Applying Cognitive Psychology to Enhance Educational PracticeThe primary goal of this research, which is funded by the James S. McDonnell foundation, is to promote learning and memory performance within educational contexts through the investigation of principles in cognitive psychology. Studies address issues of transfer-appropriate and material-appropriate processing between encoding and retrieval. Applying tests in order to enhance learning and determining the desirable amount and timing of feedback regarding an individual's memory performance are methods that are currently under investigation.
The overlying theme of "desirable difficulties," first introduced by Robert Bjork (1994), is also explored through manipulations in the spacing of learning events and the study schedule produced by interleaving various to-be-learned items, such as English-Swahili translated word pairs or prose materials. Interleaving occurs when a to-be-learned target item is initially presented and followed by different to-be-learned items prior to the target's subsequent presentations. An interleaving schedule used during the presentation of a painting matched with the name of the artist has been shown to lead to better performance on later recognition tests when compared with a massing presentation schedule in which each painting and artist name was presented back-to-back, with one presentation immediately followed by the next presentation of a different painting by the same artist (Kornell & Bjork, 2008).
Studies have also looked at the effectiveness of similar choices used in multiple choice tests for future test performance as well as the act of generating items when they are presented with missing letters. Additional research is targeted towards understanding the role of an individual preparing to teach on that individual's subsequent learning and test performance.
This line of work is also directed toward understanding the mechanisms behind metacognitive awareness of learning. Most people are inaccurate in measuring their own knowledge, through judgments of learning, because they mistakenly rely on the immediate access to knowledge in order to determine the long-term memory retention and the transfer of such knowledge to different contexts. The goal of these studies is to determine the type of instructions and study conditions that will foster accurate judgments of learning, which can lead to better predictions of future performance and optimal self-initiated study practices.
I. Retrieval as a Memory ModifierWe draw upon our memories for a variety of reasons: We may recall something in order to relay a story to a friend. We may take a test to double-check that we know important material. Or, we may recall information in order to help us remember other details or to solve a problem. However, a much underappreciated fact is that retrieval itself can affect our memories.
Taking a test often does more than assess knowledge; tests can also provide opportunities for learning. When information is successfully retrieved from memory, its representation in memory is changed such that it becomes more recallable in the future (e.g., R. A. Bjork, 1975); and this improvement is often greater than the benefit resulting from additional study (Roediger & Karpicke, 2006). Interestingly, taking a test can modify memory for information that was not explicitly tested initially (provided that the untested information is related to the tested information in certain ways; Anderson, R. A. Bjork, & E. L. Bjork, 1994; Chan, McDermott, & Roediger, 2006; Hamaker, 1986). Sometimes later recall of this untested information is improved (see, e.g., Hamaker, 1986), but sometimes it is impaired (see, e.g., Anderson et al., 1994), often dependent upon the type of relationship existing between tested and untested information (e.g., Little, Storm, & E. L. Bjork, 2011).
Memory cues, whether categories, positions in space, scents, or the name of a place, are often linked to many items in memory. For example, the category FRUIT is linked to dozens of exemplars, such as ORANGE, BANANA, MANGO, KIWI, and so on. When forced to select from memory a single item associated to a cue (e.g., FRUIT: OR____), what happens to other items associated to that general, organizing cue? Using the retrieval-practice paradigm, we and other researchers have demonstrated that access to those associates is reduced. Retrieval-induced forgetting, or the impaired access to non-retrieved items that share a cue with retrieved items, occurs only when those associates compete during the retrieval attempt (e.g., access to BANANA is reduced because it interferes with retrieval of ORANGE, but MANGO is unaffected because it is too weak of an exemplar to interfere; Anderson, R.A. Bjork, & E. L. Bjork, 1994, Experiment 3). We argue for retrieval-induced forgetting as an example of goal-directed forgetting because it is thought to be the result of inhibitory processes that help facilitate the retrieval of the target by reducing access to competitors. In this way, retrieval induced forgetting is an adaptive aspect of a functional memory system.
New Theory of Disuse
Sometimes people cannot access information that was well learned earlier (e.g., the address of the house where they grew up). And students find that although they can recall information over and over again the day before a test, they cannot always recall it at the time of examination. Finally, sometimes people cannot recall information at one point in time, but can recall it later. In looking at these situations, it seems that our memories work in strange and unpredictable ways. The function of our memories, however, may be predictable. The New Theory of Disuse (R. A. Bjork & E. L. Bjork, 1992) posits that there are two indices of memory strength: storage strength (SS) and retrieval strength (RS). Storage strength is how well learned something is; retrieval strength is how accessible (or retrievable) something is. To illustrate, imagine four possible situations. If something is well learned (e.g., the address where you have lived for several years), it has both high SS and high RS: You know it well and can retrieve it readily. The address of a friend that you visited for the first time this afternoon, however, may only have high RS (and low SS) because the address, although practiced recently, was not well learned. Thus, although you know the address now, you will be unlikely to be able to recall it in a few days because RS will decrease over time, especially for information with low SS. Sometimes information has high SS (due to it having been well learned), but cannot be retrieved (e.g., the address where you lived as a child). If you were provided with this address again, however, you would have the feeling that that information was somewhere in the recesses of your memory, and in fact, you would be likely to relearn it very quickly. Finally, information can have both low RS and low SS. This information would include things that you heard in class earlier today, but did not learn well and cannot recall now.
II. How We Learn versus How We Think We Learn: Desirable Difficulties in Theory and Practice.
Introduction to Desirable Difficulties
Imagine a scenario in which a teacher has students practice different examples of a single type of math problem for an hour in class. By the end of the hour, it may seem—both to the teacher and to the students—that this type of math problem has been mastered. On a test two weeks later, however, the benefit may not be evident. In fact, much to the dismay of the teacher and the students, performance during training is not always representative of long-term learning.
In contrast to the story told above, in which an easy training method was followed by poor performance later, imagine that the teacher had interleaved many different types of problems during in-class training drills. Recent research reveals that difficult training of this type produces higher scores on the test than the easier version described above (Rohrer & Taylor, 2007), and this is the kind of training that the Bjork Learning and Forgetting Lab believes enhances long-term learning.
It is common sense that when we want to learn information, we study that information multiple times. The schedules by which we space repetitions can make a huge difference, however, in how well we learn and retain information we study. The spacing effect is the finding that information that is presented repeatedly over spaced intervals is learned much better than information that is repeated without intervals (i.e., massed presentation). This effect is one of the most robust results in all of cognitive psychology and has been shown to be effective over a large range of stimuli and retention intervals from nonsense syllables (Ebbinghaus, 1885) to foreign language learning across many months (Bahrick, Bahrick, Bahrick & Bahrick, 1993).
One robust and longstanding finding is that generating words, rather than simply reading them, makes them more memorable (Slamecka & Graf, 1978). As an example, this effect is often achieved for single words through the use of a letter-stem cue (ex. "fl____" for "flower") or by unscrambling an anagram (ex. "rolwfe" for "flower"). The effects of generation on memory are being investigated from many different angles in the lab, from its basic role as a memory modifier (see Desirable Difficulties), to people's awareness of this role and subsequent use of generation as a strategy (see Metacognition), to the extended effects of generation on related material (see Retrieval-Induced Forgetting).
Spacing is one of the most robust, effective ways of improving learning. However, spacing calls for intervals of time in between repetitions, and this may not be the most efficient use of time. Imagine you have three final exams to study for. If you were to space out study of three whole courses, you might as well start your course review before the quarter even begins! Particularly when one has several different things to learn, an effective strategy is to interleave one's study: Study a little bit of history, then a little bit of psychology followed by a chapter of statistics and go back again to history. Repeat (best if in a blocked-randomized order).
Perceptual desirable difficulties
Fluency, or the subjective ease of processing information, can provide learners with a useful basis for judging how well information has been understood. Perceptual variations are among the most obvious--and, sometimes, the most misleading—cues to the fluency of information. For example, when you encounter fonts that are difficult to read or words in very small print, you may experience a sense of disfluency—that is, you may have a feeling that the unusual or small typefaces are more difficult to process than more common typefaces.
Interactions between desirable difficulties It is not enough to simply provide educators with a list of desirable difficulties and claim that our work in optimizing learning has been completed. It may be that certain combinations of desirable difficulties interact to yield super-additive or sub-additive effects, if the processes by which the desirable difficulties work enhance or interfere with each other. Research into these interactions is therefore important on both practical ("What is best for learning?") and theoretical ("How do these desirable difficulties work to influence memory?") levels. For instance, research investigating the combination of spacing and variation in advertisements (Appleton-Knapp, R. A. Bjork, & Wickens, 2005) has shown that whilst spacing and variation are each independently 'desirable', there is a sub-additive interaction between the two manipulations such that variation is beneficial only when spacing intervals are short. At longer spacing intervals, variation actually hurts memory performance. Furthermore, the results of this study supported the study-phase retrieval theory of spacing over the encoding variability theory of spacing (see Spacing). Current studies in this line of research include examining the interactions between spacing and generation and spacing and variation with educationally relevant materials, such as text passages and glossary-style definitions. Interactions are also being explored with inductive learning, and Kornell, Birnbaum, Bjork & Bjork (in preparation) have found a subadditive effect of spacing and interleaving in the induction of butterfly species (see Interleaving). Back to Table of Contents
III. Learning concepts and categories (Inductive learning).We are constantly faced with the challenge of categorizing and organizing the world into meaningful units of information. For example, when we meet our friend's pet, we are immediately able to recognize it as a dog rather than a large rat with a collar. This knowledge is acquired through a process called inductive learning: although we have not seen this particular dog before, we have seen many examples of dogs and other animals, and from those experiences we have induced the category of "dog." This same process takes place in educational settings. Forms of inductive learning include differentiating a novel Monet painting from a Picasso painting, or a cancerous cell mass from a benign one. The Bjork Learning and Forgetting Laboratory investigates the cognitive mechanisms that mediate inductive learning and ways to optimize this type of learning. This endeavor is especially important because our findings indicate that the learning methods people believe are most beneficial are often not (see Metacognition section). Kornell and R. A. Bjork (2008) found that while many students believe that studying examples of a category all at once leads to more effective inductive learning than studying them intermixed with examples of other to-be-learned categories, the opposite is in fact true (see Interleaving). Back to Table of Contents
IV. Goal-Directed ForgettingPeople often view forgetting as an error in an otherwise functional memory system; that is, forgetting appears to be a nuisance in our daily activities. Yet forgetting is adaptive in many circumstances. For example, if you park your car in the same lot at work each day, you must inhibit the memory of where you parked yesterday (and every day before that!) to find your car today.
Much work conducted in the Bjork Learning and Forgetting Lab has focused on goal-directed forgetting, that is, situations in which forgetting serves some implicit or explicit personal need (E. L. Bjork, R. A. Bjork, & Anderson, 1998). In recent years our research has supported the notion that mechanisms of inhibition—analogous to those proposed in many areas of lower-level cognition, such as vision (explain, perhaps parenthetically)—play an important role in goal-directed forgetting. We have developed and utilized a variety of experimental paradigms to investigate phenomena that exemplify goal-directed forgetting, including directed forgetting (R. A. Bjork, 1979) and retrieval-induced forgetting (Anderson, R. A. Bjork, & E. L. Bjork, 1994).
Forgetting is often viewed as an uncontrollable, undesirable failure of memory. Yet it is possible to experimentally induce forgetting in an individual that can lead to unexpected benefits. One such paradigm is known as "directed forgetting." In the typical list-based directed forgetting paradigm (E. L. Bjork & R. A. Bjork, 1996), a participant will study two lists of words, and is notified after each list whether or not it will be tested later on. If a list is tested after the learner was notified that it would not be tested, the learner will show weaker recall for that list, compared to a baseline condition in which all lists are expected to be tested, demonstrating the costs of directed forgetting. Interestingly, it is commonly found that recall of any list that was expected to be tested will be greater than that of the baseline condition, demonstrating the unexpected benefits of directed forgetting.
V. MetacognitionMetacognition refers to the subjective awareness of one's own knowledge. In the Bjork Learning and Forgetting Lab, we focus on how this relates to learning and study behaviors, or metamemory. Metamemory consists of both monitoring the state of one's memory (or lack thereof) as well as using this information to control study decisions. Accurate metamemory can be crucial for a student in determining the success of his or her own study program.
Fluency and biases Metamemory can be remarkably accurate in certain contexts, but this is not always the case. For instance, metacognitive monitoring seems to rely on the fluency of an item at encoding (i.e., when it is first learned; for more on this topic, see Perceptual Desirable Difficulties). This is often an accurate basis on which to make judgments, but the Bjork Learning and Forgetting Lab has shown that people still rely on this type of fluency even when it is misleading (e.g., Benjamin, R. A. Bjork, & Schwartz, 1998; Koriat & R. A. Bjork, 2006). Learners also fail to take into account forgetting that occurs over time (Koriat, R. A. Bjork, Sheffer, & Bar, 2004) and learning that occurs with repetition (i.e., the "stability bias", Kornell & R. A. Bjork, 2009); they instead seem to assume that what they know at the time the judgment is made is an accurate reflection of what they will know at a later time point. Back to Table of Contents
Awareness of study strategies Another important issue in metamemory is people's awareness of the effectiveness of different study strategies. Zechmeister and Shaughnessy (1980) showed that people tend to think massed repetitions are more effective than spaced repetitions. Massed repetitions lead to greater short-term performance, but impair long-term performance (e.g., Simon & Bjork, 2001); this dissociation could explain why people think massed repetitions are more effective. Kornell and R. A. Bjork (2008) found that in the case of inductive learning, the belief that massed presentation is better than spaced presentation holds true even after people have taken a test and have done better with spacing! At the same time, other recent work (e.g., Benjamin & Bird, 2006; Toppino & Cohen, 2010) has found evidence that people do prefer later re-study to immediate re-study when allowed to choose between the two. Current work in the Bjork Learning and Forgetting Lab is examining further whether and in what contexts people are aware of the benefits of spaced practice when they are allowed to choose how to space repeated study opportunities. Back to Table of Contents
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