Why We Remember Some Things Better Than Others?

A 1984 study

Which of the following short paragraphs would you remember best? They are ranked by how closely the two sentences are related, from strongest to weakest, and they all end the same way:

Level 1. “Joey’s big brother punched him again and again. The next day his body was covered with bruises.”

Level 2. “Racing down the hill, Joey fell off his bike. The next day his body was covered with bruises.”

Level 3. “Joey’s crazy mother became furiously angry with him. The next day his body was covered with bruises.”

Level 4. “Joey went to a neighbor’s house to play. The next day his body was covered with bruises.”

You might choose the first one (Level 1) because the punches lead directly to the bruises. Or you might choose the fourth (Level 4) because it leaves a mystery.

In 1984, three memory researchers asked 36 students at the University of Denver to read short paragraphs like these (Keenan et al., 1984). Each student saw only one version of Joey. Then, after about half an hour of other reading tasks, the researchers asked: how did Joey get his bruises?

The results? Across the paragraphs, average recall was 69% for the strongest causal links (Level 1 punching), 83% for Level 2 (falling off the bike), 75% for Level 3 (angry mom), and 50% for the weakest links (Level 4 going to a neighbor’s house).

The weakest links (Level 4) were recalled significantly less often than every other level (p < .01). The trend is clear: recall rose and then fell across the four levels (p < .001). And the gap between Level 2, the bike, and Level 1, the punching, was marginally significant (p < .10).¹

You may wonder why the fall from a bike (Level 2) was remembered so well.

The researchers offered one explanation. When one event almost inevitably leads to the next event, the reader does not need to do much mental processing. Repeated punches, for example, already bring bruises to mind. However, when the connection is less direct but still plausible, the reader has to actively search for the missing link. A fall from a bike does not always cause bruises, but you can imagine how this can happen. The small effort required to make that inference may lead the reader to process the information more deeply.

You might argue that the Level 4 paragraph required even more mental work and should therefore have produced the best recall. So what happened there? The researchers proposed that the extra processing of the paragraph did not produce a firm causal connection. A visit to a neighbor could lead to bruises in many ways, and the two sentences did not provide a firm answer. “If increased processing only results in a tenuous causal connection”, the researchers concluded, “then it cannot facilitate memory” (Keenan et al., 1984, p. 125).

Memory is as thinking does

Daniel Willingham, a cognitive psychologist who writes for teachers, stated the same principle in five words: “Memory is as thinking does” (2003, “Memory Is as Thinking Does” section). Learners do not necessarily remember the material we give them. What they remember is what they think about as they process it. The two do not always line up. Much of the craft of teaching lies in bringing them together.

Willingham illustrates this mismatch with an example. A teacher asked his students to bake biscuits so they could appreciate what escaped slaves ate on the Underground Railroad. These students had probably spent 30 seconds thinking about how the biscuits were related to the course material, and then 30 minutes thinking about measuring flour and mixing dough. If memory follows thought, Willingham suggested, baking biscuits is likely to be what they remembered!

What does it mean for learning design?

Together, the 1984 study and Willingham’s article raise a design question that neither of them directly addresses: How much of the connection should we reveal when designing instruction?

If we explain every step before learners have a chance to think, they may follow easily but do little thinking themselves. But if we leave out a crucial step, they may miss the intended connection or construct a plausible but incorrect one. A useful approach is to leave a gap that learners can close by thinking with what they already know.

In practice, we can present an outcome first and ask what might have caused it, or show two events and ask learners to explain the connection. Then we can provide the missing information and introduce the concept that makes sense of the relationship. Consider a lesson on confirmation bias. Instead of beginning with a definition and a list of common mistakes, we could introduce a hiring manager who believes a new interview method works. She points to every successful hire who passed the interview but explains away every unsuccessful one. We could ask learners what evidence she accepted, what she dismissed, and whether her conclusion was justified. After they examine her reasoning, we would introduce confirmation bias as the concept that explains the pattern.

Finally, before designing an activity, follow Willingham’s own rule for teachers: “Anticipate what your lesson will lead students to think about” (2003, “What Does This Mean for Teachers?” section). The activity supports learning when that thinking focuses on the concept or idea you want them to learn. If it does not, learners may remember an enjoyable experience while forgetting the lesson it was meant to teach.

References

Keenan, J. M., Baillet, S. D., & Brown, P. (1984). The effects of causal cohesion on comprehension and memory. Journal of Verbal Learning and Verbal Behavior, 23(1), 115–126.

Willingham, D. T. (2003). Ask the cognitive scientist: Students remember… what they think about. American Educator, 27(2), 37–41.