Surface form and the spacing effect

Deficient processing theories of the spacing effect attribute poor recall of massed-repeated items to a failure to process one or both of the presentations fully. An implication of this approach is that anything that increases the probability that a repetition will receive full processing, or conversely, anything that decreases the probability that the item will be recognized as a repetition, should improve memorability of the item. The present set of experiments tested this prediction by manipulating the surface structure of repeated sentences. On the basis of previous research, it was assumed that memory for surface structure of sentences decays rapidly, and hence can contribute to initial identification of repetitions only at short spacings. Because this manipulation should hinder recognition of repetitions as repetitions, it was expected to induce full processing of massed repetitions, and thus facilitate recall of these items. This prediction was supported. When sentences were repeated verbatim (Experiment 1) or by the same speaker (Experiment 2), the typical spacing effect was obtained. However, when the surface structure or speaker changed at time of repetition, massed repetitions were recalled nearly as well (Experiment 1) or as well (Experiment 2) as their spaced counterparts.     

Pupil dilations following pairs of identical and related to-be-remembered words

Two experiments are reported in which the spacing between pairs of identical (Experiment 1) or pairs of related (Experiment 2) to-be-remembered words were varied while pupil diameter and frequency judgments were measured. In Experiment 1, frequency judgments increased with increases in spacing length. In Experiment 2, frequency judgments decreased with increases in spacing length. In both experiments, however, pupil dilations increased with increases in spacing length. These results are interpreted as supporting theories that argue that massed repetitions require less processing than spaced repetitions. It is argued that this deficiency in processing reduces retention of massed repetitions of identical words. For massed presentation of related words, organizational strategies can be used with little effort to increase retention.     

Encoding, maintenance, and retrieval processes in the lag effect: a multinomial processing tree analysis

Short-term studies on repeated learning of verbatim material have typically revealed an overall benefit of long lags compared to short lags between repetitions. This has been referred to as the lag effect. On educationally relevant time scales, however, an inverted-U-shaped relation between lag and memory performance is often observed. Recently, Cepeda et al. (2009) showed that the optimal lag for relearning depends heavily on the time interval between the last learning session and the final memory test (i.e., the retention interval; RI). In order to explore the cognitive mechanisms underlying this result in more detail we independently manipulated both the lag and the RI in a 3×2 experimental design and analysed our data using a multinomial processing tree model for free-then-cued-recall data. Our results reveal that the lag effect trends are mainly driven by encoding and maintenance processes rather than by retrieval mechanisms. Our findings have important implications for theories of the lag effect.     

Book review

In two experiments, participants were asked to perform simple action statements or to imagine performing the actions one, two, or four times in a single study session. The lag between repetitions could vary from 5 to 10 intervening items in Experiment 1 or be fixed at 0 and 4 in Experiment 2. In a test session that occurred either 24 or 48 hours later, participants were instructed to recognise statements only if they had occurred during the first session and, if recognised, to tell whether the action statement had been carried out or imagined. The primary finding was that it is possible to obtain an imagination inflation effect (that is, as repeated imaginations increase, participants are more likely to remember an action as performed) using a within-list paradigm. However, this outcome occurred only for spaced repetitions. The results are consistent with the hypothesis that repeated imagination increases the level of familiarity, which may, in turn, generate this memory illusion.     

The "one-shot" hypothesis for context storage

In 3 experiments motivated by the implicit memory literature, the authors investigated the effects of different strengthening operations on the list strength effect (LSE) for explicit free recall, an effect posited by R. M. Shiffrin, R. Ratcliff, and S. E. Clark (1990) to be due to context cuing. According to the one-shot hypothesis, a fixed amount of context is stored when an item is studied for at least 1 or 2 s. Beyond the initial context storage, increases in study time or different orienting tasks do not influence the amount of context that is stored, and thus only spaced repetitions should produce a positive LSE. Consistent with prior findings, spaced repetitions always produced a positive LSE, but increases in depth of processing, study time, and massed repetitions did not. A model implements the one-shot hypothesis, and a role for context storage as a link between episodic and semantic memory is discussed.     

Spacing repetitions over 1 week

Does varying the spacing of repetitions over intervals as long as 1 week aftect recall? The answer from three experiments is yes. Subjects incidentally processed words repeated within a single list and words repeated in separate lists at list spacings of up to 1 week. Memory was tested by free recall shortly after the second presentations or after retention intervals of up to 1 week. Recall of the words repeated across separate lists conformed to a proportionality rule. When the retention interval is short relative to the spacing intervals, performance is inversely related to spacing. When the retention interval is a large proportion of the spacing intervals, performance is directly related to spacing. Does varying the spacing of repetitions within a single list affect recall after a retention interval of 2 weeks? The answer depends on the processing used while studying the words. Processing that generated interitem associations resulted in a within-list spacing effect even after a 2-week retention interval. Without the interitem associations, the effect was absent after a 1-day retention interval. Most of these findings were explained by examining the changing relationship between the retrieval context and the context stored during study.     

Adult age differences in memory for massed and distributed repeated actions

Adult age differences in memory for actions were investigated in 2 experiments in which actions were repeated with massed or distributed spacing. In Experiment 1, subjects received a mixed series of actions, half performed once, the others twice, with repetitions either massed or distributed. Young subjects recalled more actions than did the elderly, and more distributed actions were recalled than massed actions. However, the Age X Spacing interaction was not significant. A probable inhibitory mechanism with a mixed list was avoided in Experiment 2 by use of unmixed series. Actions were performed once only, twice only in massed repetitions, or twice only in distributed repetitions. The age difference was significant, and more actions were recalled in the distributed condition than in either of the other conditions, the results of which did not differ from one another. The Age X Conditions interaction was negligible. These results imply that elderly subjects are as likely as young subjects to encode contextual information while performing actions.     

NOTE ON THE RETENTION OF CONNECTED DISCOURSE

Two sentences were constructed having roughly the same content but different predictability ( P -) scores. One or other of the sentences was presented auditorily once only to different groups of subjects who were instructed to listen carefully, without however, being informed of the learning character of the experiment. The groups were then tested for retention after one of the following intervals: IM, 3 min., 2 hours, 20 hours. The sentences were found to differ in memorability (amount recalled) in IM but not in LTM. The reproductions were also analysed with regard to synonym and non-synonym substitutions and the implications for the chunking hypothesis discussed.     

Nonstrategic contributions to putatively strategic effects in selective attention tasks

Proportion compatible manipulations are often used to index strategic processes in selective attention tasks. Here, a subtle confound in proportion compatible manipulations is considered. Specifically, as the proportion of compatible trials increases, the ratio of complete repetitions and complete alternations to partial repetitions increases on compatible trials but decreases on incompatible trials. This confound is demonstrated to lead to an overestimation in the magnitude of the proportion compatible effect in the context of both a Stroop and a Simon task. Implications for previous research and directions for future research using proportion compatible manipulations are discussed.     

Total time and efficient time management: in search of optimal learning and retention via study-test-rest presentation programs

Bugelski's total time hypothesis (TTH) assumes that a constant time X is needed to learn Y regardless of how time X is programmed, with no possibility of optimization. Izawa's study-test-rest (STR) hypothesis assumes that optimization in learning and retention is possible. Examined were the effects of varied study (S) and test (T) presentation programs on learning and retention, with total time held constant. Participants learned a list of 12 paired associates under three presentation program types. In S + T list repetitions, each pair was presented once per S cycle and tested once per T cycle; both S and T were repeated in list form. In S + T item repetitions, each pair was repeated 1-6 times before the next pair in the list was presented on both S and T cycles. For S/T alternations, the entire list of pairs was studied and then each pair was tested, with S and T cycles alternating. Under each program type, there were four presentation rates. Item repetition led to more learning than list repetition when the presentation rate was very fast. Learning and retention were greatest with the intermediate S/T alternation program. These findings supported Izawa's STR hypothesis but strongly contradicted TTH.     

Forgetting curves: implications for connectionist models

Forgetting in long-term memory, as measured in a recall or a recognition test, is faster for items encoded more recently than for items encoded earlier. Data on forgetting curves fit a power function well. In contrast, many connectionist models predict either exponential decay or completely flat forgetting curves. This paper suggests a connectionist model to account for power-function forgetting curves by using bounded weights and by generating the learning rates from a monotonically decreasing function. The bounded weights introduce exponential forgetting in each weight and a power-function forgetting results when weights with different learning rates are averaged. It is argued that these assumptions are biologically reasonable. Therefore power-function forgetting curves are a property that may be expected from biological networks. The model has an analytic solution, which is a good approximation of a power function displaced one lag in time. This function fits better than any of the 105 suggested two-parameter forgetting-curve functions when tested on the most precise recognition memory data set collected by. Unlike the power-function normally used, the suggested function is defined at lag zero. Several functions for generating learning rates with a finite integral yield power-function forgetting curves; however, the type of function influences the rate of forgetting. It is shown that power-function forgetting curves cannot be accounted for by variability in performance between subjects because it requires a distribution of performance that is not found in empirical data. An extension of the model accounts for intersecting forgetting curves found in massed and spaced repetitions. The model can also be extended to account for a faster forgetting rate in item recognition (IR) compared to associative recognition in short but not long retention intervals.     

EFFECT OF STRUCTURAL CUEING AND DECISION TYPE FOR IMPROVING RETENTION OF TECHNICAL TEXT

This study investigated the effects of structural cueing (color or no color) and decision level (rote or semantic) on students' verbatim retention of technical prose. Structural cueing represented the assimilation of encoding hypothesis for improving memory, and decision tasks represented the distinctiveness of encoding hypothesis for promoting deep processing. Subjects read an article on a microcomputer monitor in which either color‐coding or white‐only print was used to represent the structural importance among ideas in each paragraph and then, subsequent to each paragraph, responded to either rote memory or semantic memory decision statements. Results of a free written recall measure using a two‐factor analysis of covariance, revealed significant differences between students' retention on decision type but no differences based on color cueing. That is, students who responded to semantic level decision statements recalled more of the text than those who responded to the rote level decision statements. The results supported the distinctiveness of encoding hypothesis for learning via the microcomputer but did not support the assimilation of encoding hypothesis.     

Probability matching, accuracy maximization, and a test of the optimal classifier’s independence assumption in perceptual categorization

Observers completed perceptual categorization tasks that included 25 base-rate/payoff conditions constructed from the factorial combination of five base-rate ratios (1:3, 1:2, 1:1, 2:1, and 3:1) with five payoff ratios (1:3, 1:2, 1:1, 2:1, and 3:1). This large database allowed an initial comparison of the competition between reward and accuracy maximization (COBRA) hypothesis with a competition between reward maximization and probability matching (COBRM) hypothesis, and an extensive and critical comparison of the flat-maxima hypothesis with the independence assumption of the optimal classifier. Model-based instantiations of the COBRA and COBRM hypotheses provided good accounts of the data, but there was a consistent advantage for the COBRM instantiation early in learning and for the COBRA instantiation later in learning. This pattern held in the present study and in a reanalysis of Bohil and Maddox (2003). Strong support was obtained for the flat-maxima hypothesis over the independence assumption, especially as the observers gained experience with the task. Model parameters indicated that observers’ reward-maximizing decision criterion rapidly approaches the optimal value and that more weight is placed on accuracy maximization in separate base-rate/payoff conditions than in simultaneous base-rate/payoff conditions. The superiority of the flat-maxima hypothesis suggests that violations of the independence assumption are to be expected, and are well captured by the flat-maxima hypothesis, with no need for any additional assumptions.     

Probability matching, accuracy maximization, and a test of the optimal classifier's independence assumption in perceptual categorization

Observers completed perceptual categorization tasks that included 25 base-rate/payoff conditions constructed from the factorial combination of five base-rate ratios (1:3, 1:2, 1:1, 2:1, and 3:1) with five payoff ratios (1:3, 1:2, 1:1, 2:1, and 3:1). This large database allowed an initial comparison of the competition between reward and accuracy maximization (COBRA) hypothesis with a competition between reward maximization and probability matching (COBRM) hypothesis, and an extensive and critical comparison of the flat-maxima hypothesis with the independence assumption of the optimal classifier. Model-based instantiations of the COBRA and COBRM hypotheses provided good accounts of the data, but there was a consistent advantage for the COBRM instantiation early in learning and for the COBRA instantiation later in learning. This pattern held in the present study and in a reanalysis of Bohil and Maddox (2003). Strong support was obtained for the flat-maxima hypothesis over the independence assumption, especially as the observers gained experience with the task. Model parameters indicated that observers' reward-maximizing decision criterion rapidly approaches the optimal value and that more weight is placed on accuracy maximization in separate base-rate/payoff conditions than in simultaneous base-rate/payoff conditions. The superiority of the flat-maxima hypothesis suggests that violations of the independence assumption are to be expected, and are well captured by the flat-maxima hypothesis, with no need for any additional assumptions.     

Pauses in elementary school children's verbatim and gist free recall of a story

The aim of the research was to explore the function of pauses in children's oral verbatim and gist-based free recall, assuming that pauses indicate cognitive processing. The main question guiding this research was whether verbatim and gist recall constituted two different ways of cognitive processing associated with different time patterns of speech. Elementary school children (n = 180) between the ages of 8 and 10 years heard a story and were then instructed to either retell the story verbatim or retell its gist. They orally recalled the story for the first time immediately after hearing the story and again 1 week later. The results confirmed the main hypothesis of independence of verbatim and gist traces in that mean pause lengths were longer when verbatim retrieval was asked for as compared to gist retrieval. High correct gist recall was characterized by more and shorter pauses, indicating fluent retrieval.     

Relationship between affect and memory: motivation-based selective generation.

Two experiments examined the influence of anger and retaliatory motivation on memory for negative material. In the 1st study, 60 male undergraduates memorized words with positive, negative, and neutral semantic connotations. It was found that angered men who expected to retaliate against their provocateur recalled more negative words than other words, and more than Ss in all other affect and evaluation conditions. Angered men in the nonretaliation condition displayed no differences in negative word recall. The 2nd experiment investigated memory for details of a provoking experience. Angered men who expected to retaliate more accurately recalled the details of their provocation, but whether they were given the retaliation information before or after provocation had no bearing on memory for these details. Results are discussed in terms of a motivation-based selective generation hypothesis for the relationship between anger and memory.     

A test of the optimal classifier’s independence assumption in perceptual categorization

Observers completed perceptual categorization tasks that included separate base-rate/payoff manipulations, corresponding simultaneous base-rate/payoff manipulations, and conflicting simultaneous base-rate/payoff manipulations. Performance (1) was closer to optimal for 2:1 than for 3:1 baserate/ payoff ratios and when base rates as opposed to payoffs were manipulated, and (2) was more in line with the predictions from the flat-maxima hypothesis than from the independence assumption of the optimal classifier in corresponding and conflicting simultaneous base-rate/payoff conditions. A hybrid model that instantiated simultaneously the flat-maxima and the competition between reward and accuracy maximization (COBRA) hypotheses was applied to the data. The hybrid model was superior to a model that incorporated the independence assumption, suggesting that violations of the independence assumption are to be expected and are well captured by the flat-maxima hypothesis without requiring any additional assumptions. The parameters indicated that observers’ reward-maximizing decision criterion rapidly approaches the optimal value and that more weight is placed on accuracy maximization in separate and corresponding simultaneous base-rate/payoff conditions than in conflicting simultaneous base-rate/payoff conditions.     

A test of the optimal classifier's independence assumption in perceptual categorization

Observers completed perceptual categorization tasks that included separate base-rate/payoff manipulations, corresponding simultaneous base-rate/payoff manipulations, and conflicting simultaneous base-rate/payoff manipulations. Performance (1) was closer to optimal for 2:1 than for 3:1 base-rate/payoff ratios and when base rates as opposed to payoffs were manipulated, and (2) was more in line with the predictions from the flat-maxima hypothesis than from the independence assumption of the optimal classifier in corresponding and conflicting simultaneous base-rate/payoff conditions. A hybrid model that instantiated simultaneously the flat-maxima and the competition between reward and accuracy maximization (COBRA) hypotheses was applied to the data. The hybrid model was superior to a model that incorporated the independence assumption, suggesting that violations of the independence assumption are to be expected and are well captured by the flat-maxima hypothesis without requiring any additional assumptions. The parameters indicated that observers' reward-maximizing decision criterion rapidly approaches the optimal value and that more weight is placed on accuracy maximization in separate and corresponding simultaneous base-rate/payoff conditions than in conflicting simultaneous base-rate/payoff conditions.