Science, Social Science

When Bad Ideas Refuse to Die: the Denial of Human Individuality

It is generally thought that science helps good ideas triumph over bad. The weight of evidence eventually pushes false claims aside.

But some ideas march onward despite the evidence against them. The discredited link between vaccines and autism continues to cause mischief and climate change skeptics continue to resurrect dead science.

Why, then, are some bad ideas so hard to kill?

A striking example of such a “zombie theory” comes from personality psychology. Personality psychologists study human individuality – how and why individuals differ in their patterns of behaviour and experience, and how those differences influence our lives.

For almost 50 years, an idea with a vexing immunity to evidence has needled this field. This idea is called situationism.

Is personality an illusion?

Introduced in the 1960s by American psychologist Walter Mischel, situationism is the idea is that human behaviour results only from the situation in which it occurs and not from the personality of the individual.

In his 1968 book Personality and Assessment, Mischel claimed that the whole concept of personality is untenable because people behave differently in different situations.

If there are no consistent patterns in our behaviour and we merely react, chameleon-like, to different contexts, then our sense of an enduring personality is illusory. With that bombshell, the person-situation debate erupted.

Situations versus personality

The notion that situations influence behaviour is patently true. Could we even imagine a world in which people did not adjust their behaviour to different contexts — from job interviews to romantic dinners?

Personality psychologists have shown time and again that the demands of situations shape and guide our behaviour. As one of the founders of personality psychology, Gordon Allport, observed in the 1930s:

We all know that individuals may be courteous, kind and generous in company or in business relations, and at the same time be rude, cruel and selfish at home.

But does this flexibility mean there is no consistency in behaviour, rendering the whole notion of personality untenable? Is there no tendency in some individuals to be consistently more courteous than others?

Here the empirical record disagrees. There is significant consistency of behavioural differences between people, both over time and across situations. These tendencies are well captured by measures of personality, as study after study has shown. This tells us that stable differences in personality are real and observable — they are not illusions.

As for the importance of personality, the evidence shows that personality traits are reliable predictors of many important life outcomes, from social behaviour to job performance, from educational achievement to health and well-being.

A case of consistency: the marshmallow study

Ironically, a particularly famous example of the stability and power of personality came from Mischel’s own research, which, as one report points out, drives him crazy.

In the marshmallow study, Mischel measured young children’s willpower by timing how long they could resist the temptation of a delicious treat. This simple test, it turns out, is a measure of the personality trait called conscientiousness. It also predicts the same outcomes later in life that conscientiousness does, including higher educational achievement and lower drug use. The facts that have emerged from this research are simply incompatible with situationism.

Laying situationism to rest

Even before it was disproven by the evidence, Mischel’s theory of situationism contained a logical non sequitur. Specifically, it assumed that a person’s behaviour can only be 100% consistent or else inconsistent — in which case there is no such thing as personality.

But why should the observation of changeable behaviour imply the absence of personality? By this reasoning, we should dismiss the whole notion of climate because weather is changeable.

By the 1990s, most personality psychologists considered situationism a dead duck. A prominent review of the literature concluded that the debate had, at last, fizzled out. The field was moving on and looking forward.

But the theory didn’t die.

Back from the dead

Time and again, the spectre of situationism has reappeared, causing a groaning sense of déjà vu for personality psychologists.

The theory has even spread beyond psychology, with a prominent behavioural economist recently claiming that Mischel’s “great contribution to psychology” was to show that there is “no such thing as a stable personality trait”.

Despite being buried by decades of research, situationism keeps kicking. According to one commentator, it “has morphed into something beyond the veracity of its arguments”. It has become an ideology.

In June this year, Mischel wheeled out situationism once again, this time on an episode of the NPR Invisibilia podcast titled The Personality Myth. Once again, we’re told “ultimately it’s the situation, not the person, that determines things.”

This baseless message drew sharp criticism on social media by several eminent personality psychologists.

As one observed:

[…] the contemporary research literature showing that personality traits exist, tend to be stable over time, and influence important life outcomes is never mentioned.

What gives life to bad ideas?

Why is situationism still being revived after decades of refutation? We suspect this can be explained by at least two factors.

The first is our all-too-human preference for lazy thinking. As Daniel Kahneman explains in Thinking Fast and Slow:

When faced with a difficult question, we often answer an easier one instead, usually without noticing the substitution.

In this case, the tricky question, “can our patterns of behaviour be generally stable yet highly changeable?”, is switched for a no-brainer, “is our behaviour perfectly consistent, or not?”

The second explanation may lie in the appeal of a surprising story. Some of the most alluring ideas in science — and to scientists — are those we find unexpected or counter-intuitive. And what could be more counter-intuitive than the thought that there may be nothing at all that makes you you?

The situationist idea that personality is an illusion is an arresting one, but it is false.

The Conversation

Luke Smillie is a Senior Lecturer in Psychology (Personality Psychology), University of Melbourne.

Nick Haslam is a Professor of Psychology, University of Melbourne

This article was originally published on The Conversation.


  1. rugby11 says

    Was thinking about this with the aids epidemic in South Africa with vitamins. How by the time they spoke openly about it we had a million infected people. Instead of 25 thousand.

  2. Yandoodan says

    I think you underestimate the power of ideology. When a scientific consensus conflicts with ideology, science goes out the door. In this case radical reductionists, who deny the existence of self or even consciousness, confront the scientific proof that personality exists, science loses. If you have a personality you have consciousness. If you can override your personality when events require it, you have the ability to choice and therefore “self”.

    You see the same thing over and over. Nuclear power’s safety is seen as conflicting with a deeply held belief that all complex technology harms Nature. Evolution (and sometimes geology) is seen as conflicting with the Bible’s authority. Climate change action, seen as calling for global energy use to be regulated by an unelected nomenclatura, is seen as conflicting with freedom and prosperity.

    • Yandoodan says

      Did I just write “ability to choice”? Gawd. When you edit computer text it’s amazing what slips through.

  3. Zado says

    I agree that science is being thrown out the door in favor of ideology, but I’m not sure it’s “radical reductionists” doing the throwing. Situationism, to me, seems to touch on the nature vs. nurture debate. Do we have a “nature,” a stable personality that depends on how our individual brains are wired? Or are our personal capacities totally malleable given the right situations and opportunities?

    In this debate there always have been and always will be people who detest the idea of individual human natures and who prefer to believe, against all evidence, that anyone can do anything and that genes play a minor role in determining personal characteristics. I believe these “dogmatic nurturists” (just made that up) are the ones keeping situationism alive, along with a few other bad ideas.

  4. Instead of whacking an idea or an ideology on the head screaming “it is not right, it is not true” it would be a much more fruitful approach to look at the data pro and con and if left undecided, search or create new data. Smillie and Haslam present their opinion, nothing more. I am not able to judge if their opinions are well informed on this particular subject but I sense thought policing here…they are saying that an idea is bad without actually telling us why it is bad and then they imply that bad ideas should not be brought up to discussion.

    What if you have new data that shows that the idea was not so bad after all, that it in fact gives useful thought tools in certain situations? Because some Smillies and Haslams have decided that the idea is bad, it should not be reconsidered?

    This smells a lot of what has been going on in the US humanist circles, especially in psychology and sociology. There is no intelligence, there is no race because WE say so and we have voted…

    No, I did not like this article. Thought policing is always a bad idea.

  5. frederick weimar says

    “Even in the best theory there’s a part that is false, and even in the worse theory there’s a part that is true”.

  6. Pingback: Outside in - Involvements with reality » Blog Archive » Chaos Patch (#124)

  7. A theory as to why people still cling to bad ideas such as “situationism”. They are the groundwork for modern political ideology. The “scientific proof” that is claimed here (namely, that personality exists) is insufficient to form a broader theory that can be used to prove that the human mind exists or even how the human mind works, because society has now favoured a completely reductionist view of personality and reductionism simply cannot explain our existence.

    This rationalism has serious political repercussions, because it makes a massive assertion about free will in that it claims to know what the human mind is, when it doesn’t. If we wish to think that humans are individuals in this “democracy” then we have to think that humans are also social and that socialisation and human culture has a massive impact on individual psychology. Therefore, it is not fair to cling to narrow conceptual frameworks like “situationism” or “personality type” when debating the philosophical issue of what the human mind is, which is what this article is doing in the first place. This fallacy about what scientific proof means is the reason why bad ideas are reproduced ceaselessly in psychology. And that’s a worse reason than the crap traditionalisms of universities or intellectual disciplines. Fallacies are rubbish and they need to be stopped so that we remain open to truth when it finally comes and know what to reason about in the meantime.

    Psychology as a discipline will always suffer from this fallacy of attaching larger assumptions to reductionist theories, because it refuses to engage with philosophy. It will therefore always be invalid. This fallacy renders psychology nothing more than a nonsensical debate about the human mind that actively obliterates any form of clear reasoning about what the human mind might actually be. The public have to be spoon-fed what to think of psychology, such as that personality psychology is as of yet unfortunately completely meaningless to human life because individuals cannot actually be reduced to a control group and this is simply insufficient to say that we have now proven that the human mind exists.

    I can’t understand why mind is not just simply an issue for philosophy and not for psychology (psychology is still just a hypothesis that refuses to admit it is even with neuroscience), but I suppose ideology hates philosophy (human thought). Reductionists don’t like this idea either, that human thought might actually exist and come from elsewhere somehow… Moral psychology answers these questions, but then normative ethics claims some kind of variation of the situationist approach and we’re back to where we started with reductionism. Perhaps we should just stop acting on faith and think more about the unconscious, or perhaps even consciousness, perhaps so we know what not to think of Marxism, maybe, if we wish to know what not to think of normativity!

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