The idea of enhanced or superior memory is a theme that has long fascinated cognitive researchers and society in general. It has been the theme of various novels, films, and probably an equal number of academic journal articles. The single question motivating both works of fact and fiction is, what techniques might an individual employ to enhance memory performance?
In fact, as a Cognitive psychologist studying episodic memory, I also find memory techniques to be an interesting question. In fiction, this question is partially the reason why Sherlock Holmes (BBCs version with Benedict Cumberbatch! No offense Robert Downing Jr.) is one of my favorite detectives.
Sherlock Holmes is infamous for his biting sarcasm, superior skills of deduction, and my favorite, his excellent use of his mind palace (memory palace). A memory palace (more traditionally known as method of loci) is a technique of efficient encoding and retrieval of information from memory.
Briefly, to use a memory palace, individuals imagine visiting a place that they have often frequented, such as a home or office. As in this video here:
Along the way, people can ‘store’ information in different locations in the ‘palace’. For example, an individual can imagine moving through a house, and along the way, they store grocery items in different rooms like butter and cheese in the coat closet, bread in the bathroom, and so on. During retrieval, they can imagine walking this same route and retrieve the information (grocery items) stored in the various locations.
While a memory palace may be imaginary, the decades of research geared toward evaluating techniques to enhance memory performance are quite real. One such technique that research has deemed effective is “testing-based retrieval practice”, which requires that individuals rehearse retrieving information from memory prior to taking a memory test. In other words, quizzing oneself on to-be-remembered information can lead to better memory, especially compared to re-studying the information. An example of testing-based practices is using flash cards where a person tries to recall the information before turning the card over to reveal the correct answer.
One potential limitation of this technique is that it might only be effective when the studied information can be retrieved, or feedback about retrieval is provided. For instance, imagine trying to recall Sherlock Holmes’ landlady’s name. If I am never able to recall her name, or if no feedback is given regarding whether or not my guess is correct, then practicing retrieving a name is pointless (The landlady’s name is Mrs. Hudson by the way!). This is equivalent to using a flashcard with no correct answer on the back. There is no way of determining if a response is correct.
However, a potential remedy for this limitation is a technique known as “scaffolding”. Scaffolding is an educational training technique where individuals are provided progressively less assistance until no assistance is required. For example, when trying to remember Sherlock’s landlady, I might be given the cue “Mrs. H____n” on my first practice round, and ”Mrs. H_” on my second practice. By the third round, I may no longer need assistance via cues and I should be able to successfully retrieve the name “Mrs. Hudson”. This technique of providing progressively fewer cues during scaffolding is known as diminishing-cue retrieval practice.
Theoretically, scaffolding should improve testing-based practices across task difficulty, but empirically this warrants investigation.
To this end, in a recent article in the Psychonomic Bulletin and Review, researchers Joshua Fiechter and Aaron Benjamin examined whether diminishing-cue retrieval practice could aid learning and retrieval from memory, particularly in conditions where standard retrieval practice confers little memory benefit.
Fiechter and Benjamin hypothesized that diminishing-cue retrieval practice might be more beneficial when target information is difficult to retrieve (i.e., the study stimulus is difficult to remember) and no feedback is provided (first set of studies). In contrast, standard retrieval practice might be sufficient (i.e., diminishing-cue retrieval might be unnecessary) when the target information is less difficult to retrieve, even when no feedback is provided (second set of studies). Lastly, standard retrieval practice might be sufficient and potentially equivalent to diminishing-cue retrieval practice when the target information is difficult to retrieve (like the first set of studies), but feedback is provided (third set of studies).
To test this hypothesis, the researchers conducted three series of experiments. The methodologies were relatively similar across the three series. However, the critical differences were the difficulty of the study stimuli (set 1 and set 3 were difficult, and set 2 was easier), and whether feedback was provided (feedback was provided in set 3, but not in set 1 or set 2).
Across all three set of studies, the experiments were carried out in four phases: a study (or practice) phase, a distractor phase, a retention interval, and finally a testing phase. During the study phase, participants studied pairs of words for four seconds each. During the distractor phase, participants completed a 60-second go/no-go task. The retention phase was the length of time between practice and testing (the retention interval only varied within the first set of studies, and it was 24 hours for all other studies). Lastly, during the testing phase, participants were presented with a word cue (one of the items in the word pair) one at a time in random order and were asked to recall the target word associated with the presented cue.
The critical manipulation involved the three types of practice participants received. For the restudy practice, participants were shown the complete study pair and were asked to type in the target word. For the standard retrieval practice, participants were shown a cue word and were asked to type in the target word. For the diminishing-cues practice, participants were shown a cue word along with a portion of the target word and were asked to type the target word. Importantly, in the diminishing-cues condition, letters were randomly dropped over subsequent rounds of practice until no letters were provided and participants needed to produce the entire target word (see figure below, panel a.).
The results for the first set of studies, where the target information was difficult to retrieve and no feedback was provided (standard practice confers little benefit), revealed no advantage for standard retrieval practice over restudy, but an advantage for diminishing-cues retrieval over both standard retrieval and restudy (panel b.).
The results for the second set of studies, where the target information was easier to retrieve and no feedback was provided (standard practice might be beneficial), revealed a significant advantage for standard retrieval practice over restudy, and also an advantage for diminishing-cues retrieval over both standard retrieval and restudy (panel c.).
Finally, the results from the third set of studies, where the target information was difficult to retrieve but feedback was provided (standard practice might also be beneficial), revealed a significant advantage for both standard retrieval and diminishing-cues practice over restudy, but no difference between diminishing-cues and standard retrieval practice (figure panel d.).
Taken together, the results of these studies suggest that testing-based retrieval practice is still a very effective technique for memory and that the benefit of this technique can be generalized across a broader spectrum of tasks that differ in difficult, by incorporating a scaffolding technique such a diminishing cues.
Just like in the fictional world where techniques for enhancing memory retrieval have been identified (like Sherlock’s memory palace), in the real world cognitive researchers are also making significant advances in identifying memory-enhancing techniques: namely diminishing-cue retrieval-based practicing!
Featured Psychonomic Society article:
Fiechter, J. & Benjamin, A. (2018). Diminishing-cues retrieval practice: A memory-enhancing technique that works when regular testing doesn’t. Psychonomic Bulletin and Review DOI: 10.3758/s13423-017-1366-9.