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Biomedical subjects

R E Till

Publications and source records attributed to R E Till.

15 recordsLinked to original sources
PubMed1993

Is there really very rapid forgetting from primary memory? The role of expectancy and item importance in short-term recall.

In two experiments, subjects recalled one of two letter segments following a digit-filled retention interval. In Experiment 1, recall expectancy was manipulated by using precues that correctly informed or misinformed subjects concerning which letter segment would be tested for recall. In Experiment 2, item importance was varied by precuing one segment as important but requiring that the uncued segment be recalled first. Recall performance was very low under conditions of low expectancy and low segment importance, but the slopes of the retention functions did not demonstrate more rapid forgetting than under standard conditions. The previous observations of very rapid forgetting from primary memory may be a function of an elevated initial recall level in the earlier studies. Our retention functions were compared with predictions of the Estes perturbation model. The findings suggested that when secondary memory processes were reduced, forgetting order information from primary memory occurred at the same rate as that estimated on the basis of previous studies using the standard distractor task.

Adult↗
PubMed1987

Remembering left-right orientation of pictures.

In a study of recognition memory for pictures, we observed an asymmetry in classifying test items as "same" versus "different" in left-right orientation: Identical copies of previously viewed items were classified more accurately than left-right reversals of those items. Response bias could not explain this asymmetry, and, moreover, correct "same" and "different" classifications were independently manipulable: Whereas repetition of input pictures (one vs. two presentations) affected primarily correct "same" classifications, retention interval (3 hr vs. 1 week) affected primarily correct "different" classifications. In addition, repetition but not retention interval affected judgments that previously seen pictures (both identical and reversed) were "old". These and additional findings supported a dual-process hypothesis that links "same" classifications to high familiarity, and "different" classifications to conscious sampling of images of previously viewed pictures.

Adult↗
PubMed1987

Effects of cuing on short-term retention of order information.

In two experiments, subjects recalled one of two letter sequences following a digit-filled retention interval. Recall performance was increased by precues informing subjects which letter sequence would be tested, and the cuing advantage remained throughout 60-digit retention intervals. No improvement was found, however, for cues occurring after the letters but before the digits. The cuing effects were attributed to encoding, not rehearsal, processes and were explained by a version of the Estes perturbation model, which included a long-term storage component and a fixed perturbation probability.

Cues↗
PubMed1985

Verbatim and inferential memory in young and elderly adults.

Young and elderly adults were tested for inferential and verbatim recall from a list of unrelated sentences. All participants performed an encoding task (pleasantness rating or comprehension task) during input and, at test, attempted to answer a series of who questions. Half of the questions required verbatim recall; the other half could only be answered on the basis of an inference from an input sentence. For both types of question, young adults recalled more than elderly adults. Age differences were larger after pleasantness rating than after the comprehension task for both kinds of recall, suggesting that any benefits of comprehension encoding are not the result of specific attention to inferences but, more generally, result from the meaning integration or unique representation created for each sentence. Analyses of conditionalized recall (i.e., recall given a particular level of similarity between comprehension encoding and experimenter's subsequent inferential cues) showed that old adults were less likely than young adults to use inferential recall cues highly similar to their own comprehension responses.

Adult↗
PubMed1983

Age-related differences in memory for lateral orientation of pictures.

Two experiments examined memory for the lateral orientation of scenic pictures by young and elderly adults. In Experiment 1, an input list of pictures was followed by a test demanding discrimination between (a) targets versus reversed copies of input items, or (b) targets versus new pictures which verbally resembled input items. The age-related difference was reliably larger in the former task than in the latter. Experiment 2 compared incidental versus intentional acquisition of orientation under conditions of short (1 second) and long (5 second) presentation of pictures at input. With short presentation, though not with long presentation, intentional instructions reliably impaired orientation memory. With both presentation times, robust age-related differences were obtained. The results suggest an age-related deficit in truly non-intentional encoding of orientation, and pose a challenge for capacity theories of memory across the lifespan.

Adult↗
PubMed1981

On the locus of age differences in visual information processing.

Age differences in visual information processing were investigated in a study of monoptic backward masking. Young (18 to 22) and old (58 to 73) adults were tested in three experiments utilizing both a random visual noise and a pattern (fragments) mask, with two-letter combinations serving as target stimuli. Critical target duration needed to escape masking was measured at several mask durations in Exps. 1 and 2; critical interstimulus interval was assessed at several target durations in Exp. 3. With random noise as the mask, a small but reliable age difference was seen across the range of mask or target durations, supporting previous reports of age difference in peripheral processing. With the pattern mask as the masking stimulus, there was mixed evidence for age differences in central processing. Such age effects were clearest in Exp. 3 in which the role of luminance summation had been reduced. Control procedures in Exps. 1 and 2 tended to eliminate evidence for central masking. Results are discussed in terms of the magnitude of age differences in peripheral and central processing and in terms of procedural artifacts of previous research.

Adolescent↗
PubMed1980

Effects of label distinctiveness and label testing on recognition of complex pictures.

Two experiments examined the effects of label retrieval upon subsequent recognition of complex, scenic pictures. Contrary to past research, i.e., Bahrick and Boucher's 1968 study, retrieval of labels which accompanied pictures at input was associated with high recognition of "same-photo" (copy) cues but not false recognition of similar "same-scene" cues on a subsequent "photo" recognition test. The label-retrieval effect can be attributed to actual rehearsal of pictorial information and not to item selection. In addition, the beneficial effects of label retrieval did not vary with the informational content of the label itself, i.e., its power to distinguish between same-photo and same-scene items. However, the effects of label-type as well as label retrieval varied with recognition test instructions. In a "scene" recognition test, requiring recognition of both same-photo and same-scene items, effects of label-type were stronger than in the "photo" test, while effects of label retrieval were not significant. The results highlight the complexity of the relationships between label retrieval and picture recognition and suggest several factors which might determine such relationships.

Form Perception↗
PubMed1978

Age differences in peripheral perceptual processing: a monoptic backward masking investigation.

Peripheral processes in vision were investigated in two experiments involving monoptic backward masking with random noise. For young and old subjects, peripheral processing time (represented by stimulus onset asynchrony of target and mask) was characterized as a power function of target energy. Although processing time for both age groups showed a similar rate of decline with increasing target energy, old subjects processed targets more slowly at all energy levels. Results were independent of education, sex, and criterion differences between young and old. Target duration was related to critical interstimulus interval, such that stimulus onset asynchrony between target and mask was approximately constant for a given target energy within each age group. Evidence suggests that peripheral processing begins with target onset and that processing time is best characterized by a power function relating stimulus onset asynchrony of target and mask to target energy.

Adult↗
PubMed1978

Age-related differences in binocular backward masking with visual noise.

Peripheral processing, as defined by Turvey (1973), was investigated in a study of binocular backward masking involving random visual noise. For young (mean age 20.3 years) and old (mean age 55.4 years) adults, processing time (represented by stimulus onset asynchrony, SOA) was characterized as a power function of target energy (TE) (i.e., TEb x SOA = K). Over a wide range of target energy levels, processing time showed a similar rate of decline (similar exponent, b) for both age groups with increasing target energy. However, old subjects processed targets more slowly at all target energy levels (different constant, K), and this age difference was constant across all target energy levels. Results were independent of variables such as sex, education, response criterion, unmasked threshold, and method of determining stimulus onset asynchrony.

Adolescent↗
PubMedDate not supplied

Vasopressin analog (DDAVP) improves memory in human males.

One specific analog of arginine vasopressin, 1-desamine-8-D-arginine vasopressin (DDAVP), has been shown to improve learning and memory in humans. Healthy young male adult subjects treated with DDAVP demonstrated better memory for implicational sentences than did control subjects. The same treatment had no influence on women given the same memory task. These results suggest that DDAVP may have a sexually dimorphic effect on learning and memory.

Adult↗
PubMedDate not supplied

Sentence memory affected by vasopressin analog (DDAVP) in cross-over experiment.

DDAVP has been shown to facilitate memory, especially retrieval, in humans. Healthy young male adult subjects received DDAVP (60 micrograms) in a cross-over design with a one-week interval between sessions. Results indicated that DDAVP improved immediate memory during the first but not the second testing session, particularly for low-verbal subjects. Treatment with DDAVP also facilitated delayed (one-week) recall in the opposite group, a cross-over interaction that suggests a retrieval locus for the DDAVP effect. Furthermore, since DDAVP improved immediate memory more for low-verbal subjects and delayed memory more for high-verbal subjects, it appears that individual difference factors will be important in understanding the effects of vasopressin on memory.

Adult↗
PubMedDate not supplied

Dose-dependent effects of DDAVP on memory in healthy young adult males: a preliminary study.

Although several studies have demonstrated the efficacy of the vasopressin analog DDAVP in enhancing human memory, no previous study has reported the dose-response relationship of DDAVP to memory in healthy young adults. The present study was undertaken to explore the dose-response curve for DDAVP on recall of implicational sentences. Five doses of DDAVP (0, 5, 15, 30, and 60 micrograms) were administered intranasally to healthy young adult male volunteers. Results demonstrated a facilitation in cued recall after treatment with the 60-micrograms dose and a general impairment in recall after treatment with the 15-micrograms dose. These effects were independent of subject's weight, vocabulary ability, and concentration of salivary cortisol.

Adolescent↗
PubMedDate not supplied

Age differences in picture memory with resemblance and discrimination tasks.

Previous research on recognition memory has examined age-related effects on knowledge of the difference between lures and input items (e.g., false alarm rate), but has not examined age-related effects on knowledge of the resemblance between lures and input items. In the present experiment, subjects in two age groups (means = 19.3 years and 63.8 years) saw a list of scenic pictures, followed by a recognition test containing same-photo items, each a copy of an input picture, same-scene items, each from the same original scene as an input picture, and different-scene items. The task was to categorize each test picture as same-photo, same-scene or different-scene. There were no reliable age differences on standard recognition measures of hits and false alarms. However, younger subjects were better than older subjects at detecting the resemblance between same-scene items and input items, although this age difference was less apparent when the initial encoding provided experience with resemblance detection. The results have implications regarding age effects in picture memory and in recognition memory generally.

Adolescent↗