Believing everyone else is wrong is a danger sign

I have a guest post for the Research Digest, snappily titled ‘People who think their opinions are superior to others are most prone to overestimating their relevant knowledge and ignoring chances to learn more‘. The paper I review is about the so-called “belief superiority” effect, which is defined by thinking that your views are better than other people’s (i.e. not just that you are right, but that other people are wrong). The finding that people who have belief superiority are more likely to overestimate their knowledge is a twist on the famous Dunning-Kruger phenomenon, but showing that it isn’t just ignorance that predicts overconfidence, but also the specific belief that everyone else has mistaken beliefs.

Here’s the first lines of the Research Digest piece:

We all know someone who is convinced their opinion is better than everyone else’s on a topic – perhaps, even, that it is the only correct opinion to have. Maybe, on some topics, you are that person. No psychologist would be surprised that people who are convinced their beliefs are superior think they are better informed than others, but this fact leads to a follow on question: are people actually better informed on the topics for which they are convinced their opinion is superior? This is what Michael Hall and Kaitlin Raimi set out to check in a series of experiments in the Journal of Experimental Social Psychology.

Read more here: ‘People who think their opinions are superior to others are most prone to overestimating their relevant knowledge and ignoring chances to learn more


Review: John Bargh’s “Before You Know It”

I have a review of John Bargh’s new book “Before You Know It: The Unconscious Reasons We Do What We Do” in this month’s Psychologist magazine. You can read the review in print (or online here) but the magazine could only fit in 250 words, and I originally wrote closer to 700. I’ll put the full, unedited, review below at the end of this post.

John Bargh is one of the world’s most celebrated social psychologists, and has made his name with creative experiments supposedly demonstrating the nature of our unconscious minds. His work, and style of work, has been directly or implicitly criticised during the so-called replication crisis in psychology (example), so I approached a book length treatment of his ideas with interest, and in anticipation of how he’d respond to his critics.

Full disclosure: I’ve previously argued that Bargh’s definition of ‘unconscious’ is theoretically incoherent, rather than merely empirically unreliable, so my prior expectations for his book are probably best classified as ‘skeptical’. I did get a free copy though, which always puts me in a good mood.

If you like short and sweet, please pay The Psychologist a visit for the short review. If you’ve patience for more of me (and John Bargh), read on….

Continue reading “Review: John Bargh’s “Before You Know It””

Did the Victorians have faster reactions?

Psychologists have been measuring reaction times since before psychology existed, and they are still a staple of cognitive psychology experiments today. Typically psychologists look for a difference in the time it takes participants to respond to stimuli under different conditions as evidence of differences in how cognitive processing occurs in those conditions.

Galton, the famous eugenicist and statistician, collected a large data set (n=3410) of so called ‘simple reaction times’ in the last years of the 19th century.  Galton’s interest was rather different from most modern psychologists – he was interested in measures of reaction time as a indicator of individual differences. Galton’s theory was that differences in processing speed might underlie differences in intelligence, and maybe those differences could be efficiently assessed by recording people’s reaction times.

Galton’s data creates an interesting opportunity – are people today, over 100 years later, faster or slower than Galton’s participants? If you believe Galton’s theory, the answer wouldn’t just tell you if you would be likely to win in a quick-draw  contest with a Victorian gunslinger, it could also provide an insight into generational changes in cognitive function more broadly.

Reaction time [RT] data provides an interesting counterpoint to the most famous historical change in cognitive function – the generation on generation increase in IQ scores, known as the Flynn Effect. The Flynn Effect surprises two kinds of people – those who look at “kids today” and know by instinct that they are less polite, less intelligent and less disciplined their own generation (this has been documented in every generation back to at least Ancient Greece), and those who look at kids today and know by prior theoretical commitments that each generation should be dumber than the previous (because more intelligent people have fewer children, is the idea).

Whilst the Flynn Effect contradicts the idea that people are getting dumber, some hope does seem to lie in the reaction time data. Maybe Victorian participants really did have faster reaction times! Several research papers  (1, 2) have tried to compare Galton’s results to more modern studies, some of which tried to use the the same apparatus as well as the same method of measurement. Here’s Silverman (2010):

the RTs obtained by young adults in 14 studies published from 1941 on were compared with the RTs obtained by young adults in a study conducted by Galton in the late 1800s. With one exception, the newer studies obtained RTs longer than those obtained by Galton. The possibility that these differences in results are due to faulty timing instruments is considered but deemed unlikely.
Woodley et al (2015) have a helpful graph (Galton’s result shown on the bottom left):
(Woodley et al, 2015, Figure 1, “Secular SRT slowing across four large, representative studies from the UK spanning a century. Bubble-size is proportional to sample size. Combined N = 6622.”)

So the difference is only ~20 milliseconds (i.e. one fiftieth of a second) over 100 years, but in reaction time terms that’s a hefty chunk – it means modern participants are about 10% slower!

What are we to make of this? Normally we wouldn’t put much weight on a single study, even one with 3000 participants, but there aren’t many alternatives. It isn’t as if we can have access to young adults born in the 19th century to check if the result replicates. It’s a shame there aren’t more intervening studies, so we could test the reasonable prediction that participants in the 1930s should be about halfway between the Victorian and modern participants.

And, even if we believe this datum, what does it mean? A genuine decline in cognitive capacity? Excess cognitive load on other functions? Motivational changes? Changes in how experiments are run or approached by participants? I’m not giving up on the kids just yet.


spaced repetition & Darwin’s golden rule

Spaced repetition is a memory hack. We know that spacing out your study is more effective than cramming, but using an app you can tailor your own spaced repetition schedule, allowing you to efficiently create reliable memories for any material you like.

Michael Nielsen, has a nice thread on his use of spaced repetition on twitter:

He covers how he chooses what to put into his review system, what the right amount of information is for each item, and what memory alone won’t give you (understanding of the process which uses the memorised items). Nielsen is pretty enthusiastic about the benefits:

The single biggest change is that memory is no longer a haphazard event, to be left to chance. Rather, I can guarantee I will remember something, with minimal effort: it makes memory a  choice.

There are lots of apps/programmes which can help you run a spaced repetition system, but Nielsen used Anki (, which is open source, and has desktop and mobile clients (which sync between themselves, which is useful if you want to add information while at a computer, then review it on your mobile while you wait in line for coffee or whatever).

Checking Anki out, it seems pretty nice, and I’ve realised I can use it to overcome a cognitive bias we all suffer from: a tendency to forget facts which are an inconvenient for our beliefs.

Charles Darwin notes this in his autobiography:

“I had, also, during many years, followed a golden rule, namely, that whenever a published fact, a new observation or thought came across me, which was opposed to my general results, to make a memorandum of it without fail and at once; for I had found by experience that such facts and thoughts were far more apt to escape from the memory than favourable ones. Owing to this habit, very few objections were raised against my views which I had not at least noticed and attempted to answer.”

(Darwin, 1856/1958, p123).

I have notebooks, and Darwin’s habit of forgetting “unfavourable” facts, but I wonder if my thinking might be improved by not just noting the facts, but being able to keep them in memory – using a spaced repetition system. I’m going to give it a go.

Links & Footnotes:

Anki app (

Wikipedia on space repetition systems

The Autobiography of Charles Darwin, 1809–1882, edited by Nora Barlow. London: Collins

For more on the science, see this recent review for educators: Weinstein, Y., Madan, C. R., & Sumeracki, M. A. (2018). Teaching the science of learning. Cognitive research: principles and implications, 3(1), 2.

I note that Anki-based spaced repetition also does a side serving of retrieval practice and interleaving (other effective learning techniques).

A graph that is made by perceiving it

The contrast sensitivity function shows how our sensitivity to contrasts is affected by spatial frequency. You can test it using gratings of alternating light and darker shade. Ian Goodfellow has this neat observation:

It’s a graph that makes itself! The image is the raw data, and by interacting with your visual system, you perceive a discontinuity which illustrates the limits of your perception.

Spatial frequency means how often things change in space. High spatial frequency changes means lots of small detail.  Spatial frequency is surprisingly important to our visual system – lots of basic features of the visual world, like orientation or motion, are processed first according to which spatial frequency the information is available at.

Spatial frequency is behind the Einstein-Marilyn illusion, whereby you see Albert Einstein if the image is large or close up, and Marilyn Monroe if the image is small / seen from a distance (try it! You’ll have to walk away from your screen to see it change).

The Einstein Monroe was created by Dr. Aude Oliva at MIT for the March 31st 2007 issue of New Scientist magazine

Depending on distance, different spatial frequencies are easier to see, and if those spatial frequencies encode different information then you can make a hybrid image which switches as you alter your distance from it.

Spatial frequency is also why, when you’re flying over the ocean, you can see waves which appear not to move. Although you vision is sensitive enough to see the wave, the motion sensitive part of your visual system isn’t as good at the fine spatial frequencies – which creates a natural illusion of static waves.

The contrast sensitivity image at the head of this post varies contrast top to bottom (low to high) and spatial frequency left to right (low to high). The point at which the bars stop looking distinct picks out a ridge which rises (to a maximum at about about 10 cycles per degrees of angle) and then drops off. Where this ridge is will vary depending on your particular visual system and what distance you view the image at. It is the ultimate individualised data visualisation – it picks out the particular sensitivity of your own visual system, in real time. It’s even interactive, instantly adjusting for momentary changes in parameters like brightness!

More on hybrid images (including some neat examples): Oliva, A., Torralba, A., & Schyns, P. G. (2006, July). Hybrid images. In ACM Transactions on Graphics (TOG) (Vol. 25, No. 3, pp. 527-532). ACM.

More on the visual system, including the contrast sensitivity function: Frisby, J. P., & Stone, J. V. (2010). Seeing: The computational approach to biological vision. The MIT Press.

How To Become A Centaur

Nicky Case (of Explorable Explanations and Parable of the Polygons internet fame) has a fantastic essay which picks up on the theme of my last Cyberselves post – technology as companion, not competitor.

In How To Become A Centaur Case gives blitz history of AI, and of its lesser known cousin IA – Intelligence Augmentation. The insight that digital technology could be a a ‘bicycle for the mind’ (Steve Jobs’ quote) gave us the modern computer, as shown in the 1968 Mother of All Demos which introduced the world to the mouse, hypertext, video conferencing and collaborative working. (1968 people! 1968! As Case notes, 44 years before google docs, 35 years before skype).

We’re living in the world made possible by Englebart’s demo. Digital tools, from mere phones to the remote presence they enable, or the remote action that robots are surely going to make more common, and as Case says:

a tool doesn’t “just” make something easier — it allows for new, previously-impossible ways of thinking, of living, of being.

And the vital insight is that the future will rely on identifying the strengths and weakness of natural and artificial cognition, and figuring out how to harness them together. Case again:

When you create a Human+AI team, the hard part isn’t the “AI”. It isn’t even the “Human”.

It’s the “+”.

The article is too good to try to summarise. Read the full text here

Cross-posted at the Cyberselves blog.

Previously: Tools, substitutes or companions: three metaphors for thinking about technology, Cyberselves: How Immersive Technologies Will Impact Our Future Selves

Debating Sex Differences: Talk transcript

A talk I gave titled “Debating Sex Differences in Cognition: We Can Do Better” now has a home on the web.

The pages align a rough transcript of the talk with the slides, for your browsing pleasure. readers will recognise many of the slides, which started their lives as blog posts. The full series is linked from this first post: Gender brain blogging. The whole thing came about because I was teaching a graduate discussion class on Cordelia Fine’s book, and then Andrew over at psychsciencenotes invited me to give a talk about it.

Here’s a bit from the introduction:

I love Fine’s book. I think of it as a sort of Bad Science but for sex differences research. Part of my argument in this talk is that Fine’s book, and reactions to it, can show us something important about how psychology is conducted and interpreted. The book has flaws, and some people hate it, and those things too are part of the story about the state of psychological research.

More here