The von Restorff effect and measures of organization in normals and retardates

Thirty-two noninstitutionalized retardates and 32 normals of equal mental age (approximately 8 years) heard 10 orders of 10 nouns when the decibel (dB) level of the stimuli was the same and when the dB level of the sixth item was higher. The yon Restorff effect was demonstrated by both groups. The normals’ overall recall was superior to that of the retardates’ recall. Differences in recall were attributed to the normals’ tendency to recall items in the same serial order more consistently. The subjective organization of lists, as measured by order of recall, differed for the normals and retardates; the normal group was more adaptable than the retarded group in adjusting their strategy to different list conditions.     

Recall and recognition measures of paired associate learning in healthy aging

Associate-recognition has received little attention as a potential clinical tool for detecting early Alzheimer's disease (AD). As an important preliminary stage to investigating the paradigm's diagnostic utility, we designed and administered a verbal associate-recognition task to healthy elderly participants (n = 62) and compared their performance to that on traditional cued-recall PAL. In both test conditions, the stimulus list comprised of a mixture of highly imageable and less imageable word pairs. Overall, performance on the associate-recognition task was superior to that on the cued-recall analogue. This 'recognition advantage' was not attributable to the higher baseline or chance guessing rate in the associate-recognition condition, as the size of the recognition advantage varied across learning trials and stimulus imageability. In comparison to performance on the imageable stimuli, performance on the less imageable stimuli was poor in both associate-recognition and cued-recall conditions. Across the delay, performances were more likely to drop in the cued-recall condition than the associate-recognition condition. These results suggest that verbal associate-recognition may be clinically efficacious and better tolerated in elderly populations than traditional cued-recall paradigms. Although these results are encouraging, further research is required to examine the utility of associate-recognition in clinical populations, particularly early AD.     

Age-related differences in the von Restorff isolation effect

When one item is made distinct from the other items in a list, memory for the distinctive item is improved, a finding known as the isolation or von Restorff effect (after von Restorff, 1933). Although demonstrated numerous times with younger adults and children, this effect has not been found with older adults (Cimbalo & Brink, 1982). In contrast to the earlier study, we obtained a significant von Restorff effect for both younger and older adults using a physical manipulation of font colour. The effect size for older adults was smaller than that obtained for younger adults, confirming a prediction of Naveh-Benjamin's (2000) associative deficit hypothesis, which attributes age-related differences in memory performance to older adults' reduced ability to form associations. The findings are consistent with related research in which older adults demonstrate similar—but smaller—benefits for distinctive information to those for younger adults.     

Pause measures during reading and recall in serial list learning

An investigation is reported into pausing and grouping during the serial learning of letter strings, when presented randomly by length and when presented in ascending order. Mean pause times for the reading and recall of longer lists were significantly greater than for lists of shorter span due to extended pausing at specific list positions. In general, reading rhythms were duplicated during recall. Subjects were highly consistent in maintaining their level of pause duration across lists and responded to additions in list length by increasing their number of groups, not by increasing group size. Triadic sequences were the most popular form of spontaneous organization. Pausing measures are discussed as indices of organizational strategies.     

The phonological similarity effect in serial recognition

An experiment is reported examining the effect of consistent phonemic similarity among list items on memory retention in a task that is independent of overt speech production, the serial recognition task. Lists of consonant-vowel-consonant (CVC) words and nonwords were constructed such that although phoneme overlap was manipulated (i.e., shared vowel and final consonant [_VC], initial consonant and vowel [CV_], or the two consonants [C_C]), similarity remained constant. The results show that the influence of sub-syllabic mechanisms on STM performance is independent of speech production processes, and similarity in the pattern of results suggests that the same mechanisms subserve the recall of words and nonwords in STM. It is argued that the results are more consistent with psycholinguistic models than nonlinguistic models of STM, and implications for current STM models are discussed.     

The phonological similarity effect in serial recognition

An experiment is reported examining the effect of consistent phonemic similarity among list items on memory retention in a task that is independent of overt speech production, the serial recognition task. Lists of consonant-vowel-consonant (CVC) words and nonwords were constructed such that although phoneme overlap was manipulated (i.e., shared vowel and final consonant [_VC], initial consonant and vowel [CV_], or the two consonants [C_C]), similarity remained constant. The results show that the influence of sub-syllabic mechanisms on STM performance is independent of speech production processes, and similarity in the pattern of results suggests that the same mechanisms subserve the recall of words and nonwords in STM. It is argued that the results are more consistent with psycholinguistic models than nonlinguistic models of STM, and implications for current STM models are discussed.     

The effect of semantic relatedness on immediate serial recall and serial recognition

Several researchers have reported that learning a particular categorization leads to compatible changes in the similarity structure of the categorized stimuli. The purpose of this study is to examine whether different category structures may lead to greater or less corresponding similarity change. We created six category structures and examined changes in similarity within categories or between categories, as a result of categorization, in between-participant conditions. The best supported hypothesis was that the ease of learning a categorization affects change in within-categories similarity, so that greater (within-categories) similarity change was observed for category structures that were harder to learn.     

The effect of semantic relatedness on immediate serial recall and serial recognition

The present study examined the effects of semantic relatedness on immediate serial recall and serial recognition. Each participant received either blocked or randomly intermixed serial recall or serial recognition trials. Replicating the findings of previous studies (e.g., Saint-Aubin, Ouellette, & Poirier, 2005), semantic relatedness boosted percentage serial recall but also increased order errors, after taking into account the proportion of correctly recalled items, regardless of their orders, in serial recall trials. In serial recognition trials, participants' responses were slower and less accurate for related lists than for unrelated lists. There were intraindividual correlations among order memory measures in serial recall versus serial recognition trials. The implications of these findings for item redintegration theories are discussed.     

The von Restorff effect and induced amnesia: production by manipulation of sound intensity.

When an outstanding item appears in an otherwise homogeneous list of items, the outstanding item is better remembered (the von Restorff effect), and items before and after it may be more poorly remembered (induced amnesia) than corresponding items in a control list. In the present experiments the outstanding item was a word presented as a loud shout among other words presented at normal conversational levels. In two experiments, large retrograde- and anterograde-induced amnesiae effects were demonstrated using a free-recall and a recognition task. In both experiments half of the subjects were told what to expect and were instructed to devise a strategy to eliminate induced amnesia. These instructions failed to eliminate the amnesiac effect. A third experiment was designed to demonstrate an empirical similarity between induced and clinical amnesia. In clinical retrograde (but not anterograde) amnesia, "lost" memories are sometimes recovered with time. Filled delays of 0, 30, or 120 sec interpolated between list presentation and recall demonstrated that induced retrograde amnesia disappeared at the longest delay but induced anterograde amnesia was unchanged. A fourth experiment eliminated some alternate interpretations of the effect.     

Age differences in learning serial patterns: direct versus indirect measures

Adult age differences in learning and retention of a nonverbal sequence were examined using the serial reaction-time task of Nissen and Bullemer (1987), with 20 younger and 20 older Ss. An asterisk appeared in one of 4 spatial locations, and the Ss responded with a corresponding key press. The first 4 blocks each contained 10 repetitions of a 10- or 16-element spatial sequence, and the 5th block contained a random sequence. The difference between response time on Blocks 5 and 4 served as an indirect measure of pattern learning. The direct measure was accuracy in a final generation block in which the Ss predicted which location would appear next. Results were similar to those with verbal materials; the indirect measure revealed age similarity for patterns of both lengths, but the direct measure yielded age differences favoring the young. For both ages and types of measures, the long patterns led to poorer learning than did the short patterns.     

Perceptual effect on motor learning in the serial reaction-time task

Although the Serial Reaction-Time Task has been an effective tool in studying procedural learning, there is still a debate as to whether learning in the task is effector-based, stimulus-based, or response-based. In this article, the authors contribute to this debate by contrasting response- and stimulus-based learning by manipulating them selectively and simultaneously. Results show that (a) participants learned response sequences in the absence of stimulus-specific perceptual sequence information but (b) not stimulus sequences without corresponding response information. In a third condition, response sequence and stimulus frequency information were in conflict, and each effect decreased learning in the other domain. Overall, our findings show that learning in these tasks is primarily motor-based, but it is also constrained by relatively salient perceptual information. Together with earlier findings in the literature, the findings also suggest a task and stimulus-arrangement-specific interaction between motor and perceptual learning, where relevance and salience of the specific information plays a crucial role.     

Recall and recognition of self-performed acts

Summary In Experiment 1, recall and recognition of 80 action phrases were compared under two encoding conditions: verbal and motor (performing the denoted acts). Memory performance was better under motor encoding than under verbal encoding, and more so in recognition than in recall. We assume that this finding is due to the item-specific effect of a specific motor component in the memory trace after enacting. In Experiments 2 and 3 we further investigated whether false-alarm rates are dependent on the motoric similarity of distractor items. The rate of false alarms was lower under motor encoding than under verbal encoding, but the motoric similarity of distractor items to list items did not influence the false alarms. The results were interpreted as support for the assumption that motor encoding enhances item-specific information in relation to verbal encoding, but that during verbal recognition the motoric quality of the depicted movement is not processed.