Suchergebnisse

Communication between ground controllers and pilots was simulated in a short-term memory task in order to explore sources of memory errors in the air traffic control system. As expected from prior short-term memory research, two major determinants of error probability were (1) amount of information that the pilot has to process in a given time and (2) retention interval between the time information is transmitted from the controller and the time it is acted on (recalled) by the pilot. Additionally, the manner of encoding numerical information was varied. The result of this manipulation indicated that, as suggested by recent research in cognitive psychology, the current information-encoding scheme has substantial room for improvement in terms of minimizing memory failure.

Performance in a memory-span task using eight-letter sequences was explored as a function of presentation rate (.5, .75, 1.0, 2.0, and 3.0 sec/item) and presentation mode (visual, auditory, simultaneous visual and auditory, and mixed visual and auditory). Results indicate that performance in the mixed mode was inferior to the other three modes, but the other modes did not differ from each other. As presentation rate decreased, performance improved. These results are consistent with current theories of memory and indicate that the mode in which alphanumeric information is displayed is unimportant provided the modes are not mixed.

Three experiments were performed that compared recall for synthetic and natural lists of monosyllabic words. In the first experiment, presentation intervals of 1, 2, and 5 s per word were used. Although free recall was consistently poorer overall for the synthetic lists at all presentation rates, the decrement for synthetic stimuli did not increase differentially with faster rates. In a second experiment, zero, three, and six digits were presented visually for retention prior to free recall of each spoken word list in a preload paradigm. Fewer subjects were able to correctly recall all of the digits for the six-digit list than the three-digit list when the following word lists were synthetic. The third experiment required ordered recall of lists of natural and synthetic words. Differences in ordered recall between the synthetic and natural word lists were substantially larger for the primacy portion of the serial position curve than the recency portion. These results indicate that difficulties observed in the perception and comprehension of synthetic speech are due, in part, to increased processing demands in short-term memory.

When individuals undertake to memorize long sequences of items, they show a strong tendency to break the sequences into smaller subgroups. This type of spontaneous grouping can be called "natural" grouping. This report reveals that certain specific grouping patterns are spontaneously utilized significantly more often than others for various particular sequence lengths. Furthermore, those persons who employ these "natural" grouping patterns obtain significantly better recall results. The most "natural" subgroup size was found to be three digits with two digits being the next most "natural." These findings should be useful for any application in which number codes are used (telephone numbers, license plates, stock numbers, etc.).

Two laboratory experiments evaluated short-term retention of information from verbal and symbolic signs after following verbal (auditory mode) and pictorial (visual) forms of interfering activities. A differential interference effect was observed consistent with the .dualcoding hypothesis. From a practical viewpoint, neither type of Sign appeared superior in terms of its likely retention in short-term memory by drivers.