How many memory systems? Evidence from aging

The present research tested Tulving's (1985) ternary memory theory. Young (ages 19-32) and older (ages 63-80) adults were given procedural, semantic, and episodic memory tasks. Repetition, lag, and codability were manipulated in a picture-naming task, followed by incidental memory tests. Relative to young adults, older adults exhibited lower levels of recall and recognition, but these episodic measures increased similarly as a function of lag and repetition in both age groups. No age-related deficits emerged in either semantic memory (vocabulary, latency slopes, naming errors, and tip-of-the-tongue responses) or procedural memory (repetition priming magnitude and rate of decline). In addition to the age by memory task dissociations, the manipulation of codability produced slower naming latencies and more naming errors (semantic memory), yet promoted better recall and recognition (episodic memory). Finally, a factor analysis of 11 memory measures revealed three distinct factors, providing additional support for a tripartite memory model.     

Two effects of repetition: Support for a dual-process model of know judgments and exclusion errors

In three experiments, aremember/know recognition test (Experiments 1–2) and an exclusion test (Experiments 2–3) were used to examine effects of repeated study presentations. An effect of study repetition was obtained for remember but not know judgments, similar to results reported by Gardiner, Kaminska, Dixon, and Java (1996). Experiment 2 demonstrated the similarity between know responses and exclusion errors; neither was affected by repeated study presentations. In Experiment 3, a response deadline procedure was used to show that exclusion errors are the product of two opposing processes—recollection and familiarity—both of which are influenced by repetition. The interpretation of exclusion errors and know responses is shown to require a dual-process model that includes an assumption about the relationship between processes.     

Orientation invariance in visual object priming depends on prime—target asynchrony

Two experiments are reported in which orientation effects on visual object recognition latency were examined. In Experiment 1, we assessed picture-naming performance as a function of image-plane stimulus orientation and found increasing response times with increased misorientation of the stimulus. In Experiment 2, we examined the repetition priming effect on the identification of upright targets as a function of prime orientation. With time delays of 100, 200, or 500 msec between the onset of the prime and that of the target (i.e., stimulus onset asynchrony [SOA]), the magnitude of the priming effect decreased with increasing misorientation of the prime. These results contrast with the orientationinvariant priming effects reported in some previous repetition priming studies. These investigations all used relatively long prime—target SOAs. Confirming the crucial role of the latter variable, Experiment 2 shows that the magnitude of the repetition priming effect is invariant across prime orientations with an SOA of 1,000 msec. The possible implications of the present observations with respect to the issue of orientation invariance versus dependency of the visual object recognition process are discussed.     

Orientation invariance in visual object priming depends on prime-target asynchrony

Two experiments are reported in which orientation effects on visual object recognition latency were examined. In Experiment 1, we assessed picture-naming performance as a function of image-plane stimulus orientation and found increasing response times with increased misorientation of the stimulus. In Experiment 2, we examined the repetition priming effect on the identification of upright targets as a function of prime orientation. With time delays of 100, 200, or 500 msec between the onset of the prime and that of the target (i.e., stimulus onset asynchrony [SOA]), the magnitude of the priming effect decreased with increasing misorientation of the prime. These results contrast with the orientation-invariant priming effects reported in some previous repetition priming studies. These investigations all used relatively long prime-target SOAs. Confirming the crucial role of the latter variable, Experiment 2 shows that the magnitude of the repetition priming effect is invariant across prime orientations with an SOA of 1,000 msec. The possible implications of the present observations with respect to the issue of orientation invariance versus dependency of the visual object recognition processare discussed.     

The word frequency effect in recognition memory versus repetition priming

The role of word frequency in recognition memory and repetition priming was investigated by using a manipulation of attention. In Experiment 1, the lexical decision task produced greater repetition priming for low-frequency words than for high-frequency words following either the attended or the unattended study condition. The recognition memory test, on the other hand, showed a low-frequency word advantage only following the attended study condition. Furthermore, this advantage was limited to the measure of recognition memory based on conscious recollection of the study episode. In Experiment 2, a speeded recognition memory test replicated the pattern obtained with the unspeeded recognition memory test in Experiment 1. These results argue against the view that the word frequency effects in recognition memory and repetition priming have the same origin. Instead, the results suggest that the word frequency effect in recognition memory has its locus in conscious recollection.     

Examining the contributions of desirable difficulty and reminding to the spacing effect

Although substantial evidence indicates that spacing repeated study events with intervening material generally enhances memory performance relative to massing study events, the mechanism underlying this benefit is less clear. Two experiments examined the role of reminding difficulty during the acquisition of material in modulating final memory performance for spaced repetitions utilizing recognition (Experiment 1) and recall tests (Experiment 2). Specifically, participants studied a list of words presented one or two times separated by one or five items. On each trial participants reported whether the item had been previously presented (i.e., repetition detection judgment), and the response latency served as a proxy for reminding difficulty such that longer response latencies reflected more difficult reminding. A third experiment extended this paradigm with the inclusion of a massed condition and novel lag conditions (three and ten items). Results revealed significant lag effects in final test performance across experiments despite comparable repetition detection difficulty between lag conditions during acquisition. Moreover, results from within-participant point-biserial analyses and mediation analyses converged on overall performance measures in suggesting that repetition detection difficulty failed to modulate final test performance in the current paradigm. Discussion considers the implications of the current results for mechanisms proposed to underlie the benefits of spaced study and spaced retrieval practice.     

Memory search following valid and invalid abrupt-onset cues

The impact of abrupt-onset cues on memory search was investigated, where the abrupt-onset cue was a valid (Experiment 1), random (Experiment 2), or irrelevant (Experiment 3) predictor of the location containing the test probe. In Experiment 4, the abrupt-onset cue either preceded or followed the test probe. Sternberg-like functions were obtained in Experiments 1 and 2, with the effects of the abrupt-onset cue localized primarily in the intercept rather than the slope. Experiment 3 demonstrated that a spatially separated and irrelevant abrupt-onset cue increased latency even when all memory probes occurred at the fixation point. In Experiment 4, the robust impact of an abrupt-onset cue vanished, regardless of stimulus onset asynchrony, when it followed the target. We concluded that abrupt-onset cues captured attention regardless of their predictability, manifested as a delaying of search. However, once attention was captured by the target, a subsequent abrupt-onset stimulus had no effect. These results were discussed in terms of diffuse attention and contingent capture models of attention.     

Dependent processing in dichotic listening as a function of word meaning attributes

Single dichotic word pairs were presented for immediate identification. Recognition probability was greater and response latencies shorter for high- than for low-frequency words. Both recognition measures were also affected by the frequency of the word accompanying the target word, performance being facilitated by a high-frequency partner and sometimes impaired by a low-frequency partner. Associative meaningfulness had similar, though less reliable, effects whereas the effects of word concreteness-abstractness were inconsistent. Recognition accuracy was generally superior for right-ear inputs, but recognition latency did not show consistent ear effects. Similar results were obtained under both unrestricted (Experiment 1) and controlled (Experiment 2) ear order of report instructions. The findings are consistent with a limited capacity interpretation of secondary processing in word perception.     

On the joint effects of repetition and stimulus quality in lexical decision: Looking to the past for a new way forward

Two experiments investigated the joint effects of stimulus quality and repetition in the context of lexical decision. Experiment 1 yielded an interaction between repetition and stimulus quality for words (but additive effects for nonwords) when the lag was short, replicating previous reports. Experiment 2, with a much longer lag than Experiment 1, yielded main effects of stimulus quality and repetition, but these factors no longer interact. The joint effects of stimulus quality and repetition for words as a function of lag can be understood in terms of two loci for repetition effects: one short-term and one long-term. The transient effect of repetition is on activation levels in the lexicons (and in which the input lexicon, but not beyond, is affected by stimulus quality), whereas the long-term effect is on the strength of two-way connections between lexical–lexical and lexical–semantic modules. These data and others, taken together with the account, provide a new way of thinking about a 30-year-old conundrum.     

On the joint effects of repetition and stimulus quality in lexical decision: looking to the past for a new way forward

Two experiments investigated the joint effects of stimulus quality and repetition in the context of lexical decision. Experiment 1 yielded an interaction between repetition and stimulus quality for words (but additive effects for nonwords) when the lag was short, replicating previous reports. Experiment 2, with a much longer lag than Experiment 1, yielded main effects of stimulus quality and repetition, but these factors no longer interact. The joint effects of stimulus quality and repetition for words as a function of lag can be understood in terms of two loci for repetition effects: one short-term and one long-term. The transient effect of repetition is on activation levels in the lexicons (and in which the input lexicon, but not beyond, is affected by stimulus quality), whereas the long-term effect is on the strength of two-way connections between lexical-lexical and lexical-semantic modules. These data and others, taken together with the account, provide a new way of thinking about a 30-year-old conundrum.     

Effects of repetition priming on recognition memory: testing a perceptual fluency-disfluency model

Five experiments explored the effects of immediate repetition priming on episodic recognition (the "Jacoby-Whitehouse effect") as measured with forced-choice testing. These experiments confirmed key predictions of a model adapted from D. E. Huber and R. C. O'Reilly's (2003) dynamic neural network of perception. In this model, short prime durations pre-activate primed items, enhancing perceptual fluency and familiarity, whereas long prime durations result in habituation, causing perceptual disfluency and less familiarity. Short duration primes produced a recognition preference for primed words (Experiments 1, 2, and 5), whereas long duration primes produced a preference against primed words (Experiments 3, 4, and 5). Experiment 2 found prime duration effects even when participants accurately identified short duration primes. A cued-recall task included in Experiments 3, 4, and 5 found priming effects only for recognition trials that were followed by cued-recall failure. These results suggest that priming can enhance as well as lower familiarity, without affecting recollection. Experiment 4 provided a manipulation check on this procedure through a delay manipulation that preferentially affected recognition followed by cued-recall success.     

On the differential nature of implicit and explicit memory

In this article, we report two experiments that provide further evidence concerning the differential nature of implicit and explicit memory. In Experiment 1, subjects first undertook a sentenceverification task. While carrying out this task, half of the subjects were also required to carry out a secondary processing task involving tone monitoring. Twenty-four hours later, the subjects’ memory for target items in the sentence-verification task was tested explicitly by means of a recognition task and implicitly by examining the extent to which the items primed fragment completion. Recognition performance was significantly impaired by the imposition of secondary processing demands during the original learning phase. In contrast, fragment completion was completely unaffected by this additional processing, even though substantial priming was observed. In Experiment 2, we examined whether priming in fragment completion is influenced by the nature of repetition during initial learning. Subjects studied a list of target items that were each repeated twice. Halfthe items were repeatedimmediately (lag 0) and halfwere repeated after six intervening items (lag 6). Memory for the itemswas assessed by recognition and by priming in fragment completion. Recognition was affected by lag, with lag 6 items being recognized better than lag 0 items. However, although significant priming was obtained, the extent of this priming was uninfluenced by lag. These data indicate two additional dimensions along which implicit and explicit memory differ and, furthermore, they support recent conceptualizations of processing differences underlying these two forms of memory.     

The picture superiority effect in a cross-modality recognition task

Words and pictures were studied, and recognition tests were given in which each studied object was to be recognized in both word and picture format. The main dependent variable was the latency of the recognition decision. The purpose was to investigate the effects of study modality (word or picture), of congruence between study and test modalities, and of priming resulting from repeated testing. Experiments 1 and 2 used the same basic design, but the latter also varied retention interval. Experiment 3 added a manipulation of instructions to name studied objects, and Experiment 4 deviated from the others by presenting both picture and word referring to the same object together for study. The results showed that congruence between study and test modalities consistently facilitated recognition. Furthermore, items studied as pictures were more rapidly recognized than were items studied as words. With repeated testing, the second instance was affected by its predecessor, but the facilitating effect of picture-to-word priming exceeded that of word-to-picture priming. The findings suggest a two-stage recognition process, in which the first is based on perceptual familiarity and the second uses semantic links for a retrieval search. Common-code theories that grant privileged access to the semantic code for pictures or, alternatively, dual-code theories that assume mnemonic superiority for the image code are supported by the findings. Explanations of the picture superiority effect as resulting from dual encoding of pictures are not supported by the data.     

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.     

The decay of short-term implicit memory: Unpacking lag

McKone (1995) reported a short-lived repetition priming effect, superimposed on long-lived priming. This short-term implicit memory survived a few intervening items and several seconds for words but decayed precipitously for nonwords, producing a lag 3 lexicality interaction. Here, mechanisms of decay are studied by disconfounding the time delay and interference components of lag. In Experiment 1, time delay was varied while number of intervening items was held constant, and vice versa. In Experiment 2, priming was plotted as a function of time delay, with and without intervening items. Using a lexical decision task, both experiments found independent contributions of time and interference to the decay of short-term priming. Further, Experiment 2 attributed the lag 3 lexicality interaction to a particular sensitivity of nonword traces to interference. An illustration of how these effects might arise in the word recognition system is provided.     

Persistence and relapse of reinforced behavioral variability

The present study examined persistence and relapse of reinforced behavioral variability in pigeons. Pigeons emitted four‐response sequences across two keys. Sequences produced food according to a lag schedule, in which a response sequence was followed by food if it differed from a certain number of previous sequences. In Experiment 1, food was delivered for sequences that satisfied a lag schedule in both components of a multiple schedule. When reinforcement was removed for one component (i.e., extinction), levels of behavioral variability decreased for only that component. In Experiment 2, food was delivered for sequences satisfying a lag schedule in one component of a multiple schedule. In the other component, food was delivered at the same rate, but without the lag variability requirement (i.e., yoked). Following extinction, levels of behavioral variability returned to baseline for both components after response‐independent food delivery (i.e., reinstatement). In Experiment 3, one group of pigeons responded on a lag variability schedule, and the other group responded on a lag repetition schedule. For both groups, levels of behavioral variability increased when alternative reinforcement was suspended (i.e., resurgence). In each experiment, we observed some evidence for extinction‐induced response variability and for variability as an operant dimension of behavior.     

Reflections of the mirror effect for item and associative recognition

In five experiments, participants studied pairs of words and yes/no recognition memory for both item and associative information was tested. Two stimulus manipulations, nouns versus nonnouns and high versus low word concreteness, produced the mirror effect for both item and associative recognition. The mirror effect was reflected in both measures of accuracy and response latency. A word frequency manipulation, however, produced the mirror effect only for item recognition. Two additional experiments showed that the mirror effect could also be obtained between nouns and nonnouns and between high and low concrete words for associative recognition in a forced-choice recognition procedure. The results extend the generality of the mirror effect to measures of response latency and to associative recognition and also suggest that similar retrieval and decision processes underlie recognition of item and associative information.     

Judgments of recency and their relation to recognition memory

Subjects went through a list of 550 high- and low-frequency words (Experiment 1) or concrete and abstract words (Experiment 2) in which individual items were repeated at lags of 5 to 30 other items. They made old versus new recognition decisions on each word and followed each "old" response with a numerical judgment of recency (JOR). Recognition judgments displayed the mirror effect. Conditionalized on recognition, JORs were shorter for low-frequency words than for high-frequency words, and shorter for concrete words than for abstract words. This was true at every lag, suggesting that recognition and JOR may have a common basis. However, recognition confidence ratings obtained in Experiment 3 proved much less sensitive than JOR to test lag. Memory models applicable to multiple judgment tasks will be needed to account for such findings.     

Retrieval of item frequency information in a continuous memory task

The accuracy and response latency of absolute frequency judgments were measured as a function of test lag (the number of intervening items between presentations of a test item) in a continuous memory task. Frequency was varied from one to three presentations in Experiments 1 and 2 and from one to five presentations in Experiment 3. The proportion of correct responses decreased as frequency increased, and correct mean response time tended to increase with frequency. Both accuracy and correct mean response time were found to be largely a function of the most recent test lag. The lag-latency functions were best described by piecewise linear functions, with the breakpoint occurring between lags 1 and 2. Continuous frequency estimation was also shown to improve with extended practice. The implications of the results are discussed with reference to trace strength, numerical-inference, and multiple-trace theories of frequency discrimination.     

Word frequency, repetition, and lexicality effects in word recognition tasks: beyond measures of central tendency

Response time (RT) distributions obtained from 3 word recognition experiments were analyzed by fitting an ex-Gaussian function to the empirical data to determine the main effects and interactive influences of word frequency, repetition, and lexicality on the nature of the underlying distributions. The ex-Gaussian analysis allows one to determine if a manipulation simply shifts the response time (RT) distribution, produces a skewing of the RT distribution, or both. In contrast to naming performance, the lexical decision results indicated that the main effects and interactions of word frequency, repetition, and lexicality primarily reflect increased skewing of the RT distributions, as opposed to simple shifts of the RT distributions. The implications of the results were interpreted within a hybrid 2-stage model of lexical decision performance.