Two Minds Blog

  I have written previously about the link between exercise and mood, including the consistent research finding that aerobic exercise is just as effective in treating depression as either psychotherapy or medication. This week, I'm excited to share a new multi-national research collaboration that I was able to participate in, looking at the mood-exercise linkage in a different way.  In our  just-published article , a German research team conducted a within-person meta-analysis, meaning that they merged raw data from 69 different studies across 14 countries to draw overall conclusions. Each of these studies (including one of mine ) measured exercise parameters using an accelerometer -- either a research-grade device like Actigraph, or a commercial-grade tracker such as a Fitbit, AppleWatch, or Garmin wristband. Each of the studies also collected daily survey data on a measure of mood or subjective well-being. The combination of daily exercise tracking with daily survey da...

When I'm not reading psychology or history, I gravitate toward sci-fi and fantasy works (as you might have surmised from my March 2026 posts about telepathy and mind uploading). A writer whose work consistently feeds my inner geek is Brandon Sanderson, author of the Mistborn  and Stormlight Archive  series, as well as the Alcatraz versus the Evil Librarians books that my daughter enjoyed in elementary school, and for those of us of a certain age, also the completer of Robert Jordan's Wheel of Time . In addition to his excellent novels, Mr. Sanderson has developed quite a large side hustle selling Sanderverse-themed merchandise , hosting his own annual convention , and other ancillary businesses. But something that I have always admired is his willingness to give some of his work away -- early on, in the form of a "free sample" novel for people to discover whether they liked him, and a blog where he would write about his own writing process. More recently, he announced...

Before psychology, and still concurrent with it, the need to help people with their behavior-change endeavors, mental health concerns, and other problems in living was met by the world’s great religions. For many people religions still serve this purpose, often outside the Western scientific view that considers them unfalsifiable and therefore irrelevant. This scientific myopia means that psychology has a limited perspective on behavior-change practices of religious derivation -- since the time of William James's Varieties of Religious Experience , religion hasn't been considered a respectable area of study. (Interestingly, we have better data about non-Western practices like yoga and meditation, which have been studied in ways cut off from their religious origins. It is mainly Christianity that was seen as outside the purview of scientific comment). One traditional practice common to many religions is the pilgrimage , a journey from home to a distant location in order to view...

My most recent blog post suggested that we aren't going to be able to upload human consciousness to the cloud anytime soon, for various reasons that have to do with the technical differences between human and AI information processing, and the physical differences between computers and human brains. So what about a simpler task, reading people's minds? That's another common trope of fantasy and sci-fi literature, and it seems close to recent advances in the mental control of prosthetic devices . The Neuralink company has also reported successes in this area, along with some ability for people with communication impairments to generate words or phrases on a computer. This seems like it is getting close to reading people's thoughts. Let's leave aside the medical challenges of implanting electrodes in the brain, which are considerable: metal needles can damage sensitive brain tissue, so the body treats the electrode as an injury and attempts to build scar tissue aroun...

It’s a popular sci-fi trope : The human consciousness now residing in a computer, trading physical life for machine-based immortality. In The Matrix this works both ways: You can not only upload your consciousness to a vast multiplayer online world, but also instantly download digitized knowledge from the cloud to your brain (“ I know kung fu! ”). A digitized consciousness might have some acknowledged limitations, sure – you don’t eat anymore, and you can’t smell the flowers. Even that seems ridiculous by modern technology standards, though: Couldn’t we design appropriate sensors, or simply simulate those experiences? Indeed, there’s a school of thought that claims we are already living in some type of simulated reality , whether computer-generated or otherwise. Let’s confine ourselves to currently existing digital technologies, and examine the question of whether it really might be possible to upload our consciousness to the cloud. China is investing a lot in brain-computer interf...

In this post, I will take a look at the Behavior Change Wheel (BCW), a newer framework for understanding health behavior. The model has been around for a decade, but it became much better-known after the book Engaged   featured it in 2020. The BCW model is sometimes called by the name of one of its components, like "the COM-B model." Technically COM-B is just part of the full model diagram, shown above (the green inner circle), so I'm going to refer to the full framework as "the BCW" in this post. As you will see, it might be possible to utilize or accept just one of the BCW's components without necessarily buying into the whole thing. I'm also going to call the BCW a "framework" or "model" instead of a theory. That part comes directly from its creators, who describe the BCW as "a synthesis of 19 frameworks of behavior change found in the research literature" ( Mitchie, Atkins, & West , p. 11). The 19 frameworks are als...