Two Minds Blog

If you use any type of personal sensor device like a smart watch or a fitness tracker, you are probably already familiar with the concept of heart rate variability  or HRV. You might have seen this statistic interpreted in many different ways -- as a measure of cardiovascular fitness, of stress, of mindfulness or resilience in the face of stress, or even of risk for negative cardiovascular events like heart attack and stroke. What is HRV, and what does it mean? HRV is a measure based on the  duration between one heartbeat and the next . This is usually measured in milliseconds per beat -- so, for instance, if your heart beats 60 times per minute, then the average interval between two heartbeats is 100 milliseconds (60 seconds / minute x 1 minute / 60 beats = 1 second per beat or 100 ms per beat). The heart has an off-beat as the chambers expand and contract in rhythm, so the technical definition is based on the type of ticker-tape record of heartbeats that's produced by...

Daniel Kahneman and Amos Tversky's behavioral economics work led to a 2002 Nobel Prize based on the fundamental idea that people's decision-making is not entirely rational. Two Minds Theory builds on and expands this notion by suggesting (a) that our actual behaviors are produced by the intuitive mind rather than the narrative mind, and (b) that our narratives themselves can be flawed based on factors like moral judgments or strong desire for a particular outcome . In one sense this doesn't seem surprising, but it sometimes leads to a fundamental question about human nature: If we can't trust reason to give us the right answers, how do can we actually know anything ? The classical distinction between reason and emotion suggested that people should be guided by thoughts and not by feelings; indeed, much of our legal system is based on this distinction. Economics dating back at least as far as the utilitarianism of Jeremy Bentham and John Stuart Mill was based on the i...

This week I have a personal story about my own experience of two independent minds inside my own head. It began with a bad car accident in 2016: My 6-year-old daughter and I were hit head-on by a car going about 50 miles per hour that ran a red light. We spun and crashed into the car behind us. We both had some broken bones and my daughter needed surgery, but we lived. My wife was the first to notice that something was wrong with my thinking. I mixed up the dosage on medications for our daughters, twice. That's unusual because I typically have a good awareness about medications -- adherence is one of my main areas of research. As I returned to work we noticed that I was getting more and more tired, to the point where I would have to lie down after dinner or some days even before dinner. Three months after the accident, I was regularly napping in the middle of the day. I was also having a hard time concentrating or following the thread of a conversation, and I was forgetting...

If you take a close look at your local or state-level data on the incidence of coronavirus, you might see an interesting up-and-down pattern. Notice the spikes and valleys marked with arrows on the graph of my county's data above: Cases don’t simply grow or decrease, they wobble around. Public health experts use 3- or 7-day moving averages to smooth out these bumps, but you can see peaks and dips in the fitted lines as well. Sometimes one of the spikes leads to exponential growth, as happened in many places in June, and may take months to come back down again. Unfortunately, we probably won’t know that the next increase is more than a temporary increase until it’s too late to change things. The cyclical ups and downs suggest that something is wrong with our approach to the COVID-19 pandemic. I believe that this comes out of a basic property of the human risk-perception system, which leads us to be reactive rather than proactive in our health decision-making. We give too much weight...

Language is a brain function that we can clearly identify with the Narrative system. Consciousness is one hallmark of the Narrative system, and we often experience conscious thought in our native language, perhaps even if we use a different form of speech in our daily lives. Many people report knowing that they "truly" had learned a foreign language when they suddenly found themselves thinking in it, for instance during a long trip to another country. Another typical Narrative characteristic is an inability to multitask. Many people find that they can write while listening to music but not to talk radio, because the receptive and expressive language functions interfere with one another. Language also has the characteristic abstractness of the Narrative system, allowing for categories within categories like "animal -> mammal -> dog -> miniature poodle." Based on all of these characteristics, we would expect language to be based in the higher cortical a...

It has been said that if you find one human, chances are good that you can find another one within 10 feet. (The most completely alone man in history was probably astronaut Michael Collins, orbiting the moon by himself in the Apollo 11 command module while his colleagues Neil Armstrong and Buzz Aldrin were down on the surface; at his furthest rotation from the landing site he would have been about 2,200 miles away, and that lasted only a second or two before he started to approach them again). I have argued that the Narrative mind is particularly good at telling stories about  social  situations -- our interactions with others -- because we are fundamentally social animals. But why  are we so interested in other humans? The mental projections we make about social interactions seem to be produced by the Narrative mind, but our basic orientation toward others comes from a more Intuitive process. In the book Who's In Charge? Free Will and the Science of the Brain , n...

We've had lots of conversation in our household lately on the question of whether to open schools for in-person learning this fall. Even if you don't have children or grandchildren affected, this is a broad question of public health: Not only  should we personally go back?  but also  should anyone be allowed to go back given the current state of the pandemic?  or even should anyone be allowed to keep their kids at home? (e.g., based on hypothesized risks to mental health or learning).   These are difficult questions because they involve competing goals such as education versus health, parents' work demands versus children's support needs, and also because they must be made with limited information and under time constraints. These two features make real-world decisions particularly difficult, as I described in a recent post about naturalistic decision-making . Another framework that may be helpful as we think about whether to re-open school buildings ...