Cue theory: asking better questions

We want students to know that Harrison Ford played Han Solo in the Star Wars films.

Which question is it better to ask?

  1. Which actor played Han Solo in the Star Wars films?
  2. Which character did the actor Harrison Ford play in the Star Wars films?
  3. Which actor played the charismatic owner of the Millennium Falcon?
  4. This Star Wars character’s best friend is a Wookie. What is the name of the character and the actor who played him?

Well, it depends on why you are asking the question.

Are you trying to check whether students have the desired knowledge?

Or do you hope to improve their ability to remember and retrieve this knowledge?

Either way, you need to know about cues and what effect they have.

What is a cue?

A cue is a signal that, if effective, will trigger the retrieval of the desired memory trace (aka ‘engram’).

Memory researchers theorise that retrieval is triggered by a process which is called trace-cue compatibility. Retrieval of the desired memory occurs when there is a match between the conditions within which the memory was encoded and the conditions of retrieval (Tulving, 1983).

In other words, there must be a functional link between the cues in a question and the way the information has been encoded in memory.

What are the cues in our questions? They are highlighted below in bold.

  1. Which actor played Han Solo in the Star Wars films?
  2. Which character did the actor Harrison Ford play in the Star Wars films?
  3. Which actor played the charismatic owner of the Millennium Falcon?
  4. This Star Wars character’s best friend is a Wookie. What is the name of the character and the actor who played him?

** The implied sex of the person in the word ‘actor’ and ‘him’ also acts as a cue, but a weak one.

In question 1, the mention of Han Solo should trigger the name of the actor Harrison Ford.

In question 2, the mention of Harrison Ford should trigger retrieval of Han Solo as the character he played. Whilst Q2 is simply Q1 in reverse, it is likely to result in more students answering correctly as the character will be more familiar than the actor to many.

The mention of tangential information in questions 3 and 4 – a character trait (“charismatic”), reference to a Wookie, and reference to the Millenium Falcon – provides more cues, but less direct ones. We may assume these questions will be more cognitively demanding and result in fewer correct responses. Intuitively, these are ‘harder’ questions.

However, questions 3 and 4 test more than whether students know that Harrison Ford played Han Solo. They are better questions for finding out more generally what students know about the character as well as who played him.

How should we use cues?

If our goal is to improve retention of the desired knowledge in long term memory, asking lots of questions which use a variety of cues will help. This helps students create multiple, strong links in their mental schema.

If our goal is to strengthen retrieval of the desired information, we should also make the questions desirably difficult i.e. minimal cues. This forces effortful retrieval, which clears pathways to the memory traces.

If our goal is to make inferences about whether the student knows what we want them to know, we must select cues very carefully. Why?

Cue selection for checking knowledge

In our example, we may want to know whether the student has the desired memory traces. We may describe these engrams as follows:

  • The actor’s name Harrison Ford
  • The character name Han Solo
  • That these are connected as one plays the other in the film Star Wars.

When we ask a student our chosen question, there are three possibilities, which are that the student:

  1. Doesn’t know it so can’t show it
  2. Knows it but doesn’t show it
  3. Knows it and shows it.

We want to avoid no. 2 as this may lead us to incorrectly infer that they do not know what we want them to know.

Retrieval is a discriminatory process. Students must search their memory for the traces we want to check are there and decide which of a range of possible responses is relevant . We should aim to signal to students what memory we want them to retrieve, but not direct them to the answer.

In other words, we should provide cues, not clues.

The worst example of clues are where the teacher resorts to saying things like ‘His initials are HF’!

Cue choice

But which cues do we choose? And how many?

This is where the theory of trace-cue compatibility, mentioned at the start of this post, is useful.

We must select cues which have a cue-target match. This means the cues must be associated in the minds of the students with the memory traces when these were encoded.

For example, if there was no mention of the Millennium Falcon as being Han Solo’s spaceship when we taught the topic, it will not serve as a cue. If we only mentioned it in passing, it will be a weak cue and may produce unreliable information about whether students know what we want them to know.

We may be tempted to employ multiple cues. For example, we might frame a question thus:

Harrison Ford played a gun-toting, smuggler in Star Wars whose spaceship, the Millenium Falcon, was the means of escape for him and his pal Chewbacca on many occasions. What was the name of his character?

This is a scattergun approach. It may generate more right answers, but it doesn’t tell us clearly whether the precise memory traces are present in the desirable form: that the actor and character’s name are known and linked in memory.

Multiple cues may also result in fewer correct responses. First, the student may lose the thread of the question. Second, the inclusion of more cues may increase the number of ‘possible responses’ from which the student must select.

For example, including the phrase ‘owner of the Millenium Falcon’ in the question as an additional cue in fact opens up other possible answers. A student may know that the Millennium Falcon was actually stolen from Jabba the Hutt, the true owner of the ship. Or they may be familiar with the recent films in the series in which the ship is in the possession of characters other than Han Solo.

The pool of possible answers is increased by the inclusion of additional cues and makes the task of discriminating between these answers more challenging. The executive function known as response inhibition becomes more difficult.

So, more does not necessarily mean better when it comes to cues.

Discriminatory cues

Cue-target match is a necessary but not sufficient condition for retrieval. It is not enough just to provide lots of cues which correlate to the desired memory traces.

What is also important is the extent to which the cue is uniquely associated with a memory.

A retrieval cue must enable the responder to discriminate between possible answers.

If retrieval cue A is associated with engram X, Y or Z, it cannot be used to discriminate between these possible responses. However, if retrieval cue B is exclusively associated with engram Z then discrimination is certain.

In relation to our questions, we may note that:

  • the character Han Solo was played by more than one actor in the films (there was a spinoff in which Han Solo was played by Alden Ehrenreich), but;
  • Harrison Ford only played one character in the series.

Therefore, the question ‘Which character did the actor Harrison Ford play in the Star Wars films?’ is the only one which provides information which enables a student to discriminate between possible responses accurately – as long as they know their stuff!

Cue end-credits

What have we learnt about cues?

  1. Cues play a key role in retrieval
  2. Cue selection depends on why we are asking the question – for retention, for retrieval strengthening, or for making inferences?
  3. In any case, we want cues, not clues
  4. The cue must be chosen from those that were part of the original encoding, known as cue-target matching (Thomson & Tulving, 1970)
  5. A larger number of cues is not always helpful as they may ‘recruit additional members’ into the set of possible responses (Nairne, 2002)
  6. For successful retrieval, cue-target matching is required, but it is the presence of discriminatory cues that will improve performance (Eysenk, 1979).

If they know it, we want them to show it. That is all down to cue choice.

Eysenk (1979), Depth, Elaboration, and Distinctiveness.
Nairne (2002), The Myth of The Encoding-Retrieval Match.
Thompson & Tulving (1970), Associative Encoding and Retrieval: Weak and Strong Cues.
Tulving (1983), Elements of Episodic memory.

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