: apelin protein mediates exercise-induced antidepressant effects. Molecular Psychiatry. https://doi.org/10.1038/s41380-026-03651-y

  • Does Your Dog or Cat Need Closure? Pet Grief and the Psychology of Loss

    Does Your Dog or Cat Need Closure? Pet Grief and the Psychology of Loss

    We hear the word “closure” everywhere — in true crime shows, in news coverage of trials, and in the well-meaning advice of friends after a loss. But where did this idea come from, and does the research actually support it? In this episode I trace the surprising history of closure, from the Gestalt psychologists of the 1920s, to Arie Kruglanski’s research on the “need for cognitive closure,” to its takeover by talk shows, the victims’ rights movement, and even the funeral industry in the 1990s. Along the way we look at what the science really shows: the craving for answers is real and measurable, and confirming the reality of a death does help people grieve. But sociologist Nancy Berns, family therapist Pauline Boss (who coined the term “ambiguous loss”), and a striking study comparing homicide survivors in death penalty and life-sentence states all point to the same conclusion — grief doesn’t have a finish line, and expecting one may do more harm than good.

    And then there’s my cat. After I brought one of my cats to be euthanized, several people asked whether I’d brought my other cat along “so she could have closure.” That question sent me into the research on animal grief: recent studies show that surviving dogs and cats really do change their behavior after a companion dies — seeking attention, eating less, even searching the house for their missing friend. But the one study that looked directly at whether viewing the body makes a difference found no effect at all. So is pet closure real science, or are we projecting a contested human concept onto our animals? Listen in and decide — and then ask yourself who that goodbye ritual is really for.

    References & Resources for This Episode


  • Why Your Favorite Playlist Eventually Bores You — and the Algorithm Is Part of the Problem

    Why Your Favorite Playlist Eventually Bores You — and the Algorithm Is Part of the Problem

    You know that feeling when Spotify hands you a song you instantly love, you play it into the ground for a week, and then somewhere around day ten you can’t stand to hear it again? That’s not just you being fickle. A new study suggests the very algorithm that found you that perfect song might be the thing quietly draining the fun out of your listening — and out of your movies, your shows, and your reading too.

    The research comes from Samsun Knight, an assistant professor at the University of Toronto’s Rotman School of Management who also happens to be a published novelist. His paper, “Engagement-based curation and the evolution of taste,” appeared in the Journal of Cultural Economics. Knight started wondering about this after his own odd experience with Spotify: he’d fall in love with a recommended song, and then the app would keep shoving that same song at him until he couldn’t bear it. Why, he asked, would a company that badly wants you to stay happy keep making you miserable?

    Here’s the core idea. The more you listen to a certain style of music, the better you get at appreciating it — Knight borrows the economists’ term consumption capital for this. But appreciation follows an upside-down U. A moderate amount of exposure makes you like something more. Too much exposure makes you sick of it. This is really a story about the mere exposure effect — the well-documented tendency to like things more simply because they’ve become familiar — running straight into its own limit. Familiarity builds liking, right up until it tips over into “please, anything but this.”

    Now here’s the problem Knight built a mathematical model to expose. Recommendation algorithms optimize for what keeps you clicking today. They test content over a few weeks or months. But real human taste evolves over ten or twenty years. So Knight ran simulations — a thousand separate trials — pitting different kinds of algorithmic “curators” against a simulated listener whose tastes slowly shifted over time. One curator naively assumed that high engagement just meant high quality. It never realized that its own past recommendations were the reason a song felt familiar and got clicked in the first place.

    What happened? The precise, engagement-hungry algorithm stopped exploring almost entirely. When it showed the listener something unfamiliar and got a lukewarm response, it decided that whole genre was bad and buried it. Its exploration rate dropped to zero. Then it played the safe favorites until the listener was thoroughly bored — a self-fulfilling prophecy of monotony. There’s even a name in the paper for the trap: straddling, where the system overplays a great song until you’re sick of it, while occasionally testing a mediocre one just enough to confirm it’s mediocre, never realizing that simply resting the good song would bring the joy back.

    And the punchline, the part I found genuinely surprising: a worse algorithm did better. When Knight added a little random noise — forcing the system to occasionally toss in something unfamiliar — the simulated listeners discovered new styles, built appreciation for them, and got a break from their overplayed favorites. The slightly imperfect system made people happier in the long run. His sharpest example is hip-hop. It took a lot of listeners years to learn how to hear it; early on it sounded abrasive to ears raised on rock and roll. Knight points out that if a 1980s Spotify had ranked hip-hop by people’s initial distaste, the genre might have been buried before it ever got off the ground.

    I spent years in e-learning and watched my own son disappear into video games that were engineered to keep him engaged minute by minute, and this paper put words to something I’d half-noticed for a long time. The systems that are best at giving us what we want right now can be terrible at helping us become people with bigger, richer tastes later. There’s a real difference between a tool that satisfies you and a tool that helps you grow.

    So what can you actually do with this? Be your own source of randomness. Once in a while, hand the keys to a human — a friend’s playlist, a librarian’s pick, a critic whose taste runs different from yours. Deliberately rest the songs and shows you love instead of binging them flat. And when an algorithm keeps serving you the same comfortable loop, treat that as a signal to go wander somewhere it would never send you. The boredom you’re feeling might not be a sign that there’s nothing good left — it might just be a sign that you’ve been fed the same thing one too many times.

    If you’re studying psychology, scroll down — I’ve pulled out the key concepts this research illustrates, with plain-language definitions you can use for an exam.

    Psychology Terms in This Article

    Mere exposure effect — The tendency to develop a preference for things simply because we’ve encountered them repeatedly. This study is built on the upside of that effect: the more you’re exposed to a style of music or art, the more you learn to appreciate it. The twist is that the same familiarity that builds liking eventually overshoots into boredom — so an algorithm that maximizes familiar content rides the mere exposure effect right past its sweet spot.

    Habituation (satiation) — A decrease in responsiveness to a stimulus after repeated or prolonged exposure. In the model, listeners get “sick of” a favorite song because their response to it weakens every time it’s replayed. Knight’s “straddling” trap is essentially habituation in action: the algorithm keeps replaying a great song until the listener habituates, never realizing a rest period would reset the response.

    Reinforcement — In operant conditioning, any consequence that strengthens the behavior it follows. Recommendation systems treat your clicks and plays as reinforcement signals, “rewarding” whatever you engage with by serving more of it. The paper shows the danger of a system that only follows immediate reinforcement: it optimizes for the next click while quietly narrowing the range of things you’ll ever enjoy.

    Sensation seeking — A personality trait describing the drive to pursue novel, varied, and stimulating experiences. The research highlights what gets lost when an algorithm refuses to explore: the novelty that lets tastes evolve. The “noise” that improved long-term satisfaction in the simulation is essentially a manufactured dose of novelty — the thing sensation seeking naturally pushes us toward and that over-precise systems strip away.

    References

    Knight, S. (2026). Engagement-based curation and the evolution of taste. Journal of Cultural Economics. https://doi.org/10.1007/s10824-026-09591-3

    Reporting by Eric W. Dolan, PsyPost (June 2, 2026).

  • Does Spoiling Your Kids Actually Create Narcissists? Here’s What the Research Says

    Does Spoiling Your Kids Actually Create Narcissists? Here’s What the Research Says

    You’ve probably heard it before — maybe you’ve even said it yourself: “That kid is going to grow up to be a real handful.” We have a strong gut sense that giving children everything they want, never saying no, removing every obstacle before they can encounter it — all of that leads to something dark in adulthood. But is that actually true? And more interestingly, what specifically does it lead to?

    A new study published in Current Psychology took a careful look at exactly this question. Researchers Jennifer Vonk, Virgil Zeigler-Hill, and Nyla Griffin at Oakland University asked 720 college students to recall how their parents treated them during childhood — specifically whether their caregivers offered praise, gave them whatever they wanted (indulgence), or pushed them toward status and prestige. Then they measured something called the Dark Triad: three personality dimensions that psychologists consider socially difficult — psychopathy, Machiavellianism, and narcissism.

    What they found is striking — and the key is in the distinction between two things parents often confuse: praise and indulgence. These are not the same thing, and it turns out they lead to very different outcomes. Recalled childhood praise — being told you are valued, capable, and worthwhile — predicted lower levels of hostility, impulsivity, and cruelty in adulthood. It was associated with what the researchers call adaptive social traits: healthy confidence, social agency, and emotional stability. Praise, it seems, builds people up in a genuinely useful way.

    Recalled childhood indulgence — being given everything you asked for, having no real limits set, being treated as though rules don’t apply to you — predicted something very different. Higher psychopathic meanness. Higher narcissistic antagonism. Higher impulsivity, or what researchers call disinhibition: acting on impulses without considering consequences. The child who was never told “no” grew up with less capacity to regulate behavior and a greater tendency toward cruelty and entitlement.

    What makes this research stand out is how precisely it breaks down these personality dimensions. Rather than treating narcissism or psychopathy as a single block, the researchers measured specific facets — antagonism, emotional vulnerability, boldness, meanness — and found that indulgence and praise had opposite effects on nearly every one of them. As lead researcher Vonk told PsyPost: “The fact that high indulgence and low praise seem to predict higher levels of pathological traits… points to the importance of providing children with affirming feedback without engaging in over-indulgence.”

    I find this genuinely useful — not just as a piece of research, but as a practical distinction. We tend to think of giving kids positive experiences as one thing. But there is a real difference between affirming a child’s worth and removing every obstacle from their path. One builds self-esteem — an authentic sense of one’s own value that doesn’t depend on always getting what you want. The other builds entitlement, which is something else entirely.

    Of course, the study has limits. It relied on how adults remember their childhoods, which isn’t the same as how those childhoods actually were. Memory is reconstructive, and people high in hostile traits may simply recall their parents more negatively. The sample was also mostly white, female, and American college students — so we should be cautious about generalizing. But the pattern is consistent with what developmental psychologists have suspected for a long time.

    If you’re studying psychology, I’ve pulled out the key concepts this research illustrates — scroll down to the terms section.

    Psychology Terms in This Article

    Narcissistic personality disorder — A pattern of grandiosity, a deep need for admiration, and a lack of empathy for others. In this study, childhood indulgence predicted higher scores on narcissistic antagonism — a facet involving entitlement, hostility toward others, and exploitation. This shows how overindulgence may feed the entitlement component of narcissism without producing the full clinical disorder.

    Antisocial personality disorder — Characterized by disregard for others’ rights, impulsivity, deception, and lack of remorse. The psychopathic meanness and disinhibition facets measured in this study overlap directly with antisocial traits. The finding that indulgence predicted higher meanness and impulsivity suggests that failing to set limits during development may contribute to the callousness and poor impulse control seen in antisocial behavior.

    Self-esteem — A person’s overall evaluation of their own worth and value. The study found that parental praise predicted lower hostile traits and higher social confidence — essentially healthier self-esteem. This supports the idea that self-esteem built on authentic affirmation functions very differently from the inflated self-regard produced by overindulgence.

    Trait — A relatively stable characteristic that influences how a person thinks, feels, and behaves across situations. This study used a multi-dimensional trait approach, measuring specific facets of the Dark Triad rather than treating psychopathy or narcissism as single traits. When psychologists study personality, they increasingly break broad traits into narrower components, because different facets can have entirely different developmental origins.

    Nature-nurture issue — The long-standing debate about whether psychological characteristics are shaped more by genetic inheritance or by environmental experience. This study is firmly on the nurture side — it examines how specific parenting behaviors correlate with adult personality outcomes. That said, children’s pre-existing temperaments may influence both how parents treat them and how they recall that treatment in adulthood, which is the nature-nurture issue in action.

    Temperament — The early-appearing, biologically influenced emotional dispositions that form the foundation of personality. A child’s temperament may partly drive parenting behavior — a difficult child may elicit different parenting than an easy one. This is why correlational studies like this can’t fully separate what parents cause from what parents respond to.

    References

    Vonk, J., Zeigler-Hill, V., & Griffin, N. (2026). Praise the light, indulge the dark: Parenting strategies and dark personality traits. Current Psychology. https://doi.org/10.1007/s12144-026-09418-6

    Dolan, E. W. (2026, May 30). New study links parental indulgence to psychopathic and narcissistic traits in adulthood. PsyPost.

  • Personality Scale

    Personality Scale

    What does the way you draw a tree reveal about your personality? That’s the premise behind the Baum Test — a projective personality assessment developed by Swiss psychologist Charles Koch in 1949. The idea is deceptively simple: the choices you make when sketching a tree, the shape of the trunk, how you draw the branches, whether the roots are visible, are thought to reflect something about your inner psychological world. A colleague of mine who specializes in projective assessment has been refining an updated version of this technique and has asked for help gathering data from as many people as possible. The activity takes about three minutes. You’ll draw a single tree, and the system will generate a personality profile based on what you draw. At the end, you’ll be asked to rate how accurately the profile describes you. Give it a try.

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  • “I’m Getting Old” — And That Thought Might Be Killing You

    “I’m Getting Old” — And That Thought Might Be Killing You

    Do you catch yourself saying “I’m getting old” more than you’d like to admit? Turns out, that habit might be doing more damage than you think. Psychologist Becca Levy of Yale has spent decades studying how our aging mindset — the beliefs we hold about what getting older actually means — shapes how we physically and cognitively age. In a study following more than 11,000 older Americans over twelve years, nearly half showed improvement in either cognitive or physical function, a story that gets completely buried when you only look at averages. Her earlier research found that people with a positive aging mindset lived 7.5 years longer on average than those with negative views — a bigger effect than the difference between having high or normal cholesterol. The mechanism behind this is a process called stereotype embodiment: the cultural messages we absorb about old age become self-fulfilling prophecies through three pathways — psychological, behavioral, and physiological. That last one involves chronic stress and elevated cortisol levels that, over time, actually shrink the hippocampus and accelerate biological aging. I also look at Ellen Langer’s famous Counterclockwise study, one of psychology’s most striking demonstrations of the mind-body connection, and what the concept of neuroplasticity tells us about our capacity for growth at any age. Plus, I talk honestly about my own complicated feelings about getting older — and what the research suggests we can actually do about them.

    References

  • Levels of Processing Activity

    Levels of Processing Activity

    Levels of Processing: An Online Memory Activity

    Levels of Processing

    An Activity On How Your Memory Works

    You Are About to Run a Memory Study on Yourself

    Actors who memorize scripts don’t succeed by repeating lines over and over. Research shows they do something different: they focus on meaning. The deeper they process a line — understanding motivation, emotion, and context — the better it sticks.

    Psychologist Fergus Craik called this levels of processing. Shallow processing (noticing appearance) leads to weak memories. Deep processing (thinking about meaning) leads to strong ones.

    ⚠️ Important: You will see 8 words, one at a time. For each word, answer a simple question — yes or no. You are not being asked to memorize anything. Just answer the question honestly.

    After all 8 words, there will be a recall test. You’ll try to write down as many words as you can remember.

    Word 1 of 8

    Surprise Recall Test

    Without looking back, type as many of the 8 words as you can remember. Spelling counts — type carefully.

    Your Results

    Here’s what your memory activity reveals

    Shallow
    —
    out of 3 words
    Moderate
    —
    out of 2 words
    Deep
    —
    out of 3 words

    Recall by Processing Depth

    Shallow
    Moderate
    Deep

    The Psychology Behind What Just Happened

    The actor Michael Caine described this same process when he said that the best performance comes from listening to other actors rather than mentally rehearsing your next line. An actor focused on meaning is doing deep processing in real time — and that is exactly why the lines are there when needed.

    When you answered questions about meaning (does this word fit a sentence?), you built richer, more connected memory traces. Those connections became retrieval cues. Shallow questions left far fewer hooks in memory.

    All 8 Words

  • The Psych Files – Most Popular Episodes

    I’ll bet you’re looking for one of these episodes. They are my most popular and the ones that really make me proud (if you’re looking for some other previous episode/blog post on this site, please contact me at: mikrbritt at mac dot com):