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 storage and retrieval processes in person memory

In this article, a general associative storage and retrieval theory of person memory is proposed, and seven experiments that test various aspects of the theory are reported. Experiment 1 investigated memory for behavioral information that is congruent with, incongruent with, or irrelevant to a prior impression. The results indicated that incongruent events are best recalled and irrelevant events are most poorly recalled. Experiment 2 replicated this effect and demonstrated that there are systematic individual differences that are consistent with the general nomothetic model proposed. The results of Experiment 3 indicated that, relative to a baseline condition, adding incongruent items to the list increases the probability of recalling congruent items but has no effect on the recall of irrelevant items. Both effects are predicted by the model. Experiment 4 provided support for the retrieval assumptions of the theory by demonstrating that there is a systematic order in which various types of items are recalled, as well as consistent differences in interresponse times. Experiments 5 and 6 demonstrated that the model is relevant to situations in which data driven, as well as conceptually driven, processes are involved. Finally, Experiment 7 examined a special case in which the theory predicts greater recall of congruent than incongruent behavioral events. The results of all seven experiments provide converging evidence for a general theory of person memory, and they have implications for a number of issues related to the study of person memory and social judgment.     

Associative encoding and retrieval in Alzheimer's and Huntington's disease

The associative encoding and retrieval abilities of patients with dementia of the Alzheimer type (DAT) and patients with Huntington's disease (HD) were investigated using an encoding specificity paradigm. When compared to age- and education-matched intact control subjects, both patient groups were severely (and equally) impaired on overall memory for word lists. However, the HD and DAT patients showed differential improvement in recall performance with the introduction of associated cues during stimulus presentation and recall. Although the HD patients, like intact subjects, were able to benefit from semantic retrieval cues (strong and weak) which were present during input, the performance of the patients with DAT improved only with the introduction of strong cues at output, regardless of whether the cues were present or absent during initial presentation. These findings suggest that patients with DAT failed to encode the semantic relationship between the to-be-recalled and cue words and simply generated free associations to the cue words during retrieval. Similarities between the performances of the patients with DAT and alcoholic Korsakoff patients are noted and discussed with regard to the neuropathological basis of the disorders.     

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 strength level and retrieval inhibition in semantic memory

In a series of investigations, E. F. Loftus (1973; G. R. Loftus & E. F. Loftus, 1974; E. F. Loftus, Senders, & Turkletaub, 1974) discovered that the latency of item retrieval from a semantic category was reduced if it immediately followed an earlier retrieval from the same category, a phenomenon attributed to spreading activation. Subsequently, Brown (1981) discovered an increase in latency across extended retrievals from a single semantic category. The present investigation followed up this finding by comparing exemplars that varied in strength of association to the category name. The probability of obtaining inhibition (longer latencies and increased errors) was inversely related to the associative strength of the exemplars. The results suggest that low-strength category associates build up inhibition more rapidly because they accrue situational strength relatively more rapidly than high-strength associates.     

An asymmetry between memory encoding and retrieval. Revelation, generation, and transfer-appropriate processing

Transfer-appropriate-processing accounts of memory emphasize the similarity of encoding and retrieval processes, and imply that experimental manipulations should have similar effects on encoding and retrieval. Exceptions to this expectation are thus of great interest, but extant exceptions (produced by studies using divided attention, alcohol, and benzodiazepines) are debatable, single dissociations between encoding and retrieval. The present experiments demonstrate a reversed dissociation, in which the same variable produced opposite effects when implemented at encoding and retrieval. At encoding, participants either solved anagrams of study words or read intact study words. At retrieval, participants likewise solved anagrams or read intact words prior to making recognition memory judgments. Compared with reading intact words, solving anagrams at encoding enhanced later recognition accuracy, whereas solving anagrams at test impaired accuracy. These results were obtained with old/new decisions (Experiment 1) and with confidence ratings (Experiment 2).     

Associative retrieval processes in the human medial temporal lobe: hippocampal retrieval success and CA1 mismatch detection

Hippocampal subfields CA(3) and CA(1) are hypothesized to differentially support the generation of associative predictions and the detection of associative mismatches, respectively. Using high-resolution functional MRI, we examined hippocampal subfield activation during associative retrieval and during subsequent comparisons of memory to matching or mismatching decision probes. Activity in the dentate gyrus/CA(2/3), CA(1), and other medial temporal lobe subregions tracked associative retrieval success, whereas activity in CA(1) and the perirhinal cortex tracked the presence of associative mismatches. These data support the hypothesis that CA(1) acts as a "comparator," detecting when memory for the past and sensory input in the present diverge.     

The effects of search criteria and retrieval cue availability on memory for words

The effects of search criteria upon recall performance following a word classification task were investigated. Rival hypotheses were tested, one based on the number of cues available at retrieval and the other on the amount of processing carried out during classification. After being presented with two-component category names, subjects classified words on the basis of either category membership or the number of semantic components the words shared with a target category, and then they received an unexpected recall test. Experiment 1 favored an amount-of-processing explanation, but it was felt that redundancy in the stimulus materials might invalidate this conclusion. Experiment 2 confirmed this suspicion and clearly supported an explanation in terms of retrieval cue availability. The notion of partial semantic processing of words is discussed, and it is argued that the number of congruent encodings formed during classification can be used as an index of elaboration and subsequent memory performance.     

Concurrent task effects on memory encoding and retrieval: Further support for an asymmetry

Several studies have demonstrated that divided attention at encoding significantly reduces memory performance, whereas divided attention at retrieval affects memory performance only minimally. However, the possibility exists that retrieval processes have shown such resilience because the concurrent tasks used have often not been very demanding. To assess this possibility, we used independent manipulations of the concurrent task during either encoding or retrieval that included stimulus-response compatibility and participant- versus experimenter-controlled pace. In addition, we manipulated the distribution of practice that the participants received with the primary and the concurrent tasks. The results replicated and extended those recently reported by Rohrer and Pashler (2003), indicating that although memory performance is negatively affected by divided attention at retrieval, especially with noncompatible stimulus-response mapping in the concurrent task, this effect was much smaller than that at encoding, in line with the asymmetry notion. Furthermore, experimenter versus participant control of the concurrent task had no effect on memory retrieval. Finally, under conditions of equal practice with both the memory and the concurrent tasks, memory retrieval was affected only to a small degree. In contrast to encoding processes, the processes involved in retrieval accuracy appear, in many cases, to be less interrupted by divided attention, although this protection requires substantial resources.     

Inference,explanation, and asymmetry

Explanation is asymmetric: if A explains B, then B does not explain A. Traditionally, the asymmetry of explanation was thought to favor causal accounts of explanation over their rivals, such as those that take explanations to be inferences. In this paper, we develop a new inferential approach to explanation that outperforms causal approaches in accounting for the asymmetry of explanation.

     

Functional asymmetry of human prefrontal cortex: encoding and retrieval of verbally and nonverbally coded information

There are several views about the organization of memory functions in the human prefrontal cortex. One view assumes a process-specific brain lateralization according to different memory subprocesses, that is, encoding and retrieval. An alternative view emphasizes content-specific lateralization of brain systems involved in memory processes. This study addresses this apparent inconsistency between process- and content-specific lateralization of brain activity by investigating the effects of verbal and nonverbal encoding on prefrontal activations during encoding and retrieval of environmental novel sounds using fMRI. An intentional memory task was applied in which subjects were required either to judge the sounds' loudness (nonverbal encoding task) or to indicate whether or not a sound can be verbally described (verbal encoding task). Retrieval processes were examined in a subsequent yes/no recognition test. In the study phase the right posterior dorsolateral prefrontal cortex (PFC) was activated in both tasks. During verbal encoding additional activation of the left dorsolateral PFC was obtained. Retrieval-related fMRI activity varied as a function of encoding task: For the nonverbal task we detected an activation focus in the right posterior dorsolateral PFC whereas an activation in the left dorsolateral PFC was observed for the verbal task. These findings indicate that the right dorsolateral PFC is engaged in encoding of auditory information irrespective of encoding task. The lateralization of PFC activity during retrieval was shown to depend on the availability of verbal codes, with left hemispheric involvement for verbally and right hemispheric activation for nonverbally coded information.     

Search asymmetry, sustained attention, and response inhibition

In the present experiment, we used search asymmetry to test whether the sustained attention to response task is a better measure of response inhibition or sustained attention. Participants performed feature present and feature absent target detection tasks using either a sustained attention to response task (SART; high Go low No-Go) or a traditionally formatted task (TFT; high No-Go low Go) response format. In addition to performance, we employed functional near infrared spectroscopy (fNIRS) to measure lateral cerebral oxygenation levels and self-reports of Tense Arousal, Energetic Arousal, task related and unrelated thoughts occurring during the tasks. Detections were lower and reaction times longer in the feature absent search than the feature present search regardless of response format. Detections were lower, but reaction times shorter in the SART than the TFT regardless of feature search. Greater right than left frontal hemisphere activation occurred in the SART than the TFT. In addition, the SART was more fatiguing based on self-reports than the TFT, but there were no differences in Task-Unrelated Thoughts across task conditions. Overall, the results suggest the SART places high response inhibition, not necessarily sustained attention, demands on participants.     

Smilansky, Arneson, and the asymmetry of desert

Desert plays an important role in most contemporary theories of retributive justice, but an unimportant role in most contemporary theories of distributive justice. Saul Smilansky has recently put forward a defense of this asymmetry. In this study, I argue that it fails. Then, drawing on an argument of Richard Arneson’s, I suggest an alternative consequentialist rationale for the asymmetry. But while this shows that desert cannot be expected to play the same role in distributive justice that it can play in retributive justice, it does not fully vindicate the asymmetry, since desert can still play an important role in the former.     

Associative symmetry and memory theory

This article reexamines the theory and data concerning two opposing views of episodic association. The independent association hypothesis (IAH) sees associations as unidirectional and separately modifiable links between individual item representations. The associative symmetry hypothesis (ASH) sees an association as a holistic conjunction of the constituent items, blending the elements of their representations into a new one. In early tests of these hypotheses, experimenters compared forward and backward recall of paired associates, looking for asymmetries. Although some studies showed significant differences between forward and backward recall, the vast majority did not. The author of this study used a mathematical analysis of distributed memory models to reexamine this classic question. These analyses revealed that symmetric and asymmetric models can mimic each other, offering identical predictions regarding forward and backward recall. To distinguish these models, the author examined the correlation between forward and backward recall at the level of individual pairs of items. Both this correlation and the correlation between recall of pairs tested in the same direction were near unity. These results provide new evidence favoring the ASH over the IAH.     

Associative frequency and response latency

FlekkØy, K. Associative frequency and response latency. Scand. J. Psychol., 1973, 14, 199–202.MdashWith 176 Norwegian subjects in a single-word free-association experiment, latency of response was found to relate more highly to the number of different words associated with a stimulus word (D), than to the response frequency of the words involved. D is therefore assumed to reflect a basic characteristic of the associative relationship between the stimulus and response words. The inverse relationship between associative frequency and latency is interpreted to mean that frequency reflects some relatively frequent order of preference of possible response words for individual subjects.     

正结合演算

从结构推理的观点来看,结合演算是一种很弱的逻辑,因为它仅容纳一种结构规则,即“结合规则”。正结合演算作为一种“正命题逻辑”,是结合演算的基础。本文构建了正结合演算结构推理系统BL和对应的公理系统B,阐述了结合演算拒斥“交换规则”、“收缩规则”和“弱化规则”的理论意义和应用价值,证明了系统BL和系统B的等价性。