Daniel Schacter’s “The Seven Sins of Memory”: Book Review, Notes + Analysis

Poor Ash’s Almanack > Book Reviews > Effective Thinking > psychology

Overall Rating: ★★★★★★ (6/7) (standout for its category)

Per-Hour Learning Potential / Utility: ★★★★★★ (6/7)

Readability: ★★★★★★ (6/7)

Challenge Level: 2/5 (Easy) | 206 pages ex-notes (288 official)

Blurb/Description: Harvard psychology chair Daniel Schacter categorizes failures of the human memory into seven categories, providing the best technical/fundamental overview of human memory I’ve found.

Summary: Even though this book is a bit dated (2002), it really holds up.  Schacter provides a detailed yet accessible overview of the various kinds of memory failures we can have and the (usually extremely limited) means we have of combating them.

Highlights: Schacter’s engaging and insightful book provides useful categorization and explanation, along with some interesting social insights – for example, that we’re generally forgiven for failures of retrospective memory (i.e. not being able to remember something from the past), but criticized / viewed as unreliable for failures of prospective memory (i.e., forgetting a lunch date).

Although he doesn’t go full Don Norman, he also does a good job of pointing out the futility of trying to use willpower or mnemonic techniques to improve our memory, suggesting we instead utilize structural problem solving (external reminders).

Lowlights: While 7SOM is the best technical/fundamental explanation of how and why our memories fail in predictable ways, I do think that most of the applications are covered by other books, such as Tavris/Aronson’s Mistakes were Made (but not by me) (MwM review + notes), Laurence Gonzales’s Deep Survival (DpSv review + notes), Don Norman’s The Design of Everyday Things (DOET review + notes), and Shawn Achor’s The Happiness Advantage (THA review + notes).

As such, while I really enjoy this book and got a lot out of it, I also think that if you’re planning to read the above books, much of 7SOM is covered and you don’t have to read it today (although you should read it sometime.)

There are a couple sections of the book that deal with tragic topics that are tough to stomach – i.e., mistaken eyewitness testimony, “suggested” memories, or forced false confessions that land innocent people in jail.  To be clear, there’s absolutely nothing wrong with the material or the way it’s written – I’m just saying that the first time I read the book, those parts were a little difficult for me to read on an emotional level.

Mental Model / ART Thinking Points:   recency bias,  memory,  overoptimismstructural problem solvinghindsight biassaliencemultitaskingloss aversionthe halo effectstorytelling,fundamental attribution error, consistency bias

You should buy a copy of The Seven Sins of Memory if: you have already read the aforementioned books (especially Mistakes were Made), and you want a thorough, engaging, insightful look at the fundamentals of human memory.

Reading Tips: None in particular.  It’s a compact, readable book.

Pairs Well With:

Tavris/Aronson’s Mistakes were Made (but not by me) (MwM review + notes).  A phenomenal deconstruction of how memory interacts with contrast biasincentiveslocal vs. global optimization, and other mental models to lead us to fail to recognize our own mistakes – despite clearly recognizing those of others.

Laurence Gonzales’s Deep Survival (DpSv review + notes).  While this isn’t directly about memory, it does go pretty extensively into how memory limitations interact with other models (like cognitionintuition / habit / stress) to help us live – or lead us to die – in life-or-death situations.

Don Norman’s The Design of Everyday Things (DOET review + notes).  This is my second-favorite book of all time; written from the perspective of someone who’s spent their career thinking deeply about how to design usable products (and systems), Norman makes it extremely clear how and why memory fails us – and how designers (of products or systems) can obviate those failures.

Shawn Achor’s The Happiness Advantage (THA review + notes).  Achor touches on memory in a few places, primarily by deconstructing why it is we can’t multitask.  (Gonzales makes similar points in Deep Survival.)


Reread Value: 3/5 (Medium)

More Detailed Notes + Analysis (SPOILERS BELOW):

IMPORTANT: the below commentary DOES NOT SUBSTITUTE for READING THE BOOK.  Full stop. This commentary is NOT a comprehensive summary of the lessons of the book, or intended to be comprehensive.  It was primarily created for my own personal reference.

Much of the below will be utterly incomprehensible if you have not read the book, or if you do not have the book on hand to reference.  Even if it was comprehensive, you would be depriving yourself of the vast majority of the learning opportunity by only reading the “Cliff Notes.”  Do so at your own peril.

I provide these notes and analysis for five use cases.  First, they may help you decide which books you should put on your shelf, based on a quick review of some of the ideas discussed.  

Second, as I discuss in the memory mental model, time-delayed re-encoding strengthens memory, and notes can also serve as a “cue” to enhance recall.  However, taking notes is a time consuming process that many busy students and professionals opt out of, so hopefully these notes can serve as a starting point to which you can append your own thoughts, marginalia, insights, etc.

Third, perhaps most importantly of all, I contextualize authors’ points with points from other books that either serve to strengthen, or weaken, the arguments made.  I also point out how specific examples tie in to specific mental models, which you are encouraged to read, thereby enriching your understanding and accelerating your learning.  Combining two and three, I recommend that you read these notes while the book’s still fresh in your mind – after a few days, perhaps.

Fourth, they will hopefully serve as a “discovery mechanism” for further related reading.

Fifth and finally, they will hopefully serve as an index for you to return to at a future point in time, to identify sections of the book worth rereading to help you better address current challenges and opportunities in your life – or to reinterpret and reimagine elements of the book in a light you didn’t see previously because you weren’t familiar with all the other models or books discussed in the third use case.

Schacter begins with some engaging anecdotes about memory failures, and introduces the outline of his book: a discussion of seven separate “sins” of memory:

transience, absent-mindedness, blocking, misattribution, suggestibility, bias, and persistence.”  

These can be aggregated into sinos of omission (failing to recall something) and commission (incorrect or unwanted memory).  While these sins may be annoying (or worse) in our lives, it helps to have some perspective: they’re features, not bugs; Schacter argues that:

“each of the seven sins is a by-product of otherwise desirable and adaptive features of the human mind.”  

In other words, trait adaptivity.

The first sin is “transience” – i.e. forgetting things over time – what is that person’s name?  What did I eat for lunch yesterday? What did I even come to this store to buy?  

In other words, trait adaptivity.

The first sin is “transience” – i.e. forgetting things over time – what is that person’s name?  What did I eat for lunch yesterday? What did I even come to this store to buy?

Schacter notes that a large number of studies seem to suggest a decay process: you forget the vast majority of information, very quickly (often within the course of a day or a few), and then the rate ofmemory loss slows down.  This is surprisingly similar to the forward-looking process of hyperbolic discounting, where we heavily discount the future but at some point stop discounting at all; i.e., something that happens in a year might as well happen in fifteen.  (Not literally, but directionally.)

Additionally, it seems like our memory works on some sort of representative “fill in the blank” process – we remember things that are part of the “daily script” but not things that don’t fit that (oddly, as this somewhat contradicts salience).  Additionally, we tend to remember the gist of things more than the specific details – i.e. that conference was fun rather than exactly who was there and what we talked about.

Unsurprisingly, memory worsens as we age – though perhaps not as much or as quickly as commonly imagined – it doesn’t seem to start until the 40s (for story recall) and the 50s (for lists of words), and even then, older groups generally recall only 10 – 15% less than younger groups.  Importantly, there is significant variability (hi, Charlie) – 20% of septuagenarians recalled as many words from a list as college students. Schacter cites studies that correlate this to education, with higher education better.

The temporal lobe, particularly the “parahippocampal gyrus” in the left brain,  appears to have meaningful relation to memory (one epilepsy patient whose temporal lobes were removed seemed to have extreme transience).  Additionally, memory works in an associative way – if you’re asked to state whether words are capitalized or not, you remember fewer of them than if you’re asked to state whether words are related to living or non-living things.  

(My psychology professor in community college actually ran a similar experiment on the class to amusing effect – one group vastly outperformed the other – or is this just a false memory?  🙂 )

Here, Schacter provides a useful overview of the different kinds of memory.  Within long-term memory, there’s “episodic” (personal experiences) and “semantic” (general knowledge and facts).  Before that, though, there’s “working memory,” which holds onto small bits of information for very short periods of time – and operates largely independently of long-term memory – but is what is responsible for an example Schacter cites that I know altogether too well myself: losing your train of thought in a conversation.

Moving back to long-term transience, two factors can interfere: first, just time, and second, interference by similar memories (ex – I often can’t remember which conversations I’ve had with which people because so many of my conversations seem to cover similar topics.)  

Sometimes information is wholly lost, but often, providing contextual clues can help – for example, the phenomenon of someone speaking a foreign language better, after many years of not using it, once they’ve gone to a foreign country where that language is spoken, and walked around for a few days.)

Touching on the memorization techniques discussed in Moonwalking with Einstein (MwE review), Schacter quickly snuffs out any hope the reader may have that there’s Some Simple Way to Boost! Your! Memory! If you just (do XYZ).  

Discussing imagery mnemonics (though he doesn’t specifically mention the memory palace concept), he notes:

“many of the imagery techniques are complex, require considerable cognitive resources to implement, and are therefore difficult to use spontaneously.  The first few times you generate bizarre mental pictures and stories to encode new information, the process may be challenging and fun.

But the task of repeatedly generating memorable images can eventually become burdensome enough so that people stop engaging in it.  In one study… [barely one-third of older adults] reported using [the mnemonic] techniques in their everyday lives.”  

Commercial courses also tend not to have the promised effects.

The one approach that does work seems to be elaboration/association – dwelling on the topic and linking it to other things you already know – but the various “wonder drugs” that have been touted by some (ginkgo, etc) don’t seem to have a strong effect.  There are a few experimental treatments around NMDA receptors, but they had not been commercialized at the time of writing the book.

Schacter moves on to the second topic, absent-mindedness; he concretely illustrates the difference between this and transience with an analogy about Tatiana Cooley, the National Memory Champion of 1999: she describes herself as “incredibly absent-minded” and “live[s] by Post-Its.”  

(Interestingly, per Moonwalking with Einstein, journalist Joshua Foer, after winning the 2006 memory championship, also still had trouble remembering where his keys were – see these notes.)  

The difference is explainable by the following: while “transience” represents a loss of information that was encoded, “absent-mindedness” represents information that was never properly encoded in the first place – as in the classic example of putting your keys/glasses/water bottle down while you’re thinking about something else, and then having no recollection of when or where you left it.  

Schacter cites some studies of divided attention, concluding that multitasking makes memory harder.  Laurence Gonzales touches on this as well in “ Deep Survival (DpSv review + notes) from a different angle, as does Shawn Achor in The Happiness Advantage (THA review + notes).

Interestingly, this is the second negative impact of multitasking on performance – see Cal Newport’s “ Deep Work” ( DpWk review + notes) – I wonder if there are any related neurological mechanisms at play?

In any event, fragmented attention seems to diminish specific “recollection” but not “familiarity” – i.e. you’ll recognize someone’s face, just not know who it belongs to… there’s an interesting discussion of “operating on automatic” on pages 46-47 (which I also distinctly remember my psych professor discussing.)  

Schacter references the famous basketball-passing experiment experiment (worth watching/doing if you haven’t ever heard of it) as an example of attention-driven change blindness.

 Schema /selective perception.

Long-term memory is improved by distributed repetition rather than cramming.  This makes sense based on the information presented earlier about what I termed decay curves…

Schacter also discusses failures of “prospective” memory, i.e. forgetting to do something that you’re supposed to do in a certain situation or time (amusingly, I literally just a few hours ago forgot to ask for extra rice at Chipotle, which I was planning to do.)

He notes the interesting societal dichotomy – we blame memory for failures of retrospective memory, but view the person as bad/lazy/etc when they forget to do something they should’ve.  Is this an innate human tendency or an example of culture?

Schacter suggests external reminders that are “sufficiently informative and distinctive.”  (See my structural problem solving model.)  I’ve tried to implement this myself – for example, I’ve (mostly) solved the problem of forgetting to take items with me somewhere by putting my car key in/on/next to them – I can’t physically leave without the item.

See also Don Norman’s The Design of Everyday Things (DOET review + notes) for more on forcing functions, etc.

The third “sin” is “blocking,” which refers to the “tip of the tongue” phenomenon.  Blocking appears to have to do with association; there is a “baker/Baker” phenomenon where people tend to remember occupations better than last names, and tend to remember descriptive character names (“Scrooge”) more than names that aren’t descriptive.

(Interesting read-across here to Richard Feynman’s classic discussion of the name of a bird – i.e. utility.)  Schacter goes into detail about the cognitive cause of this, as well as a fascinating discussion of a patient with “proper-name anomia” (he could remember everything but could not, unprompted, recall proper names).

The short/reductionistic version is that there are fewer associative links between someone’s nameand other things – which is why you can often remember what something means or is but not the name.  (This is, intriguingly, a very strong repudiation of the defense of memorization in education offered by Ian Leslie in “Curious” C review + notes).)  The rest of the chapter is less interesting for my purposes..

The fourth chapter covers the concept of “misattribution” – i.e. “assigning a memory to the wrong source,” which can include mixing up thoughts and reality (did I visualize myself closing the garage door or actually doing it?) or not knowing the source of something (i.e. thinking you heard something in one place when you heard it in another, or thinking you came up with something yourself when in fact you didn’t – this being referred to as “cryptomnesia” – and can lead to accidental plagiarism).  This one is actually really important for analysts…

Chapter 5 is perhaps the most chilling of the book, covering “suggestibility” – the idea that we can remember (or at least admit to remembering) things which we never encoded in the first place – Schacter cites the example of over half of Dutch study participants saying “yes” when researchers asked them if they had seen footage of a recent, extremely-publicized plane crash (when in fact no such footage of that crash even existed).  

Similarly, Schacter cites an example wherein if you are provided with footage of a certain event, then later shown pictures that may not actually have been from that event, you may remember the scenes depicted in those pictures as having happened.

This is a tough chapter to read, because there’s a lot of material about issues like false confessions, the ex post facto establishment of supposedly “repressed” memories via vivid visualization thereof, the unreliability of eyewitness testimony (which can often end up putting people in jail for horrible crimes they didn’t actually commit).  One of Schacter’s key takeaways about suggestibility:

remembering the past is not merely a matter of activating or awakening a dormant trace or picture… but instead involves a far more complex interaction between the current environment, what one expects to remember, and what is retained from the past.”

One of the interesting takeaways is the idea of the “cognitive interview” – rather than asking suggestive/leading questions, if you ask witnesses to try to remember everything they can, have them try to reinstate the context, remembering events both front-to-back and back-to-front, and taking different perspectives (i.e. perspective of perpetrator and the victim), you end up with more complete recall.  

While this can stimulate recall of inaccurate memories, Schacter seems to believe that the frequency is far less than that of “leading questioning.”  [This has implications for interviewing management, or even interviewing people for historical purposes – if you ask open-ended rather than leading questions, you’re more likely to get the right answer.  See also Tavris/Aronson in “ Mistakes were Made ( mwm review + notes) on the ‘Reid Technique.’]

The sixth sin, “bias,” also has meaningful applicability in both work and life: Schacter’s concise introduction is that:

“our memories of the past are often rescripted to fit with our present views and needs.”  

See Christopher Browning’s Ordinary Men (OrdM review + notes) for some good stuff on this.

Consistency bias: to reduce cognitive dissonance, we align “what we remember” to “what we are” – we are less likely to correctly recall information that conflicts with what we now believe

Hindsight bias: ex post, what was unclear ex ante seems obvious (the “I knew it!” phenomenon).  Schacter calls this “ubiquitous.

Egocentric bias: we tend to prioritize our own memories over those of others… related to “fundamental attribution error” and others.

Self-preserving bias – related, but more self-serving

See also Phil Rosenzweig’s “ The Halo Effect” (Halo review + notes)… pgs 50 – 57

Classic “interpreter” story about the man and the soda and the chicken claw on page 158… storytelling.

The final Sin is “persistence” – the persistent recollection of unwanted memories.  Schacter starts with the premise that emotion and memory are connected – emotion amplifies the intensity of memory, but only for the “central focus” rather than the “peripheral details.”

While both positive and negative emotions strengthen memory, negative events are remembered in greater detail.  Unsurprising, given loss aversion.

Moreover, reminders thereof can strengthen recall, and can cause “ counterfactual thinking” (i.e. “if only”).  This isn’t the good sort of counterfactual, by the way; it’s more analogous to the bad if-only, multicausality ignoring thinking discussed by Don Norman in “ The Design of Everyday Things ( DOET review + notes).

Schacter notes that your schema and worldview have an influence on persistence, citing the example of a golf pro who spectacularly failed in the public eye, and totally shrugged it off.  Depression tends to be both a result of and a cause of persistence.

Moreover, intentional attempts to suppress memories unfortunately interfere with the “habituation” process whereby these memories are dealt with over time.  Schacter goes on to discuss some of the underlying mechanisms, particularly the amygdala, and concludes that stress can be a trigger of persistence.

Schacter concludes with a discussion of why he believes that all these “sins” are ultimately features, not bugs, or at the very least incidental byproducts thereof – insightfully, he notes that we never see the positive counterfactuals, i.e.:

“A system that renders information less accessible over time is therefore highly functional, because when information has not been used for longer and longer periods of time, it becomes less and less likely that it will be needed in the future.  

On balance, the system would be better of setting aside such information… [our memory… makes a bet that when we haven’t used information recently, we probably won’t need it in the future.  

We win the bet more often than we lose it, but we are acutely aware of the losses… and never aware of the wins.”  

(Similar justifications are available for the other sins.)  And, yay salience!

While the idea of a photographic memory is often romanticized in film or fiction, Schacter notes when recounting an anecdote about a famous Russian mnemonist –

“he was unable to function at an abstract level because he was inundated with unimportant details of his experiences.”  

Schacter also references how the same neurological mechanisms that enable autistic children and adults to have amazing memories can prevent them from effectively generalizing.


First Read: 2016

Last Read: 2017

Number of Times Read: 3 (because I forgot what it said)

Planning to Read Again?: maybe


Review Date: summer 2017

Notes Date: summer 2017