Twenty Thousand Leagues: Depth of Processing

Learning By Doing

Without cheating, take a moment to scan the following matrix of pennies. 

Which drawing represents the current design of a penny? (Fun fact: the front-side of a coin is called the obverse.)

Figure 1. Can the real penny please stand up?

Once you've made your selection, reflect on the following questions:

1. Was this a difficult task?
2. If so, why was this difficult?
3. If not, what life experience did you have that prepared you to answer quickly and accurately?

Like a Bad Penny...

I've used the penny demonstration in several groups over the past year, and I would estimate that about 1 in 30 select the right coin [1]; therefore, it's likely this task was hard for you, too. The question is why (despite the fact we've all seen a penny many, many times)? 

One reason is related to the first of three processes in our simple model of memory: encoding. You might be unable to identify the real penny, in a sea of distractors, because you never encoded the specific properties of a penny. 

On the other hand, you probably did encode the approximate size, the edge's smoothness, the inclusion of our 16th president, and the copper veneer. You encoded those properties because they help you meet your learning goal: to spend a penny. You need to differentiate a penny from a nickel, dime, and quarter. In other words, learning is goal oriented. If your goal changes (e.g., you need to accurately draw a penny for your blog), then you will encode those specific details.

That's Deep.

Misidentifying a penny among 14 distractors is a pretty powerful example of encoding failure. We've all seen a penny before, but it's unlikely that someone quizzed you on the specific features. So what if they did? Is there a way to enhance our ability to remember something over the long haul? In other words, is all processing is equally effective? I'm sure the answer is obvious to you. But what's the evidence?

To test if different levels of processing lead to better (or worse) memories, two very famous memory researchers, Fergus Craik and Endel Tulving, conducted a series of experiments [2]. They asked volunteers to come to their lab and study a list of words. They experimentally manipulated how deeply the participants studied the words across five levels of processing. They asked the participants (1) if the word was present; (2) if the word was written in capital letters; (3) if the word rhymed with another word; (4) if it was in a specific category;  or (5) if it fit into a given sentence. Table 1 contains both positive and negative examples for the word honey.

Table 1. The experimental manipulation of processing depth. 

Level of Processing	Positive Example	Negative Example
1. Is there a word present?	HONEY
2. Is the word in capital letters?	HONEY	honey
3. Does the word rhyme with ___?	funny	monk
4. Is the word in a category of ___?	a type of food	a part of a ship
5. Does the word fit in this sentence: ___?	He eats ______ on his toast.	She met a ____ on the street.

Before you look at the results, what do you predict they found? Does processing a word at a deeper, more semantic level, lead to better memory trace? Or is processing all the same, as long as it passes through the attentional system and into working memory? 

Here's what they found: 

Figure 2. Memory accuracy as a function of depth of processing.

According to their results, there is a huge advantage for processing a word at a deeper, semantic level. 

The Classroom Connection

The evidence from Craik and Tulving's study is highly suggestive. As educators, we want our students to process the information we want them to learn as deeply as possible. This advice is consistent with other research on memory:

1. We saw evidence that generating a to-be-remembered item can also have beneficial effects on long-term recall. 
2. Research on retrieval practice demonstrated that rereading notes or a chapter summary was a terrible way to study. Instead, students should engage in an effortful attempt to retrieve the information from memory. 
3. We also reviewed a study that showed students prefer easy hints to more difficult hints when self-testing. Unfortunately, their preferences ran completely counter to the empirical evidence suggesting that more effortful retrieval leads to better retention. 

Because encoding is a vitally important step for robust learning, it is helpful to understand what the empirical data has to say: The deeper the processing, the longer lasting the memory. 

Process that as deeply as you can! 🦑

Share and Enjoy!

Dr. Bob

Going Beyond the Information Given

[1] By the way, the right answer is (a). Don't believe me? I bet the US Mint will back me up.

[2] Craik, F. I., & Tulving, E. (1975). Depth of processing and the retention of words in episodic memory. Journal of experimental Psychology: General, 104(3), 268.