Suchergebnisse

An investigation was conducted to determine if performance on a keeping-track task could be enhanced by redundantly coding the displayed information channels that were being updated. At set intervals, the subject was interrogated about the status of any one of the information channels. The information consisted of numbers, colors, or numbers on a colored background, the last being the redundantly coded material. The three variables studied were channel value, payoff ratio, and coding condition. Results indicated that redundant coding did not aid performance; rather, it provided the subjects extra cues and increased the number of strategies that were used. As in previous studies, selective attention to the high-valued channels was a function of channel value and payoff ratio.

Performance in keeping track of several channels of information was investigated as a function of payoff ratio, display format, stimulus on-time, load, and channel payoff value in a 4 × 2 × 2 × 2 × 2 mixed design. Each of 32 subjects was instructed to keep track of the status of a six-or ten-channel display. On alternate trials, a subject either was presented with a new piece of information or was interrogated about the present status of a channel. Analysis of the results indicated significant payoff-ratio, format, stimulus on-time, load, and value effects, as well as a significant load × value interaction. Results suggested that the greater the load on the operator and the greater the disparity between high- and low-valued information, the more likely selectivity of information is to occur. In addition, the probability of a correct response was investigated as a function of the time the information had to be retained and of the independent variables. Applications of the results to display monitoring contexts are discussed.

A search of the psychological, technical, and promotional literature was conducted to compile information relevant to key, keyboard, and operator characteristics. The most recent and significant articles were discussed and evaluated. Where possible, general conclusions have been drawn to aid the keyboard designer.

An optional stopping experiment was performed in which the subject had to decide not only how much information to gather prior to making a two-choice decision, but also which of three information sources to consult. The cost of consulting these sources was varied systematically, with each source having a known, fixed diagnosticity. Two loss structures were used: (1) penalty for miss = penalty for false alarm, and (2) penalty for miss = 3 × penalty for false alarm. Results indicated subjects bought too little information relative to an optimal Bayesian model. The subjects indicated a reluctance to expend the resources required to obtain the best information available. Although subjects responded to the loss variables in the appropriate direction, they did not respond with sufficient magnitude to be mathematically optimal. Future research areas are suggested.