Content memory and temporal memory for actions in survivors of traumatic brain injury.

Memory for performed actions, a rehearsal-independent form of memory, was compared to verbal memory in 30 survivors of traumatic brain injury (TBI) and 30 demographically matched controls. Subjects were tested on recognition and recall memory for the content of recently performed actions in the laboratory, as well as the ability to reconstruct the temporal order in which the actions were performed. Each subject performed actions under incidental and intentional memory instructions. Half of the subjects performed 12 actions, the other half 24 actions, with an equal number of usual and unusual actions in each list. Verbal memory was assessed with paired-associate and temporal order tests. Although recall was more proficient overall for the control compared to the brain-injured subjects on both content and temporal memory for actions, memory for actions was better than verbal memory in both groups. Both groups performed better overall on the short compared to the long list of actions and recalled unusual actions better than usual actions. The rehearsal-independent nature of action memory was supported, with no advantage for the intentional instruction. It is proposed that a retrieval deficit may be in part responsible for deficits in memory for actions following TBI. However, preserved ability to benefit from the abundant contextual cues available through motor actions may account for the better recall of actions compared to words.

Adult age differences in temporal memory for cyclic actions.

Adult age differences in temporal memory for bipolar or cyclic actions were investigated in three experiments. Cyclic actions are ones that have opposite poles in regard to their effect on an object (e.g., opening and closing a purse). For such actions, the critical memory function is to remember which pole occurred last. Temporal memory was tested by having subjects judge which component of a series of bipolar actions had been performed more recently (e.g., opening or closing a purse). Recency judgments were found to be as accurate under incidental memory conditions as they were under intentional memory conditions for both young and elderly adults. The accuracy of recency judgments was less for bipolar actions performed in three cycles than for bipolar actions performed in one cycle for both young and elderly adults. Adult age differences in the accuracy of recency judgments were found to be negligible.

Adult age differences in short-term memory and subsequent long-term memory for actions.

Short-term memory for actions was investigated for young adult and elderly adult subjects with the Brown-Peterson procedure at retention intervals of 0 and 15 s. The short-term memory trials were followed by the long-term recall of the prior to-be-remembered actions. The 15-s retention interval was filled either with no activity or with 1 of 3 different interfering activities. Verbal interference had little effect on short-term memory at either age level. Actions performed in the interval either by the subjects or by the experimenter produced significantly lower recall scores at each age level, with the decrement being more pronounced for the elderly than for the young subjects. The long-term memory results indicated that successful short-term recall enhanced later long-term recall, regardless of age level.

Variation in external context and adult age differences in action memory.

Adult age differences were determined for the memory and retention of the content of actions. Variation in the physical context from the time of performance of the actions to the time of testing for their memory had no effect for either young or elderly adult subjects on the recall or the recognition of the actions either shortly after acquisition or 24 hours later. Both young and elderly subjects showed significant forgetting of actions over a 24-hour retention interval as measured by recall.

Effects of short-term retrieval on adult age differences in long-term recall of actions.

In Experiment 1 young and elderly subjects either recalled or repeated after every block of 4 actions, whereas control subjects received neither interpolated short-term recall nor action repetition. On a later long-term memory test, experimental subjects, regardless of age or condition, recalled slightly more actions than control subjects. In Experiment 2 young adult and elderly subjects received 12 short-term memory trials in which 2 actions were performed on each trial, but only 1 was cued for recall after a brief retention interval filled with a distracting activity. On a later long-term memory test for the actions performed on the short-term trials, both young and elderly subjects recalled significantly more previously cued than noncued actions. The Age X Cuing Condition interaction was negligible. Prior retrieval of actions appears to enhance later recall regardless of age but seemingly only when prior retrieval requires considerable cognitive effort (as in Experiment 2).

Adult age differences in memory for massed and distributed repeated actions.

Adult age differences in memory for actions were investigated in 2 experiments in which actions were repeated with massed or distributed spacing. In Experiment 1, subjects received a mixed series of actions, half performed once, the others twice, with repetitions either massed or distributed. Young subjects recalled more actions than did the elderly, and more distributed actions were recalled than massed actions. However, the Age X Spacing interaction was not significant. A probable inhibitory mechanism with a mixed list was avoided in Experiment 2 by use of unmixed series. Actions were performed once only, twice only in massed repetitions, or twice only in distributed repetitions. The age difference was significant, and more actions were recalled in the distributed condition than in either of the other conditions, the results of which did not differ from one another. The Age X Conditions interaction was negligible. These results imply that elderly subjects are as likely as young subjects to encode contextual information while performing actions.

Age, self-assessed health status, and cognition.

Data from a recent project involving 362 adults ranging from 20 to 79 years of age were reanalyzed to examine the effects of statistical control of self-assessed health status on the age trends in several measures of cognitive functioning. The major result was that the age trends were virtually identical with, and without, control of the health-status variable. Implications of the views that the lack of health influences was due to a narrow range of health status or to insensitive assessment of health status were discussed.

Effects of prior retrieval on adult age differences in long-term recall of activities.

The beneficial effects of prior short-term retrieval on the later long-term recall of activities were tested for both young adult and elderly adult subjects. For a series of 12 activities, short-term recall tests occurred after each block of 2, 4, or 6 activities. Relative to a control condition receiving no interpolated short-term tests, long-term recall was higher overall for the interpolated recall conditions at both age levels. However, the magnitude of the age-related deficit was unaffected by the various conditions. The greatest increment in long-term recall occurred for the groups receiving short-term tests after every four activities. The optimal benefit of prior retrieval as a mnemonic seems to come from conditions that demand some degree of cognitive effort as well as a moderately high level of successful short-term retrieval. In addition, a significant age-related deficit in recall was found for a short list of 6 activities as well as for the longer list of 12 activities.

Temporal memory and content memory for actions: adult age differences in acquisition and retention.

Young adult and elderly adult subjects were tested under incidental memory conditions for recognition memory of content and temporal memory for the order of a series of actions performed in the laboratory. The tests were conducted both shortly after completion of the series and 24 hours later, with different sets of actions tested on each occasion. Recognition memory of content showed no forgetting for the young subjects, but significant forgetting for the elderly subjects. Memory for temporal information was substantially greater for the young subjects than for the elderly subjects. Both age groups showed substantial forgetting of temporal information over the 24-hour retention interval.

Utilization of path-analytic procedures to investigate the role of processing resources in cognitive aging.

Data from two batteries of tests administered to 129 and 233 adults, ranging from 20 to 79 years of age, were analyzed to explore the viability of models postulating that age differences in the quantity or efficiency of processing resources are responsible for many of the age differences observed in cognitive functioning. Path-analysis procedures were used to estimate the direct and indirect, or resource-mediated, effects of age on cognitive performance. Results, with simple speed and memory measures serving as the indexes of processing resources, indicated that there was little support for a strong resource model, and evidence derived from a weak resource model suggested that resource-mediated contributions to age differences are small, relative to those not mediated by processing resources.

Instructional variation and adult age differences in activity memory.

Recall of a series of 12 activities was compared for young and elderly subjects performing under four instructional conditions: incidental memory, standard intentional memory, intentional-emphasis, and interpolated recall (intermediate recall tests after every three activities had been performed). Relative to the incidental memory condition, superior recall was found for subjects in the intentional-emphasis and intentional-interpolated recall conditions. An age-related deficit in recall was found, but the Age X Instructional Condition interaction was not significant. Instructional variation was also found to affect temporal memory scores for the order in which the activities has been performed. An age-related deficit in temporal memory proficiency was found for all conditions except that of interpolated recall. On the other hand, instructional variation had a negligible effect on performance scores for the 12 specific activities.

Temporal memory over the adult lifespan.

Performances of noncollege student young adults, middle-aged adults, and elderly adults were contrasted on word temporal memory and paired-associate learning tasks. A comparison group of college-student subjects was also evaluated on each task. Significant effects for age variation were found for each task. The age sensitivity for temporal memory conflicts with one of the criteria commonly established for determining the automaticity of a memory task. In addition, moderately high positive correlations were found for each age group between word temporal memory scores and paired-associate learning scores, implying the involvement of effortful processes over the adult lifespan in word temporal memory.

Frequency-of-occurrence memory over the adult lifespan.

As part of a large scale normative study involving a number of cognitive tasks, 233 subjects, all noncollege students ranging in age from 20 to 79 years, performed two frequency judgment tasks. A modest, but statistically significant, age-related deficit was found, with the decrement in proficiency being largest from middle to late adulthood.

Activity duration and adult age differences in memory for activity performance.

Young and elderly subjects performed a series of activities that varied in the duration of their performances (45 s, 90 s, and 180 s). Duration was found to have a negligible effect on the subsequent recall of the activities and on the magnitude of the age deficit in recall. Operationalization of the program for performing an activity seems essential for establishing a memory trace of that activity's performance, but the duration of performing that activity seems to yield no further enhancement of that trace.

Adult age differences in memory for motor versus cognitive activities.

Young and elderly participants performed on a series of 12 sustained activities (3 minutes each) under either incidental or intentional memory conditions regarding subsequent recall of those activities. Half of the activities were primarily motor in nature, half primarily cognitive. A significant overall age deficit was found for recall. Most important, in contrast to the contextual support hypothesis, the age deficit was as pronounced for motor activities as for cognitive activities. For both kinds of activities, incidental memory was as proficient as intentional memory.

Memory for topics of conversation: adult age differences and intentionality.

Young adults and elderly adults received a series of topics for discussion, followed by a recall test of the topics per se and a recognition memory test of the questions asked during the conversations. Half of the participants in each age group were forewarned of the subsequent recall test (intentional memory); the remaining participants were not forewarned (incidental memory). Null effects for instructional variation were found at both age levels for all memory scores. For recall, an age difference, favoring young adults, was found. However, no age difference was found for either the recognition of old questions as old or the recognition of new questions as new. The results were interpreted in terms of an age deficit for the retrieval of memory traces established by the comprehension of conversational content.

Frequency judgments by young and elderly adults for relevant stimuli with simultaneously present irrelevant stimuli.

Young and elderly adults judged the frequency of occurrence of right words (relevant information) and wrong words (irrelevant information) that had varying numbers of exposure in a multiple-item recognition learning study list. Elderly adults gave lower frequency values to right words than did young adults but only when each right word was accompanied by more than one wrong word in the study list. This outcome was attributed to an age difference in the distractability created by the presence of irrelevant sources of information. By contrast no age difference was found for the frequency judgments given to wrong words, words that presumably are processed at a superficial level by elderly adults as well as young adults.

Adult age differences in frequency judgments of categorical representations.

Adult age differences were examined for relative frequency judgments on a task in which categories had either zero, one, three, or five instances in a study list. Judgments required selecting from pairs of category names which member had the greater representation of instances in the prior list. Contrary to the results obtained in earlier studies using a task in which discrete events vary in frequency of occurrence, an age difference favoring young adults over elderly adults in accuracy of frequency judgments was found for categories. Neither instructional variation (incidental learning vs. intentional learning) nor variation in priming (cuing vs. noncuing with the list of categories prior to the study trial) yielded either main effects or interaction effects with age. The results were interpreted in terms of an age deficit in either the storage or the retrieval of memory traces of category names established by the automatic elicitation of implicit associative responses to instances of taxonomic categories.

Adult age differences in memory for sex of voice.

Young and older adults (elderly in Experiment 1 and middle-aged in Experiment 2) received successive sentence recall tasks for which one-half of the sentences were read in a male voice and one-half in a female voice. With regard to the sex of voice component, the first task was administered under incidental learning conditions and the second under intentional learning conditions. With regard to sentence content, both tasks were administered under intentional learning conditions. The results indicated that encoding voice information is a cognitively effortful, age sensitive process. For older adults, both elderly and middle-aged, enhanced voice encoding under the intentional condition, relative to the incidental condition, was accompanied by a significant decrement in sentence recall. For young adults, the trade off effect was not large enough to reach statistical significance. The age difference apparently reflects the diminished processing capacity of older adults relative to young adults, with the decrease in capacity having its onset by middle age.

Adult age differences in memory for modality attributes.

Young and elderly subjects performed on two memory tasks. The first task involved recognition of word content and identification of each word's sex of voice in the study list. An additional independent variable consisted of intentional versus incidental learning instructions. An age difference favoring young adults was found for both word recognition and sex of voice recognition, confirming earlier evidence found with a more difficult sentence recall task. Comparable age deficits were found on the second task involving word recognition and identification of each word's case format in the study list. Encoding of modality attributes does appear to be an effortful process and is susceptible to age deficits. However, contrary to the age differentiation hypothesis, the cross-task correlation between modality recognition scores was no greater for elderly adults than for young adults.