Interference and the representation of order within associations

In the presence of interference, recall of pairs can critically depend on the diagnostic power of memory of the order of items within the pair. Models of pair memory make different assumptions about whether and how such order information is stored, from convolution-based models, which assume no explicit storage of order, to matrix models and several models that assume a pair is learned by concatenating the representations of the constituent items, which lead to perfect within-pair order memory (given retrieval of the pair). Here we investigate memory for associations and within-pair order by examining the relationship between forward and backward probes of pairs subject to order-dependent associative interference in a double-function list paradigm. Associative interference disrupted the high correlation between forward and backward recall accuracy that is typically observed in standard paired-associate learning, challenging matrix and concatenation-based models. However, participants could overcome some interference due to within-pair order ambiguity, challenging directionally ambiguous convolution-based models. Unexpectedly, the test–retest correlation was reduced for pairs under the influence of interference compared to control pairs. This finding is incompatible with all existing implementations of the model classes we consider. Any model must include an assumption that order encoding (but not retrieval) is unreliable, and the form of this additional mechanism may depend intimately on how a given model is designed. In sum, our findings suggest that within-pair order memory is neither poor nor perfect, pointing to a fallible mechanism for within-pair order learning in verbal association-memory tasks.     

Interference and the representation of order within associations

In the presence of interference, recall of pairs can critically depend on the diagnostic power of memory of the order of items within the pair. Models of pair memory make different assumptions about whether and how such order information is stored, from convolution-based models, which assume no explicit storage of order, to matrix models and several models that assume a pair is learned by concatenating the representations of the constituent items, which lead to perfect within-pair order memory (given retrieval of the pair). Here we investigate memory for associations and within-pair order by examining the relationship between forward and backward probes of pairs subject to order-dependent associative interference in a double-function list paradigm. Associative interference disrupted the high correlation between forward and backward recall accuracy that is typically observed in standard paired-associate learning, challenging matrix and concatenation-based models. However, participants could overcome some interference due to within-pair order ambiguity, challenging directionally ambiguous convolution-based models. Unexpectedly, the test-retest correlation was reduced for pairs under the influence of interference compared to control pairs. This finding is incompatible with all existing implementations of the model classes we consider. Any model must include an assumption that order encoding (but not retrieval) is unreliable, and the form of this additional mechanism may depend intimately on how a given model is designed. In sum, our findings suggest that within-pair order memory is neither poor nor perfect, pointing to a fallible mechanism for within-pair order learning in verbal association-memory tasks.     

Associative retrieval processes in free recall

I present a new method for analyzing associative processes in free recall. While previous research has emphasized the prominence of semantic organization, the present method illustrates the importance of association by contiguity. This is done by examining conditional response probabilities in the output sequence. For a given item recalled, I examine the probability and latency that it follows an item from a nearby or distant input position. These conditional probabilities and latencies, plotted as a function of the lag between studied items, reveal several regularities about output order in free recall. First, subjects tend to recall items more often and more rapidly from adjacent input positions than from remote input positions. Second, subjects are about twice as likely to recall adjacent pairs in the forward than in the backward direction and are significantly faster in doing so. These effects are observed at all positions in the output sequence. The asymmetry effect is theoretically significant because, in cued recall, nearly symmetric retrieval is found at all serial positions (Kahana, 1995; Murdock, 1962). An attempt is made to fit the search of associative memory model (Raaijmakers & Shiffrin, 1980, 1981) with and without symmetric interitem associations to these data. Other models of free recall are also discussed.     

Associative asymmetry in probed recall of serial lists

For pairs of meaningful items (e.g., words), recall accuracy is nearly identical for forward and backward probes. That is, after studying an A-B pair, subjects can recall A given B as well as they can recall B given A (Kahana, 2002). To assess whether this symmetry property is unique to pairs, we investigated the effects of study direction on probed recall of word triples and serial lists. Two experiments revealed a forward-recall advantage in both triples and serial lists. In addition, compound cues produced better recall than did single-item adjacent cues, which, in turn, produced better recall than did remote cues. These findings suggest a discontinuity between the associative processes supporting memory for pairs and those supporting memory for sequences of three or more items.     

Associative isolation: Unifying associative and list memory

Rather than treating paired associate and serial learning as involving the acquisition of distinct types of information [e.g. Murdock (1974). Human memory: Theory and data. New York: Wiley] I propose an Isolation Principle which treats the two as ends of a continuum. According to this principle, consecutive pairs of items are relatively isolated from other studied items in paired associates learning, but not isolated in serial list learning. The consequence is that variability that dominates forward and backward probed recall is highly correlated in pairs but less so, due to differential interference, in lists. This can explain an important dissociation: whereas forward and backward probes of pairs are nearly perfectly correlated, the correlation is only moderate for serial lists. I demonstrate this in a chaining model by varying item-to-item associative strengths and in a positional coding model by varying the similarity structure of item positions. This enables a range of models to account for data on pairs and lists, as well as potential intermediate or hybrid paradigms, within a single theoretical framework.     

Assessing the effect of lexical variables in backward recall

In a recent study, Bireta et al. (2010) suggested that when participants are required to recall lists of items in the reverse order, more attention is devoted to the recall of order at the expense of item information, leading to the abolition of item-based phenomena (the item and order trade-off hypothesis). In order to test the item and order trade-off hypothesis, we manipulated 4 lexical factors that are well known to influence item retention. The effects of word frequency, of lexicality, of semantic similarity, and of imageability were tested in forward and backward recall. All 4 phenomena were maintained in backward recall, which contradicts the item and order trade-off hypothesis. Instead, we suggest that backward recall might rely on semantic retrieval strategies.     

What is preexisting strength? Predicting free association probabilities,similarity ratings,and cued recall probabilities

Measuring lexical knowledge poses a challenge to the study of the influence of preexisting knowledge on the retrieval of new memories. Many tasks focus on word pairs, but words are embedded in associative networks, so how should preexisting pair strength be measured? It has been measured by free association, similarity ratings, and co-occurrence statistics. Researchers interpret free association response probabilities as unbiased estimates of forward cue-to-target strength. In Study 1, analyses of large free association and extralist cued recall databases indicate that this interpretation is incorrect. Competitor and backward strengths bias free association probabilities, and as with other recall tasks, preexisting strength is described by a ratio rule. In Study 2, associative similarity ratings are predicted by forward and backward, but not by competitor, strength. Preexisting strength is not a unitary construct, because its measurement varies with method. Furthermore, free association probabilities predict extralist cued recall better than do ratings and co-occurrence statistics. The measure that most closely matches the criterion task may provide the best estimate of the identity of preexisting strength.     

Recall of related and unrelated gender-typed item pairs by young children

Aspects of 40 young children's (22 boys, 18 girls; mean age = 51.00 months) recall of related and unrelated item pairs were assessed. Children were primarily white and middle SES. Consistent with previous recall research, boys recalled significantly more pairs, and individual items from pairs, of related gender-typed items than pairs containing unrelated items. Girls recalled significantly more pairs, and individual items from pairs, of related animal items than any other types of related or unrelated pairings. Congruent with the component model of gender role knowledge development, girls showed significantly greater recall of pairs, and individual items from pairs, of same-sex feminine item pairs than other-sex masculine ones. Consistent with previous memory research examining young children's pair recall, boys demonstrated significantly better recall of pairs, and individual items from pairs, containing related same-sex masculine items than pairs with two unrelated items. These data suggest young children conceptualize gender roles as social categories to organize processing of social information.Completion of this project was partially facilitated by an Academic Challenge Award from the University of Toledo. This support is gratefully acknowledged. Special thanks to Narina Nightingale for her comments and suggestions of earlier drafts of this article, to Pamela Hassen, Kim Piper, Laura Underwood, and Shesna Power for data collection efforts, and to the faculty, children, and parents of the Loving Tree Preschool of Toledo, Ohio, and the Basic Beginnings Preschool of Laramie, Wyoming. A shorter version of this paper was presented at the meetings of the Midwestern Psychological Association, Chicago, Illinois, May 1991.     

Forward and backward recall: different response time patterns,same retrieval order

How do people retrieve information in forward and backward recall? To address this issue, we examined response times in directional recall as a function of serial position and list length. Participants memorized lists of four to six words and entered responses at the keyboard. Recall direction was postcued. Response times exhibited asymmetry in terms of direction. In forward recall, response times peaked at the first position, leveling off for subsequent positions. Response times were slower in backward recall than in forward recall and exhibited an inverse U-shaped function with an initial slowdown followed by a continuous speedup. These asymmetries have implications for theoretical models of retrieval in serial recall, including temporal-code, rule-based, and network models. The response time pattern suggests that forward recall proceeds in equal steps across positions, whereas backward recall involves repeated covert cycles of forward recall. Thus, retrieval in both directions involves a forward search.     

Delaying judgments of learning affects memory,not metamemory

Judgments of learning (JOLs) for cue-target word pairs correlate particularly well with later target recall when made under conditions that permit delayed attempts to retrieve the targets--the delayed-JOL effect. Metamemory theories claim that memory monitoring improves under these conditions. However, another theory--the memory hypothesis--claims that the correlation increases because retrieved items receive a boost in recall from spaced study and are assigned high JOLs, whereas unretrieved items receive no spaced study and, therefore, no boost in recall and, consequently, are assigned low JOLs. When we eliminated differences in spaced study by reexposing word pairs following their JOLs, the delayed-JOL effect disappeared, supporting the memory hypothesis.     

Temporal isolation does not facilitate forward serial recall—or does it?

In numerous recent studies in short-term memory, it has been established that forward serial recall is unaffected by the temporal isolation of to-be-remembered items. These findings contradict the temporal distinctiveness view of memory, which expects items that are temporally isolated from their neighbors to be more distinct and hence remembered better. To date, isolation effects have only been found with tests that do not constrain output order, such as free recall. This article reports two experiments that, for the first time, report a temporal isolation effect with forward serial recall, using a running memory task in which the end of the list is unpredictable. The results suggest that people are able to encode and use temporal information in situations in which positional information is of little value. We conclude that the overall pattern of findings concerning temporal isolation supports models of short-term memory that postulate multidimensional representations of items.     

Associative and categorical hypotheses of organization in the free recall of adults and children

Associative and categorical explanations for the organization children and adults display in free recall were tested. It was expected that young children would show output clustering as a function of associations between individual items within categories rather than relationship to the taxonomy itself. Kindergarten, fourth-grade, and tenth-grade subjects were presented with pictures representing the four factorial combinations of high and low interitem association and high and low category relatedness. Each set of pictures could be divided into four taxonomic categories of six items each. Kindergarteners displayed greater category clustering of highly associated items than weak associates. Older subjects showed sensitivity to both organizational dimensions. These data support a hypothesis that young children cluster in recall as a function of associations while older individuals show organizational flexibility which serves to facilitate greater recall.     

Temporal associative processes revealed by intrusions in paired-associate recall

Although much is known about the factors that influence the acquisition and retention of individual paired associates, the existence of temporally defined associations spanning multiple pairs has not been demonstrated. We report two experiments in which subjects studied randomly paired nouns for a subsequent cued recall test. When subjects recalled nontarget items, their intrusions tended to come from nearby pairs. This across-pair contiguity effect was graded, spanning noncontiguously studied word pairs. The existence of such long-range temporally defined associations lends further support to contextual-retrieval models of episodic association.     

Direction of Report in Spatial and Verbal Serial Short term Memory

Four experiments examined the role played by item and order information in determining the effects of order of report of a sequence from short-term memory. Experiments in which list items were re-presented prior to recall so that only their order had to be reported showed no differences in performance between the forward and backward direction of report. This result was found with lists of auditory-verbal, visual-verbal, and spatial stimuli. When the list items were not re-presented, so that recall of both items and order was required, recall in the backward direction of report was significantly worse than in the forward direction of report, both in spatial and verbal tasks. The results point to the symmetry of inter-item associations, though only equivocally so, but they suggest strongly that the processes of spatial and verbal serial recall share many functional characteristics.     

Overt language production plays a key role in the Hebb repetition effect

When asked to recall verbatim a short list of items, performance is very limited. However, if the list of items is repeated across trials, recall performance improves. This phenomenon, known as the Hebb repetition effect (Hebb, 1961; Brain Mechanisms and Learning: A Symposium, pp. 37–51), is considered a laboratory analogue of language learning. In effect, learning a new word implies the maintenance of a series of smaller units, such as phonemes or syllables, in the correct order for a short amount of time before producing them. The sequence of smaller units is typically presented more than once. In the present study, we investigated the role of overt language production in language learning by manipulating recall direction. If the learning of a repeated list of items relies on overt language production processes, changing list production order by manipulating recall direction should impact the learning of the list. In Experiment 1, one list was repeated every third trial, and recall direction of the repeated list changed on the ninth repetition. In Experiment 1a, the repeated list changed from a forward to a backward order recall, where participants had to recall the items in reverse presentation order. In Experiment 1b, the repeated list changed from a backward to a forward order recall. Results showed a cost in recall performance for the repeated list when recall direction switched from forward to backward recall, whereas it was unaffected by the change from backward to forward recall. In Experiment 2, we increased the number of trials before introducing the change from a backward to a forward order recall. Results showed a decrement in recall performance for the repeated list following the change in recall direction, suggesting that language production processes play a role in the Hebb repetition effect.     

小学生预见性偏差及其削弱

采用三种不同去偏差方法,对不同年龄儿童的预见性偏差及削弱进行探讨。实验结果发现,二年级和三年级出现了预见性偏差,五年级没有出现预见性偏差;对于二年级儿童,只有基于理论的去偏差方法才能削弱预见性偏差。而三年级儿童,三种方法都能削弱预见性偏差。结果说明帮助他们建立正确的元认知理论可以有效提高他们元认知监测水平。     

小学生预见性偏差及其削弱

采用三种不同去偏差方法,对不同年龄儿童的预见性偏差及削弱进行探讨。实验结果发现,二年级和三年级出现了预见性偏差,五年级没有出现预见性偏差;对于二年级儿童,只有基于理论的去偏差方法才能削弱预见性偏差。而三年级儿童,三种方法都能削弱预见性偏差。结果说明帮助他们建立正确的元认知理论可以有效提高他们元认知监测水平。     

Ordering and reordering in the auditory and visual modalities

This study investigates the hypothesis that the modality effect (i.e., the often-found recall advantage of the last few items presented in the auditory- rather than visual-input modality) is attributable to a directional auditory trace. Such a directional trace should help performance of forward item-to-item recall, but should hurt performance if mental reordering is required. However, it was found in our Experiment 1 that mental item-to-item reordering of the materials did not affect the modality effect. In Experiment 2, strict control was exercised over the order of recall of chunks of items, as well as over the order of recall within chunks. It was found that the item-to-item reordering of the materials had little effect on the modality effect. However, the larger scale order of recall of the chunks had a large effect on the modality effect. If recall was in a forward order (i.e., first chunk, second chunk, third chunk), there was a dramatic superiority of the auditory materials on the last chunk. If the recall order was backward (third chunk, second chunk, first chunk), the modality effect was inconsequential. These results suggest that the modality effect is related to access to large memorial units rather than to item-to-item associations.     

Multiple roles for time in short-term memory: evidence from serial recall of order and timing

Three experiments are reported that examine the relationship between short-term memory for time and order information, and the more specific claim that order memory is driven by a timing signal. Participants were presented with digits spaced irregularly in time and postcued (Experiments 1 and 2) or precued (Experiment 3) to recall the order or timing of the digits. The primary results of interest were as follows: (a) Instructing participants to group lists had similar effects on serial and timing recall in inducing a pause in recall between suggested groups; (b) the timing of recall was predicted by the timing of the input lists in both serial recall and timing recall; and (c) when the recall task was precued, there was a tendency for temporally isolated items to be more accurately recalled than temporally crowded items. The results place constraints on models of serial recall that assume a timing signal generates positional representations and suggest an additional role for information about individual durations in short-term memory.     

Representational constraints on children's suggestibility

ABSTRACT— In a multistage experiment, twelve 4- and 9-year-old children participated in a triad rating task. Their ratings were mapped with multidimensional scaling, from which euclidean distances were computed to operationalize semantic distance between items in target pairs. These children and age-mates then participated in an experiment that employed these target pairs in a story, which was followed by a misinformation manipulation. Analyses linked individual and developmental differences in suggestibility to children's representations of the target items. Semantic proximity was a strong predictor of differences in suggestibility: The closer a suggested distractor was to the original item's representation, the greater was the distractor's suggestive influence. The triad participants' semantic proximity subsequently served as the basis for correctly predicting memory performance in the larger group. Semantic proximity enabled a priori counterintuitive predictions of reverse age-related trends to be confirmed whenever the distance between representations of items in a target pair was greater for younger than for older children.