Doug Rohrer

• Ph. D.
• Professor at University of South Florida

Many randomized controlled experiments in the classroom have found that mathematics learning is improved dramatically when practice problems of one kind are distributed across multiple assignments (spaced) and mixed with other kinds of problems (interleaved). In two studies, we investigated students' knowledge of spacing and interleaving. In Study...

The practice assignments in a mathematics textbook or course can be arranged so that most of the problems relating to any particular concept are massed together in a single assignment, or these related problems can be distributed across many assignments – a format known as spaced practice. Here we report the results of two classroom experiments tha...

A typical mathematics assignment consists of one or two dozen practice problems relating to the same skill or concept, yet empirical evidence suggests that there is little or no long-term benefit from working more than a few problems of the same kind in immediate succession. Alternatively, randomized experiments in the laboratory and classroom have...

A typical mathematics assignment consists of a block of problems devoted to the same topic, yet several classroom-based randomized controlled trials have found that students obtain higher test scores when most practice problems are mixed with different kinds of problems—a format known as interleaved practice. Interleaving prevents students from saf...

A highly cited article by Vohs, Mead, and Goode (2006) reported several experiments in which an incidental reminder of money produced large effects on subsequent behaviors unrelated to money. We attempted 2 high-powered direct replications of the first experiment, which found that money-primed subjects worked on a puzzle nearly twice as long as con...

We report the results of a preregistered, cluster randomized controlled trial of a mathematics learning intervention known as interleaved practice. Whereas most mathematics assignments consist of a block of problems devoted to the same skill or concept, an interleaved assignment is arranged so that no 2 consecutive problems require the same strateg...

A recent paper by Chatterjee, Rose, and Sinha (2013) reported impressively large “money priming” effects: incidental exposure to concepts relating to cash or credit cards made participants much less generous with their time and money (after cash primes) or much more generous (after credit card primes ). Primes also altered participants’ choices in...

A number of researchers have reported studies showing that subtle reminders of money can alter behaviors and beliefs that are seemingly unrelated to money. In 1 set of studies published in this journal, Caruso, Vohs, Baxter, and Waytz (2013) found that incidental exposures to money led subjects to indicate greater support for inequality, socioecono...

In many academic courses, students encounter a particular fact or concept many times over a period of a few weeks and then do not see it again during the remainder of the course. Are these brief instructional periods sufficient, or should the same amount of instruction be distributed over longer periods of time? This question was the focus of sever...

Retrieval practice has been shown to enhance later recall of information reviewed through testing, whereas final-test measures involving making inferences from the learned information have produced mixed results. In four experiments, we examined whether the benefits of retrieval practice could transfer to deductive inferences. Participants studied...

Most mathematics assignments consist of a group of problems requiring the same strategy. For example, a lesson on the quadratic formula is typically followed by a block of problems requiring students to use that formula, which means that students know the appropriate strategy before they read each problem. In an alternative approach, different kind...

A typical mathematics assignment consists primarily of practice problems requiring the strategy introduced in the immediately preceding lesson (e.g., a dozen problems that are solved by using the Pythagorean theorem). This means that students know which strategy is needed to solve each problem before they read the problem. In an alternative approac...

In a simple study involving 64 participants, Rasinski, Visser, Zagatsky, and Rickett (2005) reported that requiring people to make semantic judgments involving four words related to honesty (embedded among other words) increased the likelihood that they would later admit to having engaged in problematic alcohol-related behaviors (e.g., drinking to...

Bargh et al. (2001) reported two experiments in which people were exposed to words related to achievement (e.g., strive, attain) or to neutral words, and then performed a demanding cognitive task. Performance on the task was enhanced after exposure to the achievement related words. Bargh and colleagues concluded that better performance was due to t...

Every day, students and instructors are faced with the decision of when to study information. The timing of study, and how it affects memory retention, has been explored for many years in research on human learning. This research has shown that performance on final tests of learning is improved if multiple study sessions are separated—i.e., “spaced...

When students encounter a set of concepts (or terms or principles) that are similar in some way, they often confuse one with another. For instance, they might mistake one word for another word with a similar spelling (e.g., allusion instead of illusion) or choose the wrong strategy for a mathematics problem because it resembles a different kind of...

Taking a test has been shown to produce enhanced retention of the retrieved information. On tests, however, students often encounter questions the answers for which they are unsure. Should they guess anyway, even if they are likely to answer incorrectly? Or are errors engrained, impairing subsequent learning of the correct answer? We sought to answ...

Previous research shows that interleaving rather than blocking practice of different skills (e.g. abcbcacab instead of aaabbbccc) usually improves subsequent test performance. Yet interleaving, but not blocking, ensures that practice of any particular skill is distributed, or spaced, because any two opportunities to practice the same task are not c...

There has been a recent upsurge of interest in exploring how choices of methods and timing of instruction affect the rate and persistence of learning. The authors review three lines of experimentation—all conducted using educationally relevant materials and time intervals— that call into question important aspects of common instructional practices....

Numerous learning studies have shown that if the period of time devoted to studying information (e.g., casa-house) includes at least 1 test (casa-?), performance on a final test is improved-a finding known as the testing effect. In most of these studies, however, the final test is identical to the initial test. If the final test requires a novel de...

The spacing of a fixed amount of study time across multiple sessions usually increases subsequent test performance—a finding known as the spacing effect. In the spacing experiment reported here, subjects completed multiple learning trials, and each included a study phase and a test. Once a subject achieved a perfect test, the remaining learning tri...

More than a century of research shows that increasing the gap between study episodes using the same material can enhance retention, yet little is known about how this so-called distributed practice effect unfolds over nontrivial periods. In two three-session laboratory studies, we examined the effects of gap on retention of foreign vocabulary, fact...

Sets of mathematics problems are generally arranged in 1 of 2 ways. With blocked practice, all problems are drawn from the preceding lesson. With mixed review, students encounter a mixture of problems drawn from different lessons. Mixed review has 2 features that distinguish it from blocked practice: Practice problems on the same topic are distribu...

The term “learning styles” refers to the concept that individuals differ in regard to what mode of instruction or study is most effective for them. Proponents of learning-style assessment contend that optimal instruction requires diagnosing individuals' learning style and tailoring instruction accordingly. Assessments of learning style typically as...

To achieve enduring retention, people must usually study information on multiple occasions. How does the timing of study events affect retention? Prior research has examined this issue only in a spotty fashion, usually with very short time intervals. In a study aimed at characterizing spacing effects over significant durations, more than 1,350 indi...

In most mathematics textbooks, each set of practice problems is comprised almost entirely of problems corresponding to the immediately previous lesson. By contrast, in a small number of textbooks, the practice problems are systematically shuffled so that each practice set includes a variety of problems drawn from many previous lessons. The standard...

Because people forget much of what they learn, students could benefit from learning strategies that provide long-lasting knowledge. Yet surprisingly little is known about how long-term retention is most efficiently achieved. Here we examine how retention is affected by two variables: the duration of a study session and the temporal distribution of...

Our research on learning enhancement has been focusing on the consequences for learning and forgetting of some of the more obvious and concrete choices that arise in instruction, including questions such as these: How does spacing of practice affect retention of information over significant retention intervals (up to 1 year)? Do spacing effects gen...

In two experiments, 216 college students learned to solve one kind of mathematics problem before completing one of various practise schedules. In Experiment 1, students either massed 10 problems in a single session or distributed these 10 problems across two sessions separated by 1 week. The benefit of distributed practise was nil among students wh...

The authors performed a meta-analysis of the distributed practice effect to illuminate the effects of temporal variables that have been neglected in previous reviews. This review found 839 assessments of distributed practice in 317 experiments located in 184 articles. Effects of spacing (consecutive massed presentations vs. spaced learning episodes...

Once material has been learned to a criterion of one perfect trial, further study within the same session constitutes overlearning. Although overlearning is a popular learning strategy, its effect on long-term retention is unclear. In two experiments presented here, 218 college students learned geography facts (Experiment 1) or word definitions (Ex...

Some researchers have suggested that although feedback may enhance performance during associative learning, it does so at the expense of later retention. To examine this issue, subjects (N = 258) learned Luganda-English word pairs. After 2 initial exposures to the materials, subjects were tested on each item several times, with the presence and typ...

In three experiments, college students provided judgments about a marble's speed along a nonlinear incline. Each experiment revealed widespread support for the slope-speed belief, a mistaken belief holding that an object's speed at any point depends on the slope at that point. In truth, an object's incline speed varies with its elevation. In Experi...

Previous studies combining continuous free recall with a concurrent task have generally shown that concurrent tasks impose fairly negligible effects on memory retrieval. By contrast, dual-task studies employing either cued recall or semantic retrieval reveal gross memory impairment and suggest that retrieval is delayed by the centrally demanding ph...

In 3 experiments, college students provided qualitative predictions about a marble's speed along nonlinear inclines. When predicting the outcome of a race between identical marbles along differently shaped ramps, most students predicted incorrectly that the shorter path was necessarily quicker (the shorter-quicker belief). When comparing instantane...

The recall of previously studied items is widely believed to incorporate a search of a markedly constrained set of possibilities, and the present study examines whether this set of items typically includes unstudied semantic associates of the study items. In an episodic task, participants recalled a previously studied list of eight exemplars drawn...

Alzheimer's disease (AD) and Huntington's disease (HD) impair performance on semantic memory tasks, but researchers disagree on whether AD and HD cause these impairments in the same manner. According to one view, AD disrupts the storage of semantic memories, whereas HD disrupts the retrieval of semantic memories. Dissenters argue that AD, like HD,...

We examined whether two memories can be retrieved concurrently from long-term memory. In Experiment 1, the subjects recalled words, either from two categories--alternating between the two--or from just one category. In Experiment 2, the subjects recalled two words belonging to either the same category or different categories, and the category promp...

Subjects studied either an 8- or 16-word list and later recalled the items while a voice key recorded each response latency. The trials were partitioned by recall total in order to examine the means and distributions of both latencies and interresponse times as a function of recall total. Each analysis was consistent with the view that an item's ab...

In 3 experiments, participants generated category exemplars (e.g., kinds of fruits) while a voice key and computer recorded each response latency relative to the onset of responding. In Experiment 1, mean response latency was faster when participants generated exemplars from smaller categories, suggesting that smaller mental search sets result in f...

In 3 experiments, participants generated category exemplars (e.g., kinds of fruits) while a voice key and computer recorded each response latency relative to the onset of responding. In Experiment 1, mean response latency was faster when participants generated exemplars from smaller categories, suggesting that smaller mental search sets result in f...

In four experiments, subjects freely recalled previously studied items while a voice key and computer recorded each item's recall latency relative to the onset of the recall period. The measures of recall probability and mean recall latency were shown to be empirically independent, demonstrating that there exists no a priori relationship between th...

Relatively few experiments have measured the time course of free recall from episodic or semantic memory. Of those that have, most report that cumulative recall is a negatively accelerated exponential (or hyperbolic) function that is characterized by two properties: asymptotic recall and rate of approach to asymptote. The most common measure of fre...

Proactive interference (PI) has long been recognized as a major cause of forgetting. Two experiments were conducted that offer another look at the subject by providing a detailed analysis of recall latency distributions during the buildup of and release from PI. These functions were accurately characterized by the convolution of the normal and expo...

Proactive interference (PI) has long been recognized as a major cause of forgetting. We conducted two experiments that offer another look at the subject by providing a detailed analysis of recall latency distributions during the buildup of and release from PI. These functions were accurately characterized by the convolution of the normal and expone...

In demonstrations of part-list cuing inhibition, subjects who are shown a subset of studied list words recall fewer noncue words than subjects not shown such part-list cues. We propose that part-list inhibition is governed in part by an incongruency principle: Inhibition occurs to the extent that part-list cues induce a retrieval framework differen...

In demonstrations of part-list cuing inhibition, subjects who are shown a subset of studied list words recall fewer noncue words than subjects not shown such part-list cues. We propose that part-list inhibition is governed in part by an incongruency principle: Inhibition occurs to the extent that part-list cues induce a retrieval framework differen...