Reaction time,movement time,and intelligence

Speed of information processing is measured in terms of reaction time (RT) and movement time (MT) to five stimulus displays which differ in the amount of information transmitted, over a range from 0 to 3 bits of information. RT, but not MT, increases as a linear function of the number of bits in the stimulus display. RT and MT show reliable individual differences which are significantly correlated with intelligence as measured by Raven's Standard Progressive Matrices.     

Reaction time to the offset of brief auditory stimuli

An earlier investigator has found that the time at which the offset of a stimulus is perceived depends on the time of stimulusonset, rather than on the time of stimulus offset, for stimuli briefer than a critical duration of the order of 100 msec. In an attempt to determine whether this effect extends to reaction time (RT), we have determined RT to the offset of brief noise bursts. RT was found to be essentially constant as a function of stimulus duration. Thus, RT to stimulus offset appears not to be related to the time of perception of offset, as determined in the earlier investigations.     

Reaction times to auditory and visual stimulation in schizophrenic and normal subjects

An experiment carried out to determine the relation between auditory and visual reaction times suggested that when the general level of response is slow visual RTs are faster than auditory, and that the reverse is the case when the level of response is fast. Thus most normal subjects have an auditory RT faster than visual, and most schizophrenics the reverse. However, the difference between auditory and visual RTs does not appear to depend directly on schizophrenic pathology except in so far as this is a factor in the general slowness of reaction time.     

Reaction time and movement time after active and passive smoking

Reaction time and movement time were studied following active and passive smoking in two groups of 20 women. All subjects were tested under a clean air and smoky air condition and the results showed that, while there was no difference between groups for either measure in the clear air condition, the active smokers had faster reaction time and movement time in the smoky air condition. Smoky air had no significant effect on the responses of the passive smoking group.     

Bilateral saccadic eye movements and tactile stimulation,but not auditory stimulation,enhance memory retrieval

Recent research has shown superior memory retrieval when participants make a series of horizontal saccadic eye movements between the memory encoding phase and the retrieval phase compared to participants who do not move their eyes or move their eyes vertically. It has been hypothesized that the rapidly alternating activation of the two hemispheres that is associated with the series of left–right eye movements is critical in causing the enhanced retrieval. This hypothesis predicts a beneficial effect on retrieval of alternating left–right stimulation not only of the visuomotor system, but also of the somatosensory system, both of which have a strict contralateral organization. In contrast, this hypothesis does not predict an effect, or a weaker effect, on retrieval of alternating left–right stimulation of the auditory system, which has a much less lateralized organization. Consistent with these predictions, we replicated the horizontal saccade-induced retrieval enhancement (Experiment 1) and showed that a similar retrieval enhancement occurs after alternating left–right tactile stimulation (Experiment 2). Furthermore, retrieval was not enhanced after alternating left–right auditory stimulation compared to simultaneous bilateral auditory stimulation (Experiment 3). We discuss the possibility that alternating bilateral activation of the left and right hemispheres exerts its effects on memory by increasing the functional connectivity between the two hemispheres. We also discuss the findings in the context of clinical practice, in which bilateral eye movements (EMDR) and auditory stimulation are used in the treatment of post-traumatic stress disorder.     

Simultaneous auditory and tactile information processing

Subjects were required to perform perceptual tasks when stimuli were presented simultaneously in the auditory and tactile modalities and when they were presented in one of the modalities alone. The results indicated that when the demands on cognitive processes are small, auditory and tactile stimuli presented simultaneously can be processed as well as when stimuli are presented in only one modality. In a task which required a large amount of cognitive processing, it became difficult for subjects to maintain high levels of performance in both modalities and the distribution of attention became an important determinant of performance. The data were consistent with a theory that cognitive, but not perceptual, processing is disrupted when subjects have difficulty performing two perceptual tasks simultaneously.     

Reaction time and movement time as measures of stimulus evaluation and response processes

Reaction time has been divided into the time to initiate a response (RT) and the time to execute the motor response (MT) in many chronometric studies of intelligence. Our purpose was to determine which cognitive processes are reflected by RT and MT. To accomplish this, the latency of the P300 wave of the event-related potential was recorded concurrently with RT and MT measures in three experiments. P300 latency reflects the duration of stimulus evaluation relatively independently of response processes. In the first experiment, a Sternberg memory task was employed to manipulate stimulus classification requirements. In the second, the subjects' emphasis on either speed or accuracy of responding was examined during a task that also manipulated stimulus evaluation time. In the third experiment, a Stroop-like task was used to examine response processes. RT and P300 latency varied with manipulations of stimulus evaluation time, whereas MT varied with difficulty of motor execution. MT was also affected by stimulus classification processes. Both RT and MT were sensitive to processes involved in response bias and preparation. The possibility that the correlations of RT and MT with measures of intelligence are due to effects on a common stage of information processing cannot be rejected in the light of these results.     

Reaction time and movement time measured in a key-press and a key-release condition.

Reaction time (RT) and movement time (MT) are measured in two conditions, a key-press and a key-release condition. The latter makes a greater demand on perceptual feedback than the former. RT increases in the key-release condition and a fraction of MT denoted key-press time (KT) decreases in the key-press condition. It is argued that KT of a response button in the simple reaction-time experiment may serve as a proper measure of the motor component. The foreperiod prior to onset of the reacting stimulus affects RT, KT, and MT, suggesting that preparatory set or expectancy influences both the perceptual and motor components of simple human performance. The results indicate that the relation of RT and MT depends upon methodological conditions.     

Reaction time,movement time,and intelligence: A replication and extension

The purpose of the investigation was to replicate and extend a study by Jensen and Munro which found reaction time (RT) and movement time (MT) parameters to correlate negatively and moderately with Raven matrices performance. A sample of 20 ninth-grade girls was used. Relationships between RT and MT and Raven scores were found to be negative and moderate to high, thus replicating the Jensen and Munro study. In addition, moderate to strong negative correlations were found between RT and MT parameters and reading comprehension and performance on the California Test of Basic Skills. Weaker relationships were found for mathematics and English grades although the direction was consistently negative.     

Reaction time and accuracy in individuals with aphasia during auditory vigilance tasks

Research indicates that attentional deficits exist in aphasic individuals. However, relatively little is known about auditory vigilance performance in individuals with aphasia. The current study explores reaction time (RT) and accuracy in 10 aphasic participants and 10 nonbrain-damaged controls during linguistic and nonlinguistic auditory vigilance tasks. Findings indicate that the aphasic group was less accurate during both tasks than the control group, but was not slower in their accurate responses. Further examination of the data revealed variability in the aphasic participants' RT contributing to the lower accuracy scores.     

Reaction time to the second of two shortly spaced auditory signals both varying in intensity

Six subjects participated in a reaction time (RT) task in which the stimulus events consisted of two sinusoidal waves presented in close succession. The leading stimulus (S₁) had a duration of 25 msec while the binary reaction stimulus (S₂) was 250 msec. Presentation of the interstimulus interval (ISI) was irregular. S₁ as well as S₂ varied in intensity and were assigned randomly the values of 45, 68, 85 and 105 db (SPL). RT to S₂ was examined as a function of the intensity of both stimuli. Generally RT varied inversely with the intensity of S₁ and the downward gradient of RT with ISI became steepened at least for ISIs shorter than 200–250 msec. Concerning S₂, RT grew shorter as the intensity increased up to 85 db. Probably due to startle, RT tended to lengthen at S₂ = 105 db. When both S₁ and S₂ were 105 db the startle effect upon RT seemed most evident. Then the elevation in RT took place at especially those ISIs for which he fastest RTs might have been expected (about 200 msec). For the remaining intensities no interaction between S₁ and S₂ upon RT was found even for the shortest ISIs, implying that the effects of S₁ and S₂ intensities upon RT were independent.     

Short-term retention of tactile stimulation

In three experiments subjects were required to reproduce after varying delays the locus of a tactile stimulation delivered to the upper-side of the arm. During the retention periods subjects either performed a subsidiary, arithmetic task or rested. Recall, as measured by accuracy in reproducing the locus of stimulation, decreased as a function of retention interval, asymptoting after approximately 5 s. Performance was poorer in the subsidiary task condition than in the rest condition; however, the effect of the subsidiary task appeared to be more on subject recall strategies than on rehearsal capacity. No evidence of proactive interference effects was found, and a decay interpretation of forgetting of discrete tactile stimuli in the short-term memory distractor paradigm was favoured.     

Attention of preschool children: electrodermal activity during auditory stimulation

Electrodermal activity during passive and active listening tasks of 43 healthy preschool children (aged 4 yr., 8 mo. to 6 yr., 5 mo.) was studied. The procedure included the following phases: baseline recording (3 min.), a passive listening task, instructions, and an active listening task. An increase in mean amplitude of skin conductance response (SCR) was found during the active listening task over the level for the passive listening task over 10 trials. On the passive listening task from Trial 1 to Trial 10, habituation of mean SCR amplitude occurred. The younger children, moreover, exhibited significantly greater habituation than the older children. Habituation of mean SCR amplitude did not occur during the active listening task. No significant difference was found in mean SCR amplitude during the active listening task for the two age groups. The children seemed to pay more attention during the active listening task than during the passive listening task. The younger children, moreover, are believed to have shorter attention spans.     

Sequential predictability effects on initiation time and movement time for adults and children

First-grade children and adults performed a two-choice initiation-time/ movement-time task in which signals were (a) more likely to repeat than alternate, (b) more likely to alternate than repeat or (c) equally likely to alternate or repeat. Sequential predictability influenced initiation time but not movement time for adults and for children. These results do not support the suggestion (Wickens, 1974) that sequential predictability affects initiation time and movement time for children but only initiation time for adults. Adults and first graders did differ in their response to repeated events. Adults averaged faster initiation time for alternated than repeated responses and children averaged faster initiation time for repeated than alternated responses.