Category: psychology

Three Observations About Walking and Learning

Seth Roberts5 Comments

1. Studying Chinese-character flashcards while walking on a treadmill is as pleasant as drinking something when thirsty. Unlike actual thirst and drinking, the pleasure lasts a long time and the desire is under your control (to turn it on, you start walking; to turn it off, you stop).

2. What is the opposite of betrayal? There is no antonym. The opposite is so rare it isn’t even obvious what it is. Betrayal is when your friend becomes your enemy; the opposite is when your enemy becomes your friend. Living in China and not knowing Chinese was not exactly my enemy but it was certainly negative. This treadmill discovery turns it into a positive: Chinese becomes an inexhaustible source of dry knowledge that I can enjoy learning.

3. Learning is the central theme of experimental psychology and perhaps all academic psychology. Psychology professors have done more experiments about learning than anything else. Practically all of those experiments have been about efficiency of learning: The amount of learning (e.g., percent correct) in Condition A is compared with the amount of learning in Condition B, where A and B “cost” about the same. As a result, we know a great deal about what controls efficiency of learning, at least in laboratory tasks. I think many psychologists are surprised and disappointed that this research has had little effect outside academia. I have never heard a good answer to the question of why. If you’d asked me a month ago I would have said it’s because they haven’t discovered large non-obvious effects. That’s true, but says nothing about how to discover them.

My treadmill experience suggests a more helpful answer: Hedonics matter. Learning exactly the same material can be more or less pleasant. When Learning X is pleasant, it is learned easily; when Learning X is unpleasant, it is learned with difficulty or not at all. In the real world, hedonic differences matter more than efficiency differences. If they want to improve real-world learning, psychologists have been measuring the wrong thing. It is a hundred times easier and ten times more “objective” (= “scientific”) to study how much has been learned than to study how pleasant was the experience. But that doesn’t mean it is better to study.

Michel Cabanac, a physiologist, strikes me as someone on the right path. Cabanac has studied how the pleasantness of this or that experience goes up or down to help us properly self-regulate. A simple example is that cold water feels more pleasant when we feel hot than when we feel cold. A common example is that exactly the same food becomes less pleasant during a meal. The food doesn’t change; we change.

Feeling the Future: More Likely Than You Think

Seth Roberts9 Comments

A few posts ago I pointed out how Daryl Bem’s Feeling the Future paper (experiments that seem to show the future changing the present) could have been more persuasive. This post is the other side of my critique. I’ll explain why the results are more persuasive than Bem and commentators have said.

If this research is correct, I told my students, you can study for a test not only before but also after you take it. Studying after is better than studying before because you would only need to study what was on the test. And there are reasons to believe the research that Bem didn’t mention:

First, the history of electricity. Electricity, now incredibly important, was once nearly invisible. Remember Galvani? During a frog dissection, an assistant touched an exposed leg-muscle nerve with a static-electricity-charged scalpel. The leg twitched. This tiny accident made all the difference. Galvani studied what had happened. He soon discovered that two different metals in contact generated electricity. This led to the first batteries. With a steady source of electricity, we could learn about it.

The methodological lesson is that the nervous system is (a) unusually sensitive to the environment and (b) easy to “read”. You could touch a static-charged knife to many things: a plant, cloth, a piece of metal, a piece of wood. No doubt this had happened countless times before Galvani. The static electricity changed all of them (plant, etc.) but these changes led nowhere because they were too small to see. In contrast, the effect of static electricity on the nervous system was easy to see. It was amplified by the neuro-muscular junction and the muscle. Measuring the effect of electricity on nerves turned out to be the best way to study it, at first.

My self-experimentation takes advantage of the sensitivity of the brain to the environment. Mostly I study stuff controlled by the brain, such as sleep, weight, and arithmetic speed. Because the brain changes quickly and the changes are easy to detect (via behavior), I can do short convincing experiments. People who study health in other ways have to do much slower and more difficult experiments. For example, bones change slowly in response to dietary changes. Other parts of our body, such as the liver, are much harder to measure than behavior.

The story of how electricity began to be understood suggests that if the future does affect the present, there will be a period when the best way to study this is by studying behavior. This is what Bem did. We don’t normally think of the brain as good for physics experiments but Galvani showed the truth of this. The brain acts as an enormously sensitive amplifier. For example, Barbara Sakitt did an experiment suggesting that the eye can detect single photons. Bem’s experiments cost essentially nothing. He needed no grant. For a physicist to build a detector that detects future effects on the present without involving the brain will surely be more expensive and more difficult, just as it was so much easier for Galvani to use frog legs than build a electricity detector not involving the nervous system.

Second, the history of psi research. Unfortunately Bem omitted even a brief summary from his article. Experiments similar to Bem’s have been going on for decades. In the 1980s, I visited a lab near Princeton doing such experiments. I haven’t studied this research but as far as I know they have repeatedly reported small effects. This is what has kept them going — or at least I cannot rule out this explanation for why it has lasted so long. The alchemists pursued fruitless research a long time but I am unaware they reported small successes. Bem used his knowledge of mainstream psychology (e.g., priming) to design much more sensitive experiments. So it makes sense that these weak effects would become more detectable.

Third, gravity/time symmetry. Bem says we see no signs of the future affecting the present in everyday life. I am less sure. The effects of gravity and time reversal (time going backwards) are remarkably similar. If you watch the same video played forwards and backwards you can tell which is forward (correct) and which is time-reversed: In the time-reversed version, impossible things happen. A man slowly drinks coffee. Correct version: the level of coffee in his cup slowly gets lower, as the coffee goes into his mouth. Time-reversed version: the level of coffee in his cup slowly gets higher, as the coffee comes out of his mouth into the cup. That’s impossible! You can spit again and again into a cup, sure, but you can’t spit pure coffee into a cup. You can’t unmix the coffee from the rest of the liquid in your mouth.

Imagine two billiard balls on a frictionless perfectly flat pool table. They are together in the center. Touching, but not held together. A video of the balls would show them slowly moving apart in response to random disturbances. They move down a probability gradient: Further apart is more likely than close together. This is why a sodium pump is needed to keep enough sodium in cells: because the difference in concentration (more sodium within a cell) makes diffusion out of the cell more likely than diffusion into the cell.

Now we do something different: we randomly and independently place both balls on the table. The placement of one has no effect on the placement of the other. Almost surely they will not be touching. Then we start filming. And a funny thing happens: the balls move closer and closer together! The opposite of the first film, where they slowly drifted apart. They are drifting closer and closer together because they are so heavy that the gravitational attraction is larger than the random forces (e.g., air molecules) in the situation. The second film run backwards looks exactly like the first film run forward! In this way the force of gravity causes time to go backwards. It causes seemingly less-probable events to be more probable than seemingly more-probable events. Rather than have two concepts (force of gravity, passage of time) perhaps we only need one.

I will write more about this later. The simple point is that the effects of gravity are very similar, perhaps identical, to time moving backwards. The force of gravity is obvious and the similarity to backwards time unexplained. Given this failure to explain something easy to see, we shouldn’t be sure we know if the future can visibly affect the present. If time goes backwards to some extent (measured by the force of gravity) then to some extent the future has happened and we know something about it. The more we know about it, the better we can choose to study for a test by studying just the items that will appear on it.

Feeling the Future: Room For Improvement

Seth Roberts3 Comments

My Frontiers of Psychology class read Daryl Bem’s new paper Feeling the Future that reports nine experiments that show an effect of the future on the present. I have a different take than anything I’ve read: I think there are several good reasons to take it seriously. But in this post let’s start with how it could have been better:

1. Lack of background. There have been lots of experiments along these lines. What did they show? This question is not clearly answered. The prior probability of these claims is enormously important. As I told my students, if seeing the future was common and easy for even a small fraction of people, we wouldn’t have businesses, such as casinos, making money on gambling. But the existence of such businesses doesn’t rule out weak effects.

2. Lack of exact repetition. An obvious criticism is that Bem slanted the data analysis to favor the results he wanted. In any data analysis of unfamiliar data, you must choose — how to transform the data, what test to use, and so on. You must also choose how many subjects to run and how many trials to give them. There are rules for these choices (Bem doesn’t seem to know how to choose a transformation) but nevertheless they allow favoritism to creep in. Drug trials have big problems along these lines — severe slanting of the analysis to make the results more favorable — which is why when you register a clinical trial you must specify the endpoints. The answer to the criticism that your data-analysis choices made your favored result more likely is to do a data analysis with no choices at all. This cannot be done from scratch. You need to do the experiment once, make all the necessary choices, and then do the same experiment again (same everything as much as possible) and analyze the data exactly the way you analyzed the data from the first experiment. Bem never does this. Instead each experiment is different from all the rest. This is what experimental psychologists traditionally do but here it is a bad idea. Better to have taken the two simplest and clearest effects (priming and word learning) and repeated them several times exactly.

3. Were experiments left out? Let’s say you observe a weakly-significant result, p = 0.03. Now you do the same experiment eight more times. How likely is it that each of the eight replications will also find a significant difference? Quite low. Yet Bem finds a weakly significant difference in each of his nine experiments. This is highly unlikely. Bem appears unaware of the problem. Mendel had the same problem (data too good to be true). Ultimately Mendel was proved right. But again it stresses that Bem should do exact repetitions and report the results no matter what if he wants to be more persuasive.

Assorted Links

Seth Roberts3 Comments
  • Plagiarism by Dr. Shervert Frazier, a Harvard psychiatrist and at one point director of the National Institute of Mental Health
  • David Shenk on talent & genius: why rely on homilies when we have data?
  • Should practice tests have warning labels? Apparently. A University of Central Florida business professor creates a test using a test bank, tells students he wrote the test, and says students who studied questions from the test bank are cheaters!

Why I Am A Biological Psychologist

Seth Roberts12 Comments

Sheena Iyengar, a professor at Columbia Business School, is best-known for a study she did in graduate school. When shoppers in a Menlo Park food store were offered much more choice of jams (24 rather than 6), they were less likely to buy one. In The Art of Choosing (2010), Iyengar wrote (p. 190):

Since publication of the jam study, I and other researchers have conducted more experiments on the effect of assortment size. These studies, many of which were designed to replicate real-world choosing contexts, have found fairly consistently that when people are given a moderate number of options (4 to 6) rather than a large number (20 to 30), they are more likely to make a choice, are more confident in their decisions, and are happier in what they choose.

In contrast, Benjamin Scheibehenne, a research scientist at the University of Basel, and two co-authors, who surveyed the literature, found the effect was hard to replicate:

The choice overload hypothesis states that an increase in the number of options to choose from may lead to adverse consequences such as a decrease in the motivation to choose or the satisfaction with the finally chosen option. A number of studies found strong instances of choice overload in the lab and in the field, but others found no such effects or found that more choices may instead facilitate choice and increase satisfaction. In a meta-analysis of 63 conditions from 50 published and unpublished experiments (N = 5,036), we found a mean effect size of virtually zero but considerable variance between studies

This reminds me of the learned-helplessness effect. When Martin Seligman, a psychology professor at Penn and recent president of the American Psychological Association, was a graduate student, he and his advisor reported that when you give dogs inescapable shock, they stop trying to escape or avoid the shock: learned helplessness. The effect turned out to be extremely hard to replicate, but this did not stop Seligman from having a brilliant career.