Age of acquisition's effect on memory for semantically associated word pairs

This experiment investigated the effects of age of acquisition (AoA) in memory for associated word pairs in a cued recall task. Participants studied a list of frequency-controlled early- and late-acquired words in semantically related pairs and then were asked to recall the second word of the pair when cued with the first. Reaction time effects were found, showing that a late-acquired cue for an early-acquired target word was responded to significantly faster than other combinations. Additionally, late-acquired target words resulted in significantly more accurate responses. As significant differences were found even when frequency was controlled, the effects must therefore stem from the manipulations of AoA. Given this evidence, the implications for AoA's effects on the organization of semantic memory are explored.     

The negative generation effect: Delineation of a phenomenon

In four experiments employing between-list designs, generation was found to have negative effects on free recall of word pairs and on cued recall of the second word. In addition, generation had negative effects on measures of word-pair integration and on clustering in recall. In contrast, positive effects of generation were found on free recall of second words alone, and on a recognition test for memory of the second word. It was concluded that in between-list designs, generation led to greater individual-item processing of the generated term than reading, but this processing occurred at the expense of processing the relation between the words in a pair and processing the relations between different pairs in a list.     

Is scanning in probed order recall articulatory?

We consider how theories of serial recall might apply to other short-term memory tasks involving recall of order. In particular, we consider the possibility that when participants are cued to recall an item at an arbitrary position in a sequence, they covertly serially recall the list up to the cued position. One question is whether such “scanning” is articulatory in nature. Two experiments are presented in which the syllabic length of words preceding and following target positions were manipulated, to test the prediction of an articulatory-based mechanism that time to recall an item at a particular position will depend on the number of preceding long words. Although latency was dependent on target position, no word length effects on latency were observed. Additionally, the effects of word length on accuracy replicate recent demonstrations in serial recall that recall accuracy is dependent on the word length of all list items, not just that of target items, in line with distinctiveness assumptions. It is concluded that if scanning does occur, it is not carried out by covert or overt articulation.     

Integrative and semantic relations equally alleviate age-related associative memory deficits

Two experiments compared effects of integrative and semantic relations between pairs of words on lexical and memory processes in old age. Integrative relations occur when two dissimilar and unassociated words are linked together to form a coherent phrase (e.g., horse-doctor). In Experiment 1, older adults completed a lexical-decision task where prime and target words were related either integratively or semantically. The two types of relation both facilitated responses compared to a baseline condition, demonstrating that priming can occur in older adults with minimal preexisting associations between primes and targets. In Experiment 2, young and older adults completed a cued recall task with integrative, semantic, and unrelated word pairs. Both integrative and semantic pairs showed significantly smaller age differences in associative memory compared to unrelated pairs. Integrative relations facilitated older adults' memory to a similar extent as semantic relations despite having few preexisting associations in memory. Integratability of stimuli is therefore a new factor that reduces associative deficits in older adults, most likely by supporting encoding and retrieval mechanisms.     

Primacy and recency in primed free association and associative cued recall

Two experiments compared the serial positions of primed words in an implicit free association test with words recalled in a cued recall test. In both tests, weakly or strongly related word pairs were studied, and the first words of each pair formed the test cues. In the implicit test, weakly related words pairs showed primacy and extended recency effects but strongly related word pairs did not. In the explicit test, both weakly and strongly related word pairs showed primacy and extended recency effects. These functional dissociations between implicit and explicit memory tests indicate that strongly related word pairs are encoded together because they have unitized memory representations that function as integrated units without requiring any additional associative links to be made, but that an additional system or process is required to strengthen weakly related word pairs during encoding. In addition, a further additional system or process is accessed by explicit retrieval.     

Do novel associative word stem completion and cued recall share the same memory retrieval processes?

The aim of this study was to determine whether word stem completion for novel associations between cue and target words was mediated by automatic unconscious memory processes or effortful memory processes under conscious control. This was done by applying full and divided attention conditions at test to stem completion, cued recall, and recognition, and by administering a questionnaire that probed the memory strategies used by subjects during the completion test. Divided attention had no effect on stem completion performance, but did reduce associative cued recall. Recognition performance was weakened overall by divided attention, but the associative effect was similar under both attention conditions. This suggested that novel associative word stem completion was mediated by automatic retrieval processes. However, the results of the questionnaire indicated that only subjects who attempted to remember the words from the study phase during the completion task showed any novel associative effect. It is concluded that novel association word stem completion and cued recall share automatic retrieval processes, which nevertheless give rise to the experience of remembering.     

Selective access in cued recall: The roles of retrieval cues and domains of encoding

The purpose of these experiments was to determine whether retrieval access in cued recall can be selectively restricted to a single domain of encoding when information has been encoded within two domains as different as word sound and word meaning. In Experiment 1, the subjects studied pairs of rhyming words differing in rhyme set size under verbal-repetition or interactive-imagery instructions. Recall was cued with study-context rhymes, with extralist rhymes, or with extralist associates. The results indicated that rhyme set size and instructional effects were found no matter how recall was cued, indicating that both domains of encoding were always accessed. In Experiment 2, potential effects of study time and overt naming of the test cues were explored. These results indicated that both domains of encoding were accessed, except when long study times were available and subjects did not have to name the rhyme test cues. Rhyme set-size effects were eliminated under these conditions, suggesting that selective access to encoded meaning is possible in cued recall. Retrieval access in this task appears to be more controlled by domains of encoding than by information directly available in the cue, and access to encoded information can be restricted to a single domain.     

Effects of level of retrieval success on recall-related frontal and medial temporal lobe activations

Brain dedicated single photon emission computed tomography (SPECT) was used to compare the neuroactivation produced by the cued recall of response words in a set of studied word pairs with that produced by the cued retrieval of words semantically related to unstudied stimulus words. Six of the 12 subjects scanned were extensively trained so as to have good memory of the studied pairs and the remaining six were minimally trained so as to have poor memory. When comparing episodic with semantic retrieval, the well-trained subjects showed significant left medial temporal lobe activation, which was also significantly greater than that shown by the poorly trained subjects, who failed to show significant medial temporal lobe activation. In contrast, the poorly trained subjects showed significant bilateral frontal lobe activation, which was significantly greater than that shown by the well-trained subjects who failed to show significant frontal lobe activation. The frontal activations occurred mainly in the dorsolateral region, but extended into the ventrolateral and, to a lesser extent, the frontal polar regions. It is argued that whereas the medial temporal lobe activation increased as the proportion of response words successfully recalled increased, the bilateral frontal lobe activation increased in proportion to retrieval effort, which was greater when learning had been less good.     

Semantic specificity in cued recall

In three cued recall experiments, extralist retrieval cues that were congruous in meaning to an encoded target pair of words produced better recall of the targets than wh6n the cuetarget relation was incongruous. However, this result, which differs from that of other experiments, depended in some cases on scoring recall of a target pair when either member of the pair was recalled. It is argued that (1) pairs of words are typically stored as higher order units, (2) the best test procedure is to request recall of both members of the pair when an extralist cue is presented, and (3) semantic features provide an important dimension in the mnemonic representation of word events.     

Effects of emotion and age on performance during a think/no-think memory task

Recent studies have demonstrated that young adults can voluntarily suppress information from memory when directed to. After learning novel word pairings to criterion, participants are shown individual words and instructed either to "think" about the associated word, or to put it out of mind entirely ("no-think"). When given a surprise cued recall test, participants typically show impaired recall for no-think words relative to think or "control" (un-manipulated) words. The present study investigated whether this controlled suppression effect persists in an aged population, and examined how the emotionality of the to-be-suppressed word affects suppression ability. Data from four experiments using the think/no-think task demonstrate that older and younger adults can suppress information when directed to (Experiment 1), and the age groups do not differ significantly in this ability. Experiments 2 through 4 demonstrate that both age groups can suppress words that are emotional (positive or negative valence) or neutral. The suppression effect also persists even if participants are tested using independent probe words that are semantically related to the target words but were not the studied cue words (Experiments 3 and 4). These data suggest that the cognitive functioning necessary to suppress information from memory is present in older adulthood, and that both emotional and neutral information can be successfully suppressed from memory.     

Incidental formation of episodic associations: The importance of sentential context

The influence of relevant semantic context on the incidental formation of episodic associations between words was probed in two experiments. In Experiment 1, we examined the influence of associations formed incidentally between unrelated words presented either in isolation or embedded in a sentential context on subsequent explicit paired-associate leaning tested by cued recall. The results of Experiment 1 showed that the cued-recall rate of words studied in sentential context was higher than that of words co-occurring in isolated pairs. A subsequent single-items recognition test showed equal item memory for words studied in sentences than for words studied in isolated pairs, suggesting that the sentential context effect in cued recall indeed reflected stronger associations between paired words rather than better memory for single words. In Experiment 2, we ruled out memory for the entire sentence as an alternative explanation for the results of Experiment 1. We suggest two possible mechanisms to account for this advantage: First, pairs embedded in a sentence undergo semantic elaboration that might lead to the incidental formation of an association between them. Second, words embedded in a sentence enjoy the conjoint activation of compatible semantic features, a fact that may also facilitate the formation of an episodic association between them. The implications of these results for computational models using word representations based on co-occurrence data are discussed.     

Implicit and explicit memory bias for threat in post-traumatic stress disorder.

We investigated explicit (cued recall) and implicit (word completion) memory in Vietnam combat veterans with (n = 24) and without (n = 24) post-traumatic stress disorder (PTSD). Half of the subjects in each group encoded combat, social threat, positive, and neutral words elaboratively, whereas the others encoded these words nonelaboratively. On the cued recall test, under both encoding conditions, both groups recalled more combat words than other words. However, difference scores obtained by subtracting the mean recall for neutral words from the mean recall scores for the other words revealed that PTSD patients exhibited a relative explicit memory bias for combat words. That is, PTSD patients tended to exhibit poor memory for everything but combat words. On the word completion test, only PTSD subjects exhibited an implicit memory bias for combat words. This bias was greater for primed than for unprimed words, thereby ruling out a response bias. Such memory bias may underlie the 'reexperiencing' symptoms characteristic of PTSD (e.g. intrusive thoughts, nightmares).     

Altering memory through recall: The effects of cue-guided retrieval processing

Three experiments were designed to investigate the influence of initial recall on memory by assessing delayed recall after different immediate cued-recall tests. In all experiments, subjects performed semantic and phonemic encoding tasks on a word list. The subjects then received a cued-recall test that cued the target using the same word as the context word in the encoding task, a test that cued the target with a word from the same level at which the target was encoded, a test that cued the target with a cue from a different level at which the target was encoded, or no immediate-recall test. One day later, the subjects performed a final cued-recall test in which the type of cue (semantic or phonemic) was varied. Consistently, delayed recall was facilitated primarily when the cue on the immediate test was from the same level as the cue on the delayed test. This pattern of facilitation suggests that immediate cued-recall produces an elaboration of an existing memory representation that is closely tied to the type of cue used on the immediate test.     

Prior knowledge: the effects of natural category size on memory for implicitly encoded concepts

Studying a familiar word activates its associates, and these associates affect the likelihood of recalling the studied word in a cued recall task. These experiments examined variables that normally affect memory for the studied word to determine if they have similar effects on memory for the word's associates. Memory for associates was tested by cued recall (Experiments 1-3) or by recognition (Experiments 4-5), with the number and strength of the associates varied in all experiments. In different experiments, test instructions (direct-indirect), distractor tasks, lag, and amount of practice were manipulated. Provided that subjects were not distracted prior to test, the probability of recalling associates of the studied word decreased with the number of associates activated and with their strength under all conditions. The strength of the associates but not their number affected recognition. In general, variables that affected recall and recognition of studied words had parallel effects on their associates.     

情绪效价的记忆增强效应:存储或提取优势?

情绪效价和情绪唤醒是描述情绪的两个维度。情绪增强记忆效应表明情绪唤醒事件的记忆往往优于非情绪唤醒事件的记忆,但关于积极情绪记忆和消极情绪记忆哪个在记忆中处于优势仍存在争论。实验以情绪词对和中性词对为实验材料。实验一探讨积极情绪词语或消极情绪词语的记忆优势; 实验二探讨积极情绪环境或消极情绪环境中中性词语的记忆优势。在两种实验条件下,积极情绪下的自由回忆都优于消极情绪下的自由回忆; 多项加工树的存储—提取模型使用实验自由回忆和线索回忆的结果将记忆的存储和提取优势分离开来,结果表明:积极情绪事件记忆优势发生在存储阶段,而积极情绪环境记忆优势发生在存储和提取阶段; 积极情绪事件记忆偏向支持“刺激后编码增强假设”,积极情绪环境记忆偏向支持“唤醒—偏向竞争假设”。     

The use of hand gestures as self-generated cues for recall of verbally associated targets

This study examined the effects of hand gestures as cues for recall of 40 previously described abstract and concrete words. Participants were either self-cued (SC) with their own self-generated gestures, other-cued (OC) with someone else's gestures, or shown no cues (NC). The SC group had significantly better recall for both word types than either the OC or NC immediately and at a 2-week retrieval interval. Results also showed that when the SC group produced a meaningful gesture, concrete words were cued significantly more often than abstract words, but when total recall (cued and residual) was considered, abstract words were recalled equally well. These results are discussed in the context that hand gestures are a component of subjective organization and are thus distinctive cues for the producer that may facilitate or prime recall.     

Age-of-acquisition effects in lexical and episodic memory tasks

This paper reports four experiments on the effects of word age of acquisition in verbal tasks. In all cases, multiple-regression analysis was used to assess the relative effects of age as opposed to other potentially relevant word attributes. Experiments 1 and 2 concerned lexical memory tasks. In Experiment 1, picture naming speeds were found to be mainly determined by picture codability and name age of acquisition. In Experiment 2, it was found that when subjects produced words in response to bigram cues, early acquired target words were more likely to be produced than later acquired words, even when frequency and other word attributes were taken into account. The remaining two experiments dealt with the episodic memory tasks of free recall and recognition. No age effects were found in these tasks. It was concluded that early age of acquisition facilitates retrieval from lexical memory but has no significant effect in episodic memory tasks.     

Recency effects in direct and indirect memory tasks

In three experiments, subjects learned two lists under incidental conditions and were then given either a part-word or a word (extralist associate) cue. Each cue was related to one word in each list. Half the subjects were given production instructions (an indirect memory test), and half were given cued recall instructions (a direct memory test). When the interval between List 2 and the test was shortened, recency effects were found for part-word cues for both cued recall and production instructions. Little or no recency effects were found with word cues. These results are incompatible with a simple distinction between the types of memory trace or information that are tapped by direct as opposed to indirect memory tasks. Possible causes for the recency effect and for the difference between word and part-word cues are discussed.     

Cognitive load hypothesis of item-method directed forgetting

This study examined the effect of the processing demands of to-be-remembered (TBR) words on item-method directed forgetting. Experiment 1 found that a standard memory group remembered fewer to-be-forgotten (TBF) words than a naming group, in which participants simply named the TBR words during the study phase, even though both groups were equally instructed to forget the TBF words. Experiment 2 manipulated the number of TBR words in the study list, keeping the number of TBF words constant, and found that TBF word forgetting was more difficult in the few TBR words condition than the more TBR words condition. The same pattern was found in the result of Experiment 3 when a cued recall test, instead of a free recall test, was used. In all the experiments, participants were asked to recall the TBF words before the TBR words. These findings are consistent with the cognitive load hypothesis that it is easier to forget when there are fewer cognitive resources available during encoding.     

Cognitive load hypothesis of item-method directed forgetting

This study examined the effect of the processing demands of to-be-remembered (TBR) words on item-method directed forgetting. Experiment 1 found that a standard memory group remembered fewer to-be-forgotten (TBF) words than a naming group, in which participants simply named the TBR words during the study phase, even though both groups were equally instructed to forget the TBF words. Experiment 2 manipulated the number of TBR words in the study list, keeping the number of TBF words constant, and found that TBF word forgetting was more difficult in the few TBR words condition than the more TBR words condition. The same pattern was found in the result of Experiment 3 when a cued recall test, instead of a free recall test, was used. In all the experiments, participants were asked to recall the TBF words before the TBR words. These findings are consistent with the cognitive load hypothesis that it is easier to forget when there are fewer cognitive resources available during encoding.