Influence of auditory or visual warning on visual reaction time with variations of subjects' alertness

The purpose of the study was to determine the effect of visual and auditory warning on visual reaction time with variations of subjects' alertness. An experimental group of 30 subjects was tested with an auditory or visual warning signal; foreperiods lasted 3, 2, and 4 sec. Reaction time was shorter as alertness improved and with an auditory warning signal. Comparable measures in a control group showed that visual reaction time was shorter when an auditory warning signal was used.     

Sequential effects in auditory choice reaction time tasks

This paper concerns sequential effects in choice reaction time tasks. Performance in two interleaved auditory tasks was examined, and two general types of sequential effects were revealed. First, a response repetition effect occurred: Subjects were facilitated in responding when both the stimulus and the response were immediately repeated. Generally, it appeared that subjects were operating according to the bypass rule—that is, repeat the response if the stimulus or some aspect thereof is repeated from the preceding trial; otherwise, change the response. In addition, the experiment also revealed a second type of sequential effect, known as a task-switching effect. Subjects were overall slower to respond when the task changed between adjacent trials than when there was no task change. A final result was that subjects were markedly impaired when the stimulus changed but the same response had to be repeated. This finding has been reported elsewhere when purely visual tasks have been used. Hence, it seems that particular difficulties arise, in such sequential testing situations, when type-distinct stimuli are grouped into the same response categories.     

Effects of variations in force on fractionated reaction time in simple and choice conditions

The present study examined the effects of force output on fractionated reaction time under simple and choice conditions. 20 subjects were required to react and produce a designated force as soon as possible after a visual stimulus. Five different levels of force were 10, 30, 50, 70, and 90% of the maximum grip strength of the subjects. Analysis showed that reaction time (RT) changed as a function of force in both conditions, with the longest RT occurring at the 70% condition. The same pattern was also evident for premotor time. These findings suggest that the changes in RT with increases in force are mediated predominantly by central rather than peripheral processes.     

Effect of locus of warning tone on auditory choice reaction time

Forty Ss pressed a left- or right-hand key depending on the ear in which they heard a 500-Hz stimulus tone. Half of the Ss were instructed to press the key on the same side as the ear stimulated (corresponding condition), while the other half pressed the key on the opposite side (noncorresponding condition). A 200-Hz warning tone preceded the stimulus tone by either 200 or 400 msec. The warning tone was presented to the left ear, the right ear, or to both ears in a predetermined random sequence. The locus of the warning tone affected RT on noncorresponding trials but not on corresponding trials. The effect consisted of a significant slowing of information processing on trials where the warning tone was contralateral to the response. Results were explained in terms of an initial tendency to respond toward the source of the warning tone.     

Ultradian cyclicity in auditory and visual reaction time during long performance

24 subjects were tested to check the hypothesis proposed by Kleitman about a "basic rest-activity cycle". Reaction time tasks were delivered at 10-min. intervals for 320 min. Spectral density function analyses showed no significant periods within the limits of the cycle. Discussion concerns fulfilling assumptions of spectral analysis and Fisher's test.     

Effects of redundant auditory stimuli on reaction time

Auditory redundancy gains were assessed in two experiments in which a simple reaction time task was used. In each trial, an auditory stimulus was presented to the left ear, to the right ear, or simultaneously to both ears. The physical difference between auditory stimuli presented to the two ears was systematically increased across experiments. No redundancy gains were observed when the stimuli were identical pure tones or pure tones of different frequencies (Experiment 1). A clear redundancy gain and evidence of coactivation were obtained, however, when one stimulus was a pure tone and the other was white noise (Experiment 2). Experiment 3 employed a two-alternative forced choice localization task and provided evidence that dichotically presented pure tones of different frequencies are apparently integrated into a single percept, whereas a pure tone and white noise are not fused. The results extend previous findings of redundancy gains and coactivation with visual and bimodal stimuli to the auditory modality. Furthermore, at least within this modality, the results indicate that redundancy gains do not emerge when redundant stimuli are integrated into a single percept.     

Visual and auditory choice reaction times

Choice reaction times are measured for three values of a priori signal probability with three well-practiced observers. Two sets of data are taken with the only difference being the modality of the reaction signal. In one set of conditions it is auditory, in the other, visual. The auditory reaction times are faster than the visual and in addition several other differences are noted. The latency of the errors and correct responses are nearly equal for the auditory data. Error latencies are nearly 30% faster for the visual data. Non-stationary effects, autocorrelation between successive latencies and non-homogeneous distribution of errors, are clearly evident in the visual data, but are small or non-existent in the auditory data. The data are compared with several models of the choice reaction time process but none of the models is completely adequate.     

Useful visual field in patients with schizophrenia: a choice reaction time study

This study examined the size of the useful visual field in patients (9 men, 6 women) with schizophrenia. A choice reaction task was conducted, and performances at 2.5, 5, 7, 10, and 25 degrees in both visual fields were measured. Three key findings were shown. First, patients had slower choice reaction times (choice RTs) than normal controls. Second, patients had slower choice RTs in the right visual field than in the left visual field. Third, patients and normal controls showed the same U-shaped choice RT pattern. The first and second findings were consistent with those of other studies. The third finding was a clear indication of the patients' performance in peripheral vision, and a comparison with normal controls suggested that there was no difference in the size of the useful visual field, at least within     

Effects of auditory input in individuation tasks

Under many conditions auditory input interferes with visual processing, especially early in development. These interference effects are often more pronounced when the auditory input is unfamiliar than when the auditory input is familiar (e.g. human speech, pre‐familiarized sounds, etc.). The current study extends this research by examining how auditory input affects 8‐ and 14‐month‐olds’ performance on individuation tasks. The results of the current study indicate that both unfamiliar sounds and words interfered with infants’ performance on an individuation task, with cross‐modal interference effects being numerically stronger for unfamiliar sounds. The effects of auditory input on a variety of lexical tasks are discussed.