Effects of orienting task,spacing of repetitions,and list context on judgments of frequency

Subjects were given an unexpected frequency judgment test following a list of words in which items were presented either two, three, and five times or three, five, and seven times, with a spacing of 0, 2, 16, or 32 items between repetitions. During list presentation, they either rated the imagery value of each word or made continuous frequency estimates. Postlist frequency judgments of words presented three and five times were higher for the list containing words of Frequency 7, and judgments were also higher following the imagery rating task. Continuous judgments were unaffected by the list context and showed different effects of spacing than postlist judgments. The results provide support for the operation of response bias factors in the frequency judgment task and are relevant to theoretical interpretations of the spacing effect.     

Modeling the effects of repetitions, similarity, and normative word frequency on old-new recognition and judgments of frequency

Judgments of frequency for targets (old items) and foils (similar; dissimilar) steadily increase as the number of times a target is studied increases, but discrimination of targets from similar foils does not steadily improve, a phenomenon termed registration without learning (D. L. Hintzman & T. Curran, 1995; D. L. Hintzman, T. Curran, & B. Oppy, 1992). The present experiment explores this phenomenon with words of differing normative word frequency. The retrieving-effectively-from-memory model (REM; R. M. Shifrrin & M. Steyvers, 1997, 1998) predicts that low-frequency words will be better recognized than high-frequency words because low-frequency words have more distinctive memory representations. A corollary of this assumption predicts that the typical recognition word-frequency effect will be disrupted when similar foils are tested. These predictions were confirmed, but to fit both the recognition and the judgment-of-frequency data, the authors used a "dual-process" extension of the REM model.     

Encoding variability theory and the spacing effect in associate learning

Encoding variability theory accounts for the spacing effect by assuming that, as the lag between repetitions increases, the memorial representations approach independence. A method for testing this assumption in determining repetition effects in associative learning is suggested. In the independence hypothesis, we simply assume that each presentation of a word pair is represented independently, so that the expected proportion recalled is simple, P=P1+P2 - PIP2. Two studies are reported using a continuous paired-associate task representing a factorial combination of lag and retention interval as well as single-presentation control conditions. The results indicate that for moderately long retention intervals, as the lag between repetitions increases, the observed proportion recalled is first less, then eventually exceeds, and then returns to the level expected by an independence hypothesis.     

Encoding processes and the spacing effect

The differential encoding theory of the spacing effect was tested utilizing Martin's (1968) encoding variability notion, in which it is hypothesized that low-meaningfulness items are more variable in their encodings than are high-meaningfulness items. In a series of three experiments using a continuous paired associate learning task, it was predicted that the spacing vs. performance curves for CCC items would show a faster improvement in performance than would the curves for high-meaningfulness CVC items. None of the experiments supported this prediction. In addition, it was found that items recognized on their second presentation were more likely to be recalled than were those items not recognized. It was concluded that an item's repetitions are more effective if one code is formed and elaborated with each repetition rather than if more than one code is formed.     

Effects of level of processing and rehearsal on frequency judgments

The effects of attention during encoding and rehearsal after initial encoding on frequency estimates were investigated in three experiments. Varying the level of processing affected the linear increase in frequency estimates as a function of actual frequency, but varying processing after encoding with remember or forget cues had the greatest effects on the intercept of the function relating judged to actual frequency. Deeper levels of processing improved performance in a frequency discrimination task, whereas remember and forget cues had only very small effects on performance. Materials that are easy to rehearse were compared with materials that are difficult to rehearse in Experiment 2. The results were interpreted as evidence against a covert rehearsal explanation of slope effects in frequency estimation tasks because materials that are difficult to rehearse tended to produce larger interactions between remember versus forget cues and frequency than materials that are easier to rehearse. In Experiment 3, an arithmetic task that was performed during word encoding affected the slope of the function relating judged to actual frequency, but the same task performed immediately after word presentation had no effect on frequency estimates. It was concluded that frequency is not stored automatically because attention during the initial stages of encoding affects it; however, attention devoted to processing after initial encoding does not affect the rate with which subjective frequency increases with repetitions.     

Encoding richness of self-generated elaboration and spacing effects on incidental memory

The present study investigated encoding variability in self-generated elaboration on incidental memory as a function of the type of presentation which was either massed or spaced. The subjects generated different answers to a "why" question for the first and the second presentations of a target sentence in a self-generated elaboration condition. In an experimenter-provided elaboration condition they then rated the appropriateness of the different answers provided by the experimenter for the first and second presentations. This procedure was followed by two free recall tests, one of which was immediate and the other delayed. A self-generated elaboration effect was observed in both the spaced and the massed presentations. These results indicated that the self-generated elaboration effect was facilitated, even in the massed presentation because the different answers to the first and the second presentations led to a richer encoding of each target.     

The effects on priming of word frequency, number of repetitions, and delay depend on the magnitude of priming

Conflicting findings with respect to the effects of experimental manipulations on priming have been reported in previous studies. It is argued that, in many priming tasks, large amounts of task-relevant information are available from various sources, and that, therefore, the information available from a specific study episode will have only a small impact on overall performance level. Under such circumstances, high levels of baseline performance and small priming effects will be observed. The experiments reported here investigated the hypothesis that a high baseline performance in informationprocessing tasks that are used to measure priming may constrain priming effects. In a series of wordnaming experiments, perceptual difficulty and, therefore, baseline performance was manipulated. Under easy conditions, priming effects were relatively small and were not affected by word frequency, spaced repetition, or delay. Under more difficult conditions, priming effects were larger, and significant effects of all of the above-mentioned experimental manipulations were observed. Under conditions that produced the largest priming effects, a significant relationship between priming and explicit-memory performance could be observed. In the last experiment, it was shown that the characteristics of the retrieval task can substantially affect the magnitude of priming. It is argued that priming effects should be considered to reflect interactions between memory traces and the information-processing components of the priming task.     

Primacy and frequency effects in absolute judgments of visual velocity

In absolute judgment tasks, identical stimuli are rated higher (or lower) when presented in a series of more frequent small (or large) stimuli. Using visual stimuli differing in velocity, we show that this conventional frequency effect is largely modulated by the primacy effect--that is, by the stimuli occurring on the early trials of a run. In Experiment 1, a frequency-like primacy effect was obtained with equal-frequent velocities. Identical velocities were rated faster when mainly slow rather than fast ones occurred on initial trials. In Experiment 2, we contrasted the frequency effect and the primacy effect: In runs with frequent slow velocities, mainly fast ones occurred earlier, whereas in runs with infrequent slow velocities, mainly slow ones did so. Lack of differences of ratings in the two conditions suggests that the two effects canceled each other. In Experiment 3, when mainly frequent velocities occurred earlier, the conventional frequency effect was obtained. We conclude that the conventional frequency effect represents a combination of the primacy effect and the pure frequency effect.     

Similarity, global matching, and judgments of frequency

In the test-pair similarity effect, forced-choice recognition is more accurate for similar test pairs, such as leopard-cheetah, than it is for unrelated test pairs, such as leopard-turnip. According to global matching models, this occurs because the retrieved familiarities of similar items are correlated. In the Minerva 2 model, global matching underlies frequency judgments as well as recognition memory. One implication of this model is that judged frequencies of similar items should be correlated. Another implication is that judgments of summed frequency for pairs of words (how many presentations were there of word1 and word2 combined?) should have higher variance when word1 and word2 are similar than when they are unrelated. These predictions were tested and confirmed in two experiments. A review of these and other results suggests that theories of recognition memory should also be applicable to frequency-judgment tasks.     

The effect of spacing repetitions on the recognition memory of young children and adults

In Experiment 1, preschoolers, first graders, and third graders were presented a list of pictures that included twice-presented items separated by varying numbers of intervening items. Performance on a subsequent recognition test improved as the spacing between repetitions increased, but the effect of spacing did not interact reliably with grade level. In Experiment 2a, we replicated the spaced-repetition effect in young children and found a similar effect in college students. In Experiment 2b, we varied the conditions under which lists were presented to college students and again found a spacing function that was comparable to that of very young children. The results are consistent with the hypothesis that spaced-repetition effects in recognition are produced by fundamental memory mechanisms that are operational at a very early age and which undergo little change with development.     

Laterality effects, levels of processing, and stimulus properties

Two hypotheses of hemispheric specialization are discussed. The first stresses the importance of the kind of processing to which the stimulus is subjected, and the second stresses the importance of the nature of the stimulus. To test these hypotheses, four experiments were carried out. In Experiment 1 verbal material was employed in a same-different classification task, and an overall right visual field superiority was found. Experiment 2, in which verbal stimuli were subjected to visuospatial transformations (i.e. mental rotations), yielded no laterality effect. In Experiment 3 geometrical figures were employed in a classification task similar to that of Experiment 1, and an overall left visual field superiority was found. In Experiment 4 both verbal and geometric stimuli were employed. The results showed a significant interaction between field of presentation and nature of the stimulus and no interaction between field of presentation and level of processing.     

Metacognitive judgments of repetition and variability effects in natural concept learning: evidence for variability neglect

In four experiments, we examined the effects of repetitions and variability on the learning of bird families and metacognitive awareness of such effects. Of particular interest was the accuracy of, and bases for, predictions regarding classification of novel bird species, referred to as category learning judgments (CLJs). Participants studied birds in high repetitions and high variability conditions. These conditions differed in the number of presentations of each bird (repetitions) and the number of unique species from each family (variability). After study, participants made CLJs for each family and were then tested. Results from a classification test revealed repetition benefits for studied species and variability benefits for novel species. In contrast with performance, CLJs did not reflect the benefits of variability. Results showed that CLJs were susceptible to accessibility-based metacognitive illusions produced by additional repetitions of studied items.     

Antecedent frequency effects during the processing of pronouns

An eye-movement reading experiment investigated whether the ease with which pronouns are processed is affected by the lexical frequency of their antecedent. Reading times following pronouns with infrequent antecedents were faster than following pronouns with frequent antecedents. We argue that this is consistent with a saliency account, according to which infrequent antecedents are more salient than frequent antecedents. The results are not predicted by accounts which claim that readers access all or part of the lexical properties of the antecedent during the processing of pronouns.     

The effects of word frequency and similarity on recognition judgments: the role of recollection

K. J. Malmberg, J. Holden, and R. M. Shiffrin (2004) reported more false alarms for low- than high-frequency words when the foils were similar to the targets. According to the source of activation confusion (SAC) model of memory, that pattern is based on recollection of an underspecified episodic trace rather than the error-prone familiarity process. The authors tested the SAC account by varying whether participants were warned about the nature of similar foils and whether the recognition test required the discrimination. More false alarms for low-frequency similar items occurred only when participants were not warned at study about the subtle features to be discriminated later. The differential false-alarm rate by word frequency corresponded to the pattern of remember responses obtained when the test instructions did not ask for a subtle discrimination, supporting the SAC account that reversed false-alarm rates to similar foils are based on the recollection process.     

The effects of root frequency, word frequency, and length on the processing of prefixed English words during reading

Two experiments were performed to investigate the roles of root morpheme frequency and word frequency in the encoding of prefixed words in sentence context. Two alternative words, which were equated on other indices but differed with respect to either root morpheme frequency or word frequency, were embedded in the same sentence frame. In Experiment 1, there was a significant root morpheme frequency effect on gaze duration but only a marginal word frequency effect. Post hoc analyses indicated that word length influenced both effects, with word frequency effects predominating for shorter words and root morpheme effects predominating for longer words. In Experiment 2, word length was also manipulated. There was a significant root frequency effect for longer prefixed words and a significant word frequency effect for shorter prefixed words. The results were best explained by a dual-route model (with competing whole-word access and compositional routes), in which increasing word length inhibited the whole-word process, relative to the compositional route.     

Category size and judgments of variability: The effects of seeing the trees in the forest1

Abstract: Competing predictions about the effects of category size on judgments of category variability were examined in two studies involving the presentation of exemplars of two artificial social groups. In contrast to predictions of some exemplar-based models, Experiment 1 demonstrated that a numerically smaller group was perceived to be more variable than a larger group on the standard deviation measure of frequency distribution estimates. The result was interpreted to be an effect of differential information load. Experiment 2 revealed that variability judgments were influenced by prior expectations about the central tendencies as well as by practice in retrieving information about category exemplars. When frequency distribution estimates were made subsequent to abstract tasks, expectations about the numerical majority reduced perceived variability, while this influence was mitigated when memory measures preceded the frequency estimates.     

Word frequency and root-morpheme frequency effects on processing of Korean particle-suffixed words

Two experiments investigated the roles of the frequency of the root morpheme and the frequency of the whole word for a particular type of suffixed word in Korean in which the suffixed word can be thought of as a phrase (e.g., grandson-with). In both experiments, sentence frames were constructed so that they could have one of two target words that varied on frequency characteristics in the same location in the sentence. In Experiment 1, the frequency of the root morpheme was varied with the frequency of the word controlled, and in Experiment 2, the frequency of the word was varied with the frequency of the root morpheme controlled. Word frequency had a significant effect on fixation times, whereas root morpheme frequency did not. The results were surprising as native Korean speakers view the root morpheme as the “word” (analogous to how English readers would view a noun followed by a prepositional phrase).