Do “Growth Mindset” interventions improve students’ academic attainment?

“We conducted a systematic review and multiple meta-analyses of the growth mindset intervention literature. Our goal was to answer two questions: (a) Do growth mindset interventions generally improve students’ academic achievement? and (b) Are growth mindset intervention effects due to instilling growth mindsets in students or are apparent effects due to shortcomings in study designs, analyses, and reporting? To answer these questions, we systematically reviewed the literature and conducted multiple meta-analyses imposing varying degrees of quality control. Our results indicated that apparent effects of growth mindset interventions are possibly due to inadequate study designs, reporting flaws, and bias. In particular, the systematic review yielded several concerning patterns of threats to internal validity.”

Here’s a pic:

Can you bullshit a bullshitter?

You can bullshit a bullshitter, except if they also have high cognitive ability, according to Littrell et al. (2021).

Littrell, S., Risko, E. F., & Fugelsang, J. A. (2021). ‘You can’t bullshit a bullshitter’ (or can you?): Bullshitting frequency predicts receptivity to various types of misleading information. British Journal of Social Psychology, 60(4), 1484–1505.

No reasoning task is too irritating to be completed

Consider the sentence: “No head injury is too trivial to be ignored.” What does it mean?

Now consider: “No missile is too small to be banned.”

Go back to the first sentence – are you sure it means what you thought it did?

See Wason, P. C., & Reich, S. S. (1979). A Verbal Illusion. Quarterly Journal of Experimental Psychology, 31(4), 591–597.

Formal education and training

“[…] formal education and training rarely enhances competence. Instead, the so-called educational system mainly performs sociological functions, like controlling access to protected occupations and legitimising huge disparities in quality of life. These, in turn, have the effect of compelling most people, against their better judgement, to participate in the unethical activities of which modern society is so largely composed – the manufacture and marketing of junk foods, junk toys, junk education and junk research.”

– John Raven (2003, p. 360)


John, R. (2003). CPD – What should we be developing? The Psychologist, 16(7), 360–362.


People are rightly critical of the Myers–Briggs Type Indicator (MBTI). But some of the types are moderately correlated with the Big Five dimensions, which are seen as more credible in differential psychology. MBTI extraversion correlates with… wait for it… Big Five extraversion (50% shared variance). MBTI intuition correlates with openness to new experiences (40% shared variance). The opposite poles correlate as you’d expect.

Here are the key correlations (Furnham et al., 2003, p. 580, gender and linear effects of age have been partialed out):

“Neuroticism was most highly correlated with MBTI Extraversion (r = -.30, p = .001) and Introversion (r = .31, p < .001). Costa and McCrae’s Extraversion was most highly correlated with Myers-Briggs Extraversion (r = .71, p < .001) and Introversion (r=-.72, p < .001). Openness was most highly correlated with Sensing (r = -.66, p < .001) and Intuition (r = .64, p < .001). Agreeableness was most highly correlated with Thinking (r=-41, p < .001) and Feeling (r = .28, p < .001). Conscientiousness was most highly correlated with Judgment (r = .46, p<.001) and Perception (r=-.46, p < .001).”

Dichotomising is still silly, particularly for scores close to thresholds, where a light breeze might flip someone’s type from, say, I to E or vice verse. But the same can be said of any discretisation taken too seriously. Consider also clinical bands on mental health questionnaires and attachment styles on the Experience in Close Relationships Scale.

Also silly are tautologous non-explanations of the form: they behave that way because they’re E. Someone is E because they ticked a bunch of boxes saying they consider themselves extraverted! The types are defined transparently in terms of thoughts, feelings, and behaviour. They help structure self-report, but don’t explain why people are the way they are. Explanations require mechanisms.


Furnham, A., Moutafi, J., & Crump, J. (2003). The relationship between the revised NEO-Personality Inventory and the Myers-Briggs Type Indicator. Social Behavior and Personality, 31, 577–584.

Emotional blunting cured by reading original research

“Antidepressants can cause ‘emotional blunting’, study shows”, said the Grauniad today. The study by Langley et al. (2023) randomised 66 healthy participants (i.e., not requiring antidepressants) to either SSRI (20 mg of escitalopram – a high dose) or placebo, daily for 21 days.

I have two brief observations:

Almost all the statistical analyses were classical, with 95% confidence intervals including zero interpreted as not statistically significant. The authors’ headline-grabbing finding, concerning reinforcement sensitivity, was for one of four outcomes modelled using hierarchical Bayesian modelling. A 90% highest density interval excluded zero. However, the 95% interval included zero, so following the conventions of the rest of the paper would be counted as a null effect. There was no comment on this in the paper, which strikes me as a little odd, particularly given the large number of preregistered study outcome measures (16 primary, 44 secondary, 32 other) and consequent risk of a false positive.

Additionally, the headlines and study’s conclusion claim that their findings may explain the emotional blunting sometimes reported by users of SSRIs. But I don’t see how emotional blunting relates to the probabilistic reversal learning task the authors used.

I hope the study receives critical scrutiny in the press.


Langley, C., Armand, S., Luo, Q. et al. Chronic escitalopram in healthy volunteers has specific effects on reinforcement sensitivity: a double-blind, placebo-controlled semi-randomised studyNeuropsychopharmacol. (2023).

Overrated: The predictive power of attachment (2016)

“The fact is that there’s no strong evidence for parent–child attachment in infancy predicting anything much about children’s later development. Indeed, Booth-LaForce and Roisman’s definitive 2014 study showed that early attachment doesn’t even predict attachment later in development, let alone all of these other things.”

Nice, concise, critical analysis of attachment claims, by Elizabeth Meins (2016).

Wink wink

Two interesting papers.

  1. How Focusing on Individual-Level Solutions Has Led Behavioral Public Policy Astray (Chater & Loewenstein, 2022)

    “An influential line of thinking in behavioral science, to which the two authors have long subscribed, is that many of society’s most pressing problems can be addressed cheaply and effectively at the level of the individual, without modifying the system in which individuals operate. Along with, we suspect, many colleagues in both academic and policy communities, we now believe this was a mistake. Results from such interventions have been disappointingly modest. But more importantly, they have guided many (though by no means all) behavioral scientists to frame policy problems in individual, not systemic, terms…”

  2. No evidence for nudging after adjusting for publication bias (Maier, et al., 2022)

    ‘Thaler and Sunstein’s “nudge” (1) has spawned a revolution in behavioral science research. Despite its popularity, the “nudge approach” has been criticized for having a “limited evidence base” (e.g., ref. 2). Mertens et al. (3) seek to address that limitation with a timely and comprehensive metaanalysis. Mertens et al.’s headline finding is that “choice architecture [nudging] is an effective and widely applicable behavior change tool” (p. 8). We propose their finding of “moderate publication bias” (p. 1) is the real headline; when this publication bias is appropriately corrected for, no evidence for the effectiveness of nudges remains…’

On a relevance criterion

Logicians study logics – plural. There are different logics for different reasoning tasks. Classical logic, the flavour taught to undergraduate students of all persuasions, falls apart when confronted with the kinds of reasoning that people do effortlessly every day. My favourite way to break classical logic involves an innocent “if” and “or”.

Ponder the following sentence (based on an example by Alf Ross, 1944):

If Alex posted the letter [P], then Alex posted the letter [P] or Alex set fire to the letter [F].

If you think this sentence is true, then your interpretation and reasoning are compatible with translating it into classical logic using the material conditional (\(\Rightarrow\)) for the “if” and inclusive disjunction (\(\lor\)) for the “or”. You could write it like this and it’s trivially true: \(P \Rightarrow (P \lor F)\).

Some people are perfectly content with this interpretation, but many think the sentence is fishy and false.  There are a number of ways to explain what has happened.

One is to assume that the issue is language pragmatics rather than logic. Pragmatics studies the ways in which context and social conventions for communication affect people’s interpretation of language. According to one theory of communication (see Liza Verhoeven’s 2007 explanation), asserting that you posted the letter or burned it under the assumption that you posted it violates principles of cooperativeness. These principles affect the meaning of a sentence and its truth, so in this case the sentence is false.

Another way to make sense of what has gone wrong is using a relevance criterion devised by Gerhard Schurz (1991). The first step we need to take is to transform the “if” into an argument with a single premise and conclusion.

Premise: Alex posted the letter [P].
Conclusion: Alex posted the letter [P] or Alex set fire to the letter [F].

This is an uncontroversial step in classical logic, e.g., application of a rule for introducing an “if” in natural deduction.

Schurz introduces a criterion for a conclusion relevance that roughly goes as follows. The starting point is an argument that is valid according to classical logic. That’s the case for the argument above. If there are any terms in the conclusion that can be substituted with arbitrary alternatives without affecting the argument’s validity, then the conclusion is irrelevant. Otherwise the conclusion is relevant.

For our letter example, we can replace “Alex set fire to the letter” with anything and it has no effect on the validity of the argument. Alex opened the letter. Alex scribbled on the letter. Alex swallowed the letter. The letter was a surrealist painting. The letter was the size of house. And so on. No substitution in the second half of the conclusion can affect the validity of the argument, so the conclusion is irrelevant.

How about an argument where the conclusion is relevant? The trick is to ensure that everything in the conclusion is… relevant. That’s what I like about the criterion: it formalises (and the details are fiddly) an intuitive property of arguments. Here’s an easy example:

Premise: It’s raining and I left my umbrella at home
Conclusion: I left my umbrella at home and it’s raining

This is an example of the conjunction, “and”, being commutative in classical logic: the order of the conjuncts in the sentence (the parts on either side of “and”) doesn’t affect its truth. There are many ways to edit the conclusion so that the argument is no longer valid. For instance replace one or both of the conjuncts with “I posted a letter”. Then the conclusion doesn’t follow from the premise since the premise doesn’t tell us anything about a letter.

Colleagues and I explored people’s interpretations of these kinds of sentence about a decade ago in the context of an alleged paradigm shift in the psychology of reasoning. Read all about it. I was reminded of this again as Google Scholar dutifully notified me that Michał Sikorski recently cited it (thank you kindy Michał!).

A psychoanalyst walks into a bar(red subject)

A psychoanalyst walks into a bar with a book on logic and set theory. He orders a whisky. And another. Twelve hours and a lock-in later, all he has to show for the evening is a throbbing headache and some indecipherable rubbish scrawled on a napkin.

That’s the only conceivable explanation for these diagrams from The Subversion of the Subject and the Dialectic of Desire in the Freudian Unconscious, by Jacques Lacan (published in the Écrits collection):

But, surely this notation means something? After all, Lacan is famous and academics across the world dedicate their lives to understanding his genius.

Also the notation f(x) is a function, f, applied to argument x – that’s recognisable from maths. So the I(A) and s(A) must mean something…?

To illustrate how function notation is usually used, consider the Fibonacci sequence, which pops up in all kinds of interesting places in nature. It is defined as follows:

f(0) = 0,
f(1) = 1,
f(n) = f(n-1) + f(n-2), for n > 1.

In English, this says that the first two numbers in the sequence are 0 and 1 and the numbers following are obtained by summing the previous two. So the sequence goes: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, …

The function notation “does something”. It provides a way of defining and referring to (here, mathematical) concepts. I claim that the brief explanation above would make some kind of sense to most people who can add two numbers together.

Less well-known, but appearing in university philosophy courses, is the lozenge symbol, ◊, which means “possible” in a particular kind of logic called modal logic. So if R stands for “it’s raining” then ◊R stands for “it’s possible that it’s raining”. It seems plausible that there is something meaningful here in Lacan’s use of the symbol too.

Here is Lacan, “explaining” his notation to his almost entirely non-mathematical readership:


Lacan doesn’t try to explain what the notation means; he doesn’t seem to want readers to understand. Maybe he is just too clever and if only we persevered we would get what he means. Elsewhere in the same text, Lacan uses arithmetic to argue that “the erectile organ can be equated with \(\sqrt{-1}\)”. I’m told this is a joke because \(\sqrt{-1}\) is an imaginary number. Maybe trainee psychoanalysts learn about complex numbers so get the joke. I doubt it though. Maybe all Lacanian discourse is dadaist performance – that at least would make some sense.

Alan Sokal and Jean Bricmont have written a book-length critique of Lacan’s maths and others’ similar misuse of natural science concepts. Having read lots of mathematical texts and seen how authors make an effort to introduce their notation, I think it’s entirely possible Lacan is a fraud, ◊(Lacan is a fraud). That might sound harsh, but forget how famous he is and just look at the pretentious rubbish he writes.