Biomedical subjects

P C Amrhein

Publications and source records attributed to P C Amrhein.

8 recordsLinked to original sources

PubMed1999

Locus of control and the age difference in free recall from episodic memory.

The authors investigated the relation of locus of control (LOC) to age differences in free-recall memory performance. Older and younger participants completed P. C. Duttweiler's (1984) Internal Control Index (ICI) and subsequently performed free-recall memory tasks. Compared with the younger participants, the older participants exhibited poorer recall with more intrusions and uncorrected repetition errors as well as reduced categorical clustering. For the older participants with less internal LOC, recall proportion and item-pair associative recall clustering were lower than for the older participants with more internal LOC. By contrast, the younger participants did not exhibit any LOC effects in their recall performance. The results suggest that a differential memory organization deficit may underlie the age differences in free recall among individuals varying in LOC when they are performing an intentional learning task. This deficit is discussed in terms of a reduced-inhibition account of cognitive aging.

Adult↗

PubMed1994

Temporal invariance for picture-word translation: evidence from drawing-writing and naming-reading tasks.

In two experiments, picture-word processing was investigated using graphic (drawing-writing) and verbal (naming-reading) production tasks. In both experiments, the subjects drew a picture or wrote a word upon presentation of a picture or a word stimulus. Additionally, the subjects in Experiment 2 named a picture or read a word stimulus. Production onset latency was assessed. In both experiments, drawing production was initiated more slowly than was writing production. In Experiment 2, graphic production was initiated more slowly than was verbal production. Equivalent latency increases were found for cross-modality trials (e.g., drawing a picture given a word stimulus) relative to within-modality trials (e.g., drawing a picture given a picture stimulus), independent of stimulus modality (word or picture), production modality (word or picture), or task (graphic or verbal production). These results strongly support a mathematical model which incorporates temporal invariance for pictures and words concerning encoding, cross-modality transfer, and retrieval.

Attention↗

PubMed1993

The time it takes elderly and young individuals to draw pictures and write words.

Twenty elderly and 20 young Ss drew pictures or wrote words for picture or word stimuli. Elderly Ss had slower response initiation than young Ss, especially when drawing. Beyond this, both age groups processed picture and word stimuli similarly. Elderly and young Ss exhibited equivalent latency increases for cross-modality trials (e.g., draw a picture given a word) over within-modality trials (e.g., draw a picture given a picture), regardless of stimulus or task modality. Strong support was found for a mathematical model of these results, which assumes age-related additive slowing for input and output subprocesses but age invariance for a cross-modality transfer subprocess. However, regressing elderly on young whole-condition latencies indicated general, multiplicative slowing: a discrepancy that questions the utility of the global Brinley plot procedure in revealing the nature of age-related slowing.

Adolescent↗

PubMed1991

Age differences in the maintenance and restructuring of movement preparation.

In 2 experiments, elderly and young subjects performed simple reaction time, choice reaction time, and movement plan restructuring tasks, using a stimulus precuing paradigm. In Experiment 1, the precue display (200 ms) and preparation interval (250, 500, 750, or 1,000 ms) were experimentally determined. In Experiment 2, the precue display interval was subject determined. For the restructuring task, the precue specified the response on 75% of the trials, enabling movement plan preparation with respect to movement parameters of arm and direction. On remaining trials, the precue incorrectly specified the response, requiring movement plan restructuring. Elderly, but not young, subjects restructured a movement plan for direction more quickly than for arm or for both parameters. These findings indicate that elderly individuals have poorer movement plan maintenance for direction than for arm and thus exhibit functional change in movement preparation processes relative to young individuals.

Adult↗

PubMed1989

Theoretical analysis of the cognitive processing of lexical and pictorial stimuli: reading, naming, and visual and conceptual comparisons.

This article reviews the research literature on the differences between word reading and picture naming. A theory for the visual and cognitive processing of pictures and words is then introduced. The theory accounts for slower naming of pictures than reading of words. Reading aloud involves a fast, grapheme-to-phoneme transformation process, whereas picture naming involves two additional processes: (a) determining the meaning of the pictorial stimulus and (b) finding a name for the pictorial stimulus. We conducted a reading-naming experiment, and the time to achieve (a) and (b) was determined to be approximately 160 ms. On the basis of data from a second experiment, we demonstrated that there is no significant difference in time to visually compare two pictures or two words when size of the stimuli is equated. There is no difference in time to make the two types of cross-modality conceptual comparisons (picture first, then word, or word first, then picture). The symmetry of the visual and conceptual comparison results supports the hypothesis that the coding of the mind is neither intrinsically linguistic nor imagistic, but rather it is abstract. There is a potent stimulus size effect, equal for both pictorial and lexical stimuli. Small stimuli take longer to be visually processed than do larger stimuli. For optimal processing, stimuli should not only be equated for size, but should subtend a visual angle of at least 3 degrees. The article ends with the presentation of a mathematical theory that jointly accounts for the data from word-reading, picture-naming visual comparison, and conceptual-comparison experiments.

Adult↗

PubMed1988

Aging and the restructuring of precued movements.

A precue paradigm was used to examine the time it takes to restructure a planned motor response. Two groups of subjects, a young group and an elderly group, performed an aiming task in which 75% of the trials involved no change of movement parameters. On remaining trials, subjects had to change one or more of the movement parameters. Elderly subjects had slower reaction times (RTs), movement times, and made more errors in both conditions. Elderly subjects had proportionally longer RTs overall, independent of restructuring a movement plan. Preparation of arm and direction also exhibited a proportional increase in RT. However, differential aging effects were found for preparation of extent. Elderly subjects were slower preparing short movements compared with long movements, whereas young subjects showed the opposite trend. These results suggest that with advancing age, operations concerned with movement-plan restructuring for arm and direction undergo change in processing rate, whereas operations for extent undergo more extensive alteration.

Adult↗

PubMed1988

Age differences in bimanual coordination.

A bimanual coordination experiment was conducted in which two groups of 10 male and female participants, elderly (67 to 75 years of age) and young (21 to 25 years of age), produced unimanual, bimanual symmetrical (equal extent amplitude), and bimanual asymmetrical (unequal extent amplitude) movements. In addition to an overall increase in performance latency, the elderly group exhibited a linear increase in response initiation (RT) with increases in task complexity similar to that of the young group. However, the elderly participants showed a proportional increase over the young participants in response execution latency (MT). Further, the elderly group had a slower RT for short movements than long movements, an effect not found in the young group. Compared with the young participants, the elderly participants showed greater asynchrony in response initiation of bimanual movements; increased inability to subsequently compensate during response execution also resulted in a greater asynchrony in response termination. These results suggest specific aging deficits in bimanual coordination processes.

Adult↗

PubMedDate not supplied

Evidence of direction loss in elderly movement preparation is not due to spatial orienting effects.

Twenty elderly and young subjects performed matched movement plan restructuring and spatial orienting tasks. In the restructuring task, a precue stimulus was presented for 200 ms, followed by a preparation (PI; 250, 500, 1000, or 2000 ms), and the target stimulus. On 75% of the trials, the precue specified the aiming movement response enabling movement plan preparation concerning parameters of arm and direction. On 25% of the trials, the precue incorrectly specified the response requiring movement plan restructuring. The orienting task assessed shifts in perceptual localization of the precue and target stimuli for restructuring task conditions. At PIs of 1000 and 2000 ms, elderly, but not young, subjects restructured a movement plan for direction more quickly than for arm or both parameters. Spatial orienting shifts did not account for these effects.

Adolescent↗