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The Many Ways our Memory Fails Us (Part 3)

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In the first two parts of our series on memory, we covered four major “sins” committed by our memories: Absent-Mindedness, Transience, Misattribution, and Blocking, using Daniel Schacter’s The Seven Sins of Memory as our guide.

We’re going to finish it off today with three other sins: Suggestibility, Bias, and Persistence, hopefully leaving us with a full understanding of our memory and where it fails us from time to time.



As its name suggests, the sin of suggestibility refers to our brain’s tendency to misremember the source of memories:

Suggestibility in memory refers to an individual’s tendency to incorporate misleading information from external sources — other people, written materials or pictures, even the media — into personal recollections. Suggestibility is closely related to misattribution in the sense that the conversion of suggestions into inaccurate memories must involve misattribution. However, misattribution often occurs in the absence of overt suggestion, making suggestibility a distinct sin of memory.

Suggestibility is such a difficult phenomenon because the memories we’ve pulled from outside sources seem as truly real as our own. Take the case of a “false veteran” which Schacter describes in the book:

On May 31, 2000, a front-page story in the New York Times described the baffling case of Edward Daly, a Korean War veteran who made up elaborate — but imaginary — stories about his battle exploits, including his involvement in a terrible massacre in which he had not actually participated. While weaving his delusional tale, Daly talked to veterans who had participated in the massacre and “reminded” them of his heroic deeds. His suggestions infiltrated their memories. “I know that Daly was there,” pleaded one veteran. “I know that. I know that.”

The key word here is infiltrated. This brings to mind the wonderful Christopher Nolan movie Inception, about a group of experts who seek to infiltrate the minds of sleeping targets in order to change their memories. The movie is fictional but there is a subtle reality to the idea: With enough work, an idea that is merely suggested to us in one context can seem like our own idea or our own memory.

Take suggestive questioning, a problem with criminal investigations. The investigator talks to an eyewitness and, hoping to jog their memory, asks a series of leading questions, arriving at the answer he was hoping for. But is it genuine? Not always.

Schacter describes a psychology experiment wherein participants see a video of a robbery and then are fed misleading suggestions about the robbery soon after, such as the idea that the victim of the robbery was wearing a white apron. Amazingly, even when people could recognize that the apron idea was merely suggested to them, many people still regurgitated the suggested idea!

Previous experiments had shown that suggestive questions produce memory distortion by creating source memory problems like those in the previous chapter: participants misattribute information presented only in suggestive questions about the original videotape. [The psychologist Philip] Higham’s results provide an additional twist. He found that when people took a memory test just minutes after receiving the misleading question, and thus still correctly recalled that the “white apron” was suggested by the experimenter, they sometimes insisted nevertheless that the attendant wore a white apron in the video itself. In fact, they made this mistake just as often as people who took the memory test two days after receiving misleading suggestions, and who had more time to forget that the white apron was merely suggested. The findings testify to the power of misleading suggestions: they can create false memories of an event even when people recall that the misinformation was suggested.

The problem of overconfidence also plays a role in suggestion and memory errors. Take an experiment where subjects are shown a man entering a department store and then told he murdered a security guard. After being shown a photo lineup (which did not contain the gunman), some were told they chose correctly and some were told they chose incorrectly. Guess which group was more confident and trustful of their memories afterwards?

It was, of course, the group that received reinforcement. Not only were they more confident, but they felt they had better command of the details of the gunman’s appearance, even though they were as wrong as the group that received no positive feedback. This has vast practical applications. (Consider a jury taking into account the testimony of a very confident eyewitness, reinforced by police with an agenda.)


One more interesting idea in reference to suggestibility: Like the DiCaprio-led clan in the movie Inception, psychologists have been able to successfully “implant” false memories of childhood in many subjects based merely on suggestion alone. This should make you think carefully about what you think you remember about the distant past:

[The psychologist Ira] Hyman asked college students about various childhood experiences that, according to their parents, had actually happened, and also asked about a false event that, their parents confirmed, had never happened. For instance, students were asked: “When you were five you were at the wedding reception of some friends of the family and you were running around with some other kids, when you bumped into the table and spilled the punch bowl on the parents of the bride.” Participants accurately remembered almost all of the true events, but initially reported no memory of the false events.

However, approximately 20 to 40 percent of participants in different experimental conditions eventually came to describe some memory of the false event in later interviews. In one experiment, more than half of the participants who produced false memories describe them as “clear” recollections that included specific details of the central even, such as remembering exactly where or how one spilled the punch. Just under half reported “partial” false memories, which included some details but no specific memory of the central event.

Thus is the “power of the suggestion.”

The Sin of Bias

The problem of bias will be familiar to regular readers. In some form or another, we’re subject to mental biases every single day, most of which are benign, some of which are harmful, and most of which are not hard to understand. Biases specific to memory are so good to study because they’re so easy and natural to fall into. Because we trust our memory so deeply, they often go unquestioned. But we might want to be careful:

The sin of bias refers to distorting influences of our present knowledge, beliefs, feelings on new experiences, or our later memories of them. In the stifling psychological climate of 1984, the Ministry of Truth used memory as a pawn in the service of party rule. Much in the same manner, biases in remembering past experiences reveal how memory can serve as a pawn for the ruling masters of our cognitive systems.

There are four biases we’re subject to in this realm: Consistency and change bias, hindsight bias, egocentric bias, and stereotyping bias.

Consistency and Change Bias

The first is a consistency bias: We re-write our memories of the past based on how we feel in the present. In one experiment after another, this has undoubtedly been proven true. It’s probably something of a coping mechanism: If we saw the past with complete accuracy, we might not be such happy individuals.

We re-write our memories of the past based on how we feel in the present. Click To Tweet

We often re-write the past so that it seems we’ve always felt like we feel now, that we always believed what we believe now:

This consistency bias has turned up in several different contexts. Recalling past experiences of pain, for instance, is powerfully influenced by current pain level. When patients afflicted by chronic pain are experiencing high levels of pain in the present, they are biased to recall similarly high levels of pain in the past; when present pain isn’t so bad, past pain experiences seem more benign, too. Attitudes towards political and social issues also reflect consistency bias. People whose views on political issues have changed over time often recall incorrectly past attitudes as highly similar to present ones. In fact, memories of past political views are sometimes more closely related to present views than what they actually believed in the past.

Think about your stance five or ten years ago on some major issue like sentencing for drug-related crime. Can your recall specifically what you believed? For most people, they believe they have stayed consistent on the issue. But easily performed experiments show that a large percentage of people who think “all is the same” have actually changed their tune significantly over time. Such is the bias towards consistency.

This affects relationships fairly significantly: Schacter shows that our current feelings about our partner color our memories of our past feelings.

Consider a study that followed nearly four hundred Michigan couples through the first years of their marriage. In those couples who expressed growing unhappiness over the four years of the study, men mistakenly recalled the beginnings of their marriages as negative even though they said they were happy at the time. “Such biases can lead to a dangerous “downward spiral,” noted the researchers who conducted the study. “The worse your current view of your partner is, the worse your memories are, which only further confirms your negative attitudes.”

In other contexts, we sometimes lean in the other direction: We think things have changed more than they really have. We think the past was much better than it is today, or much worse than it is today.

Schacter discusses a twenty-year study done with a group of women between 1969 and 1989, assessing how they felt about their marriages throughout. Turns out, their recollections of the past were constantly on the move, but the false recollection did seem to serve a purpose: Keeping the marriage alive.

When reflecting back on the first ten years of their marriages, wives showed a change bias: They remembered their initial assessments as worse than they actually were. The bias made their present feelings seem an improvement by comparison, even though the wives actually felt more negatively ten years into the marriage than they had at the beginning. When they had been married for twenty years and reflected back on their second ten years of marriage, the women now showed a consistency bias: they mistakenly recalled that feelings from ten years earlier were similar to their present ones. In reality, however, they felt more negatively after twenty years of marriage than after ten. Both types of bias helped women cope with their marriages. 

The purpose of all this is to reduce our cognitive dissonance: That mental discomfort we get when we have conflicting ideas. (“I need to stay married” / “My marriage isn’t working” for example.)

Hindsight Bias

We won’t go into hindsight bias too extensively, because we have covered it before and the idea is familiar to most. Simply put, once we know the outcome of an event, our memory of the past is forever altered. As with consistency bias, we use the lens of the present to see the past. It’s the idea that we “knew it all along” — when we really didn’t.

A large part of hindsight bias has to do with the narrative fallacy and our own natural wiring in favor of causality. We really like to know why things happen, and when given a clear causal link in the present (Say, we hear our neighbor shot his wife because she cheated on him), the lens of hindsight does the rest (I always knew he was a bad guy!). In the process, we forget that we must not have thought he was such a bad guy, since we let him babysit our kids every weekend. That is hindsight bias. We’re all subject to it unless we start examining our past with more detail or keeping a written record.

Egocentric bias

The egocentric bias is our tendency to see the past in such a way that we, the rememberer, look better than we really are or really should. We are not neutral observers of our own past, we are instead highly biased and motivated to see ourselves in a certain light.

The self’s preeminent role in encoding and retrieval, combined with a powerful tendency for people to view themselves positively, creates fertile ground of memory biases that allow people to remember past experiences in a self-enhancing light. Consider, for example, college students who were led to believe that introversion is a desirable personality trait that predicts academic success, and then searched their memories for incidents in which they behaved in an introverted or extroverted manner. Compared with students who were led to believe that extroversion is a desirable trait, the introvert-success students more quickly generated memories in which they behaved like introverts than like extroverts. The memory search was biased by a desire to see the self positively, which led students to select past incidents containing the desired trait.

The egocentric bias occurs constantly and in almost any situation where it possibly can: It’s similar to what’s been called overconfidence in other arenas. We want to see ourselves in a positive light, and so we do. We mine our brain for evidence of our excellent qualities. We have positive maintaining illusions that keep our spirits up.

This is generally a good thing for our self-esteem, but as any divorced couple knows, it can also cause us to have a very skewed version of the past.

Bias from Stereotyping

In our series on the development of human personality, we discussed the idea of stereotyping as something human beings do constantly and automatically; the much-maligned concept is central to how we comprehend the world.

Stereotyping exists because it saves energy and space — it allows us to consolidate much of what we learn into categories with broadly accurate descriptions. As we learn new things, we either slot them into existing categories, create new categories, or slightly modify old categories (the one we like the least, because it requires the most work). This is no great insight.

But what is interesting is the degree to which stereotyping colors our memories themselves:

If I tell you that Julian, an artist, is creative, temperamental, generous, and fearless, you are more likely to recall the first two attributes, which fit the stereotype of an artist, than the latter two attributes, which do not. If I tell you that he is a skinhead, and list some of his characteristics, you’re more likely to remember that he is rebellious and aggressive than that he is lucky and modest. This congruity bias is especially likely to occur when people hold strong stereotypes about a particular group. A person with strong racial prejudices, for example, would be more likely to remember stereotypical features of an African American’s behavior than a less prejudiced person, and less likely to remember behaviors that don’t fit the stereotype.

Not only that, but when things happen which contradict our expectations, we are capable of distorting the past in such a way to make it come in line. When we try to remember a tale after we know how it ends, we’re more likely to distort the details of the story in such a way that the whole thing makes sense and fits our understanding of the world. This is related to the narrative fallacy and hindsight bias discussed above.


The final sin which Schacter discusses in his book is Persistence, the often difficult reality that some memories, especially negative ones, persist a lot longer than we wish. We’re not going to cover it here, but suggest you check out the book in its entirety to get the scoop.

And with that, we’re going to wrap up our series on the human memory. Take what you’ve learned, digest it, and then keep pushing deeper in your quest to understand human nature and the world around you.