Implicit Revolution 1: How We Develop Implicit Bias


40 years ago, researchers found that patients with amnesia could form new memories… implicitly. This sparked an ongoing revolution in research on the hidden mind.


NARRATOR: We’re starting today’s podcast by talking about amnesia. Ask anyone what it means, and you’ll hear the same basic definition: the loss of memory.

Sometimes, the memories are old: things like who you are or what elementary school you went to. Sometimes, the memories are newer: what just happened? Who did you meet yesterday?

But the overall concept is the same: the things, people, and events you have amnesia for, you can no longer remember. But that’s not the whole story.

Around the turn of the 20th century, a peculiar report¬ was published: the Swiss neurologist Édouard Claparède wrote of hiding a small threading needle between his fingers and pricking the woman he shook hands with. The next day, he tried to shake her hand again, but this time she quickly pulled away.

Now, her reaction makes perfect sense… except for the fact that she had Korsakoff’s syndrome: a type of amnesia that kept her from forming new memories.

This woman had no idea what had happened the day before. She didn’t even recognize Claparéde, a man she saw every day. But some part of her mind – and this was a part that was hidden even from her – remembered what he had done.

Now, this was a different kind of memory than what we normally think of. It’s a memory that exists outside of conscious awareness. And amnesia or not, we all have it. So what exactly is it? How does our mind learn; what does it store? Perhaps more importantly, how does it shape our behavior? Today’s podcast is the first in a two-part series on the implicit revolution. Welcome to Outsmarting Human Minds.

MAHZARIN BANAJI: So think about this. If I ask you, “what did you eat for breakfast today?” Or if I say to you: “Remember when you were in fifth grade and you got lost?” and you have to remember that…

NARRATOR: This is Harvard psychologist Mahzarin Banaji.

MAHZARIN BANAJI: In any such act of remembering, you consciously go into your mind, and you try to pull something out, whether it was from a few hours ago or days ago or years ago. That kind of memory is a very conscious kind of memory. And the interesting result was that the people who were amnesiac patients, even though they had no conscious memory, they did seem to have some lingering sense of what had happened.

So in the experiment…

NARRATOR: This is a 1984 study conducted by Graf, Squire, and Mandler.

MAHZARIN BANAJI: …you could give them a list of words to learn, and say one of those words happened to be the word “motel”. M-O-T-E-L. Later you would say to them, you know, “Give me a word that starts with M-O-T.” Now, they could pick dozens of words.

NARRATOR: I tried this and pretty quickly came up with “motor”, “mother”, “motivate”, and “motion”.

MAHZARIN BANAJI: And yet they would be much more likely to generate “motel,” even though they had no recollection that they had even learned the word “motel” the day before. Something got saved in memory, and it came out when they were asked, even though they had no clue. That form of memory is what we call implicit memory.

NARRATOR: By the 1980s, the data was undeniable. These patients with amnesia – people who couldn’t tell you what they had eaten for breakfast or recognize the doctor they saw every day – they were remembering things. Not in a way that they could put into words, or even know that it was happening. But they were getting better at doing certain things with practice, even if they thought each time was the first time they were trying it. They were choosing words that they had learned in a previous task, even if they didn’t remember learning that word.

What’s more, the research was showing that what we were seeing in patients with amnesia was also happening in everyone!

MAHZARIN BANAJI: You know, we think we’re so different from amnesiac patients. And we are; there is no question that we have more intact memories compared to them. The real question is: are we a little bit like amnesiac patients? Do we also have information that’s stored in our minds that’s there, that’s used, but that we don’t consciously remember? I mean there’s so many examples we might have in everyday life of this…

NARRATOR: Like when you see a face and you feel like you’ve seen them before – what is that? And then you don’t know if you’ve met them or what.

MAHZARIN BANAJI: You can’t tell what the source of that familiarity is. And that’s indeed exactly what Larry Jacoby capitalized on when he did these lovely experiments showing that you can take a name like Sebastian Weisdorf, some Joe Schmoe, and turn him into a famous person simply by exposing people to the name ‘Sebastian Weisdorf’ on day 1, and then later giving them a long list of names and asking them to identify the famous people on the list. Well, there were some real famous people there! You know, ex-presidents and athletes and movie stars. But the interesting question was: will they mistakenly identify Sebastian Weisdorf as famous, and he found indeed they did at a level much higher than they would have if they not seen the name the day before. You see the name Sebastian Weisdorf and it looks familiar. Why? It could be because that I saw name before, it could be because he’s a Canadian hockey player, who knows? That’s an example of all of us, ordinary human beings, with supposedly intact memories, also showing an effect that’s very similar.

NARRATOR: Another study by Tory Higgins and colleagues found that these implicit connections can influence how much we like another person: whether we find them to be adventurous rather than reckless; self-confident rather than conceited. This research showed that our impression of a person can be swayed by something we have no clue about.

All this tells us: we don’t know our minds.

MAHZARIN BANAJI: If you said to me, “Mahzarin, do you know what your pancreas is doing right now?” I would say, “I have no clue. Where is my pancreas really?”

But if you said to me, “Mahzarin, do you know what your mind is doing now?”, I’d say “sure! I know exactly what it’s doing. I know my mind. I can sense it, as it has thoughts and feelings.” But the point I want to make today is that there are significant parts of our minds that lie beyond the reach of conscious awareness. Those parts do exist. And they affect the things that we think and do. We just don’t know that’s what they’re doing.

NARRATOR: And that brings us to the second question of this podcast, which is: how? How are we all walking around, making these connections and memories without meaning to, or even being aware that we’re doing it?

Mahzarin tells me: it’s all about our experience.

MAHZARIN BANAJI: Let’s talk about a simple thing called “mental association”. Rats, chimpanzees, humans, we all have a fundamental ability to learn how to pair things that happen together in time and space.

Mother and father, bread and butter, salt and pepper, day and night. Sometimes they’re opposites, sometimes they’re just related. But thinking of the one will remind us of the other because the two have co-occurred over and over again in our experience.

NARRATOR: That’s it. It’s just experience. Listen to the same playlist again and again, and eventually when one song ends, you’ll immediately start hearing the next song in your mind. You’re not trying to make this connection – you just do.

That’s how powerful our minds are. Of course, the trouble with learning is that we can’t pick and choose what associations we make. They’re simply the thumbprint that culture and experience have left on our brains. Much like how Pavlov’s dogs couldn’t help the fact that their mouths startrf watering as soon as they heard the bell, we can’t help but respond to the implicit associations we’ve picked up throughout life.

So while our implicit memories allow us to do things like drive a car, tie our shoes, get back home after work effortlessly, we also have to ask: what else have we learned? What have we learned about people who are a different height, race, or sexuality? What gets activated when we hear an accent or see someone in a wheelchair? And then, there’s the bigger, looming question: what happens when the associations we’ve implicitly learned run counter to the things we consciously believe?

MAHZARIN BANAJI: We humans are unique in the animal kingdom in that we not only have a deep sense of morality, we have codified it in our mottos, credos, and most importantly in our laws.

And at the best of times, we do act in accordance with our values and beliefs. We try to do the right thing. But there are also times when our decisions are influenced not by what we believe, but by what we have learned. And that’s where we see disparities.

NARRATOR: Consider healthcare for example: Dr. Monika Goyal and her colleagues looked at cases of appendicitis in the ER between 2003 and 2010, and they found that black children presenting with the same level of pain as white children were 80% less likely to receive opioid painkillers. Another study by Fowler and colleagues shows that older women receive fewer life-saving interventions than older men. Now, no doctor is going to say that these kinds of things are okay – but the data show that it’s happening. So we have to ask: what’s going on in the doctor’s mind at the moment of decision-making? Is something implicit shaping that decision?

And if so: how do we know?

Okay, so when I make a mistake, I try to catch it and fix it. But my question is, how do you catch something that you don’t know exists?

MAHZARIN BANAJI: You can’t. So the first step is to know what exists. You need a device.

NARRATOR: Almost a century after Claparède’s first report on amnesiac memory, mind scientists began creating these devices. These were tools, paradigms, tests that were all designed to reveal the kinds of associations that were getting stored in our minds, and how they influence our behavior. And in Part 2 of this podcast, we’ll explore one of these: the Implicit Association Test, and how psychologists Tony Greenwald, Mahzarin Banaji, and Brian Nosek harnessed the birth of the internet to share this device with the public.

Outsmarting Human Minds is a program founded by Mahzarin Banaji, devoted to improving decision-making using insights from psychological science. Support for Outsmarting Human Minds was provided by PwC and Harvard University. This episode was developed by Olivia Kang and Mahzarin Banaji. Sound editing and mixing was done by Evan Younger. Music was composed by Miracles of Modern Science. For references and related materials, go to


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“[W]here did this idea of implicit bias come from? How can we measure biases that people don’t know they have, or at least are unwilling to endorse openly?” Hear the conversation between psychologists Andy Lutrell and Mahzarin Banaji at Opinion Science.

“Is there a part of ourselves that we don’t acknowledge, that we don’t even have access to and that might make us ashamed if we encounter it?” NPR’s Invisibilia discusses the implicit revolution further in their episode “The Culture Inside”.


Claparède, E. (1951). Recognition and “me-ness” In D. Rapaport, Organization and pathology of thought: Selected sources (pp. 58-75). (Original French publication 1911).

Fowler, R.A., Sabur, N., Li, P., Juurlink, D. N, Pino, R., …, & Martin, C. M. (2007). Sex- and age-based differences in the delivery and outcomes of critical care. CMAJ, 177(12), 1513-1519.

Goyal, M. K., Kuppermann, N., & Cleary, S. D. (2015). Racial disparities in pain management of children with appendicitis in emergency departments. JAMA Pediatrics, 169(11), 996-1002.

Graf, P. Squire, L. R., & Mandler, G. (1984). The information that amnesic patients do not forget. Journal of Experimental Psychology: Learning, Memory, and Cognition, 10(1), 164-178.

Higgins, E. T., Rholes, W. S., & Jones, C. R. (1977). Category accessibility and impression formation. Journal of Experimental Social Psychology, 13, 141-154.

Jacoby, L. L., Kelley, C., Brown, J., & Jasechko, J. (1989). Becoming famous overnight: Limits on the ability to avoid unconscious influences of the past. Journal of Personality and Social Psychology, 56(3), 326-338.


The Implicit Revolution Part 1 was created and developed by Mahzarin Banaji and Olivia Kang with funding from PwC and Harvard University.

Narration by Olivia Kang, featuring Professor Mahzarin Banaji (Harvard University)

Sound Editing & Mixing by Evan Younger

Music by Miracles of Modern Science

Artwork by Olivia Kang