Event-related brain potentials during identification of tachistoscopically presented pictures.

In the present study in 20 healthy subjects, event-related potentials (ERPs) were used to investigate the identification of picture stimuli. Each of 36 landscape pictures and 36 scrambled pictures was presented by a tachistoscope repeatedly until the subject made an identification response. Presentation of one picture was finished after 12 exposures.

Standardized task strain and system response times in human-computer interaction.

Involuntary delays in human-computer interaction, for example, system response times (SRTs) can increase stress. In the present study, 40 college-age subjects were randomly divided into an 'incentive' and a 'non-incentive' group'. Subjects performed a computer task with SRTs of 0.

[Effect of system-related work interruptions in computer-assisted text processing: a field study].

To validate laboratory research findings on the stress inducing effects of system response time in human-computer interaction, a field study was performed at the central typing office of a bank. Simultaneous subject-oriented and object-oriented measures (questionnaires) of working properties were taken with a relatively high sampling rate over several days in addition to the ordinary business activities. In summary, the negative effects of system response times could also be observed in the real work setting, but were modified by subjective and situational factors which had not been considered in laboratory research yet.

[Effects of waiting times within simple problems: an analogy to waiting times in human-computer interaction].

The impact of forced intra-task waiting periods was evaluated in a laboratory study designed in analogy to forced waiting periods in human-computer interaction. Each task consisted of two lines of grouped capital letters (so-called Sterzinger lines) that had to be processed individually, separated by the experimental waiting period. The final response to both lines was taken after removal of the second line.

Experimental investigation of stress-inducing properties of system response times.

System response times are regarded as a major stressor in human-computer interaction. In two earlier studies short (2s) and long (8s) response times were found to have differential effects on psychological, subjective, and performance variables, but results did not favour either response time. Therefore, in another laboratory study with 48 subjects in four independent groups working at a stimulated computer workplace, system response times of 2, 4, 6 and 8s were introduced in the same error detection task as used before, during 3 training and 5 working trials of 20 min each, and the same physiological, subjective and performance measures were obtained.