双任务情境下心理旋转的并行加工机制

采用心理不应期研究范式,三个反应时实验检测了心理旋转任务和其他认知操作任务能否并行加工的问题。在每个实验中要求被试快速、系列地完成对高低音的辨别任务(T1)和不同旋转角度的正反像辨别任务(T2),T1和T2呈现的时间间隔运用变化的SOA。结果发现：(1)T1的反应选择对T2的反应选择产生了很大的影响,在T2上PRP效应显著。心理旋转的操作成绩随着SOA的缩短而降低。(2)在T1上同样存在随着SOA缩短,反应时增加,正确率下降的趋势。T2的反应选择对T1的反应选择同样产生了显著的影响。(3)T2的反应选择对T1的中枢加工产生了相应的影响,表明当T1的反应选择占据中枢瓶颈时,心理旋转任务和其他认知操作任务在中枢瓶颈中并行得到了有效的加工     

Generalizations and extensions of the precue-utilization effect in rapid reactions.

The method of brief PSIs (precue-to-stimulus intervals) was used in three RT (reaction-time) experiments to explore the generality of the precue-utilization effect in rapid reactions, and to examine two extensions. This effect, which shows the self-contained performance in the choice reaction of the processing operations that culminate in response selection, generalized to a quantitative discrimination and to unequal stimulus-response (SR) frequencies. In the first extension, the reduction in wrong-alternative errors at relatively long PSIs indicated that these errors occur in conjunction with commitment to response actualization. In the second extension, the duration of discrimination-selection was found to be no longer for the less frequent of two SR alternatives. Taken together, these findings indicate that the effect of relative SR frequency, on incidence of errors as well as length of RT, fell on response-actualization processing. This is in accord with a number of previous findings and consonant with effects of RT variables on movement parameters but contrary to cumulative speed-accuracy models.     

The effect of memory load on reaction time in character classification

In order to investigate the effect of memory load on reaction time (RT), choice RT trials were embedded in a binary character classification task using the varied set procedure. Twelve Ss performed in experimental blocks, as well as in control blocks consisting of character classification trials only. In experimental blocks, every trial began as a classification trial with the presentation of a new positive set. On a random half of these trials, however, a choice RT stimulus was presented instead of a probe letter and S simply made the indicated response. Results indicated that memory load had no effect on the choice RT trials. Embedding choice RT trials in the classification task affected the intercept (but not the slope) of the function relating classification RT to memory load. This result implies that the increase in latency usually obtained in classification experiments is entirely due to an increase in the duration of the memory searching stage of processing.     

Verification of Donders' subtraction method

In an experiment on 6 young adults advance (precued) information of the correct choice response was utilized completely: (a) For precue-to-stimulus intervals (PSIs) clearly shorter than the difference between mean choice and simple reaction time (RT), median response latency (L) measured from precue onset was invariant; (b) For clearly longer PSIs, median RT was very near the value for simple RT. This precue-utilization effect would be expected if response actualization had been delayed until the response had been selected and if the requirement for discrimination and selection had no adverse effect on readiness to respond. Donders' (1868/1969) hypothesis in his initial application of the subtraction method, that choice and simple reactions are identical except for the serial insertion of discrimination and selection operations in the former, is thereby strongly supported. If this formulation is accepted, models that hold that response processing can overlap other processing stages may be considered valid only for response selection, not response actualization.     

Precueing response factors in choice reaction time: a word of caution

This note discusses the assumption researchers make when movement attributes are precued in a choice reaction time (RT) paradigm-i.e., that the precue only reduces the number of response alternatives, so that changes in RT reflect the programming time for the unprecued attributes. However, it is argued that since the precue reduces the number of stimulus alternatives, changes in RT reflect changes in both stimulus processing and response programming. Therefore, the interpretation made by Klapp (1977), using the precue paradigm, that response selection and response timing are not independent sequential stages in the programming sequence, is not necessarily correct.     

Precueing Response Factors in Choice Reaction Time

This note discusses the assumption researchers make when movement attributes are precued in a choice reaction time (RT) paradigm—i.e., that the precue only reduces the number of response alternatives, so that changes in RT reflect the programming time for the unprecued attributes. However, it is argued that since the precue reduces the number of stimulus alternatives, changes in RT reflect changes in both stimulus processing and response programming. Therefore, the interpretation made by Klapp (1977), using the precue paradigm, that response selection and response timing are not independent sequential stages in the programming sequence, is not necessarily correct.     

Selective effects of barbiturate and amphetamine on information processing and response execution

In a 3 × 2 × 2 factoral experiment, 12 subjects carried out a choice reaction task with reaction time (RT) and movement time (MT) as response measures.Independent variables were drug treatment (amphetamine, barbiturate, placebo), visual stimulus degradation and S-R compatibility. Visual stimulus degradation and S-R compatibility showed additive effect on the RT, but did not affect the MT. This confirms that stimulus encoding, response selection and response execution represent independent processing stages. The two drugs had selective effects on the RT and the MT. Barbiturate (as compared to placebo) had no effect on the MT, but it lengthened the RT, and this effect was additive with the effects of S-R compatibility but showed an interaction with the effects of stimulus degradation. Amphetamine (as compared to placebo) shortened the MT, but there was no significant main effect of amphetamine on the RT although the interaction with the effect of S— compatibility was significant. These results suggest that barbiturate affects stimulus encoding whereas amphetamine affects response-related processes..     

Stage analysis of the reaction process using brain-evoked potentials and reaction time

Summary Motor processes partly determine reaction time (RT) in both choice reaction time and in binary classification tasks. These latter tasks are popular in cognitive psychology because the experimenter believes that he has kept the motor component simple and constant and therefore can attribute changes in RT to perceptual or cognitive processes. In this paper we used the P3 component of the event-related potential (ERP) as a time marker indicating the duration of perceptual and cognitive processes. The latency of this component is believed to reflect stimulus evaluation time independent of response selection and organization time.Two types of tasks were used: a choice-reaction time task and a binary classification task. Signal similarity and S-R compatibility additively affected RT, but only signal similarity affected P3 latency. The number of items in the positive set and response type affected both P3 latency and RT. Relative response frequency changed the bias in the cognitive evaluation of the stimulus, reflected in the latency of the P3 component, and affected RT only if the subjects preset their motor system (indexed by the late CNV). A model was presented which proposes that motor processes may partially overlap with the perceptual and cognitive evaluation of the stimulus. Both ERPs and RT are necessary tools in the study of the relative timing of these processes.     

On the relation between stimulus intensity and processing time: Piéron’s law and choice reaction time

Piéron (1914, 1920, 1952) demonstrated that simple reaction time (SRT) decays as a hyperbolic function of luminance in detection tasks. However, whether such a relationship holds equally for choice reaction time (CRT) has been questioned (Luce, 1986; Nissen, 1977), at least when the task is not brightness discrimination. In two SRT and three CRT experiments, we investigated the function that relates reaction time (RT) to stimulus intensity for five levels of luminance covering the entire mesopic range. The psychophysical experiments consisted of simple detection, two-alternative forced choice (2 AFC) with spatial uncertainty, 2 AFC with semantic categorization, and 2 AFC with orientation discrimination. The results of the experiments showed that mean RT increases with task complexity. However, the exponents of the functions relating RT to stimulus intensity were found to be similar in the different experiments. This finding indicates that Piéron’s law holds for CRT as well as for SRT. It describes RT as a power function of stimulus intensity, with similar exponents, regardless of the complexity of the task.     

The "short-long" reaction time effect in duration programming

The programming processes concerned with response duration were studied in a precueing and in a priming reaction time (RT) paradigm. Participants had to produce a motor response of a specified duration as soon as possible after a response signal (RS) preceded by a warning signal (WS), which could deliver information on 2 response parameters (duration and effector). In Experiment I (precueing; N = 12), 3 effectors (the right hand, the left hand, or the knees) and 3 durations (.7, 2.5, or 5.5 s) were contrasted. Two responses differing in their biomechanical features were required in 2 blocks of trials: Subjects had to accurately time the duration of either a sustained button press or an interval between 2 brief presses. The RT patterns revealed a short-long effect: Shorter RTs were produced before the short duration than before the longer, provided that the duration was not precued. This short-long effect occurred whatever type of response and effector were involved. Two conclusions were reached. First, response duration was included in the motor program elaborated before execution, whatever the biomechanical features of the response; and, second, the program for the short duration was activated on all trials and was used as a basis for programming longer durations when needed. These conclusions were tested in Experiment 2 (priming; N = 12), in which a small proportion of invalid trials concerning duration was provided. Thus, the duration required by the RS differed from that primed by the WS. Two durations (.7 or 2.5 s) and 2 effectors (the index or the middle finger) were involved. In the invalid trials, the responses of short and long durations did not yield any RT differences, thus confirming the particular status of the short duration. This suggests that deprogramming operations (which lengthen the RT) are needed after a RS to produce short response durations but not after a RS to produce long response durations in the invalid trials.     

Stimulus and response prediction in choice reaction time: Free vs. forced reactions

Verbal predictions were combined in a 1:many mapping in order to analyze the contribution of response preparation to both stimulus and response prediction effects in choice reaction time (RT). Using a three-stimulus, two-response task in which two of the stimuli were mapped 1:1 to separate responses (forced-choice) and the third stimulus was mapped to both responses (free-choice), response frequencies and latencies were compared in two experiments. The results indicated that (1) free-choice response selections were not influenced by forced-choice stimulus predictions; (2) free-choice RTs were reduced only when the free-choice stimulus was correctly predicted; (3) free-choice responses were generally consistent with the response predicted, but RT did not depend on response prediction; (4) on forced-choice trials, the RT difference between correct and incorrect predictions was similar for stimulus and response predictions; and (5) under no-prediction conditions, no difference was found between free and forced RTs. A stimulus anticipation component was the only apparent contribution to the stimulus prediction effect, while the response prediction data suggest some prior response selection with no associated decrease in latency     

Beyond drug effects and dependent variables: the use of the Poisson-Erlang model to assess the effects of D-amphetamine on information processing

Several studies have shown that d-amphetamine (DAMP) speeds mean reaction time (RT). However, the use of mean RT may obscure important aspects of the drug response. Therefore we applied the Poisson-Erlang (PE) stochastic model of choice reaction time proposed by Pieters (1985) to the RT distribution. This model proposes that the RT distribution is generated by two states: Processing (P) and Distraction (D). RT represents the sum of the time spent in each of these states. P is the time taken to complete a set of cognitive operations which are required to give a correct response. D represents the time taken by all other activities. RTs were collected using a task (SERS) in which stimulus and response complexity each had two levels, easy and hard. Subjects were tested pre- and postdrug. Drug conditions were: placebo, 10 mg d-amphetamine (DAMP), 4 mg of the dopamine agonist, pimozide, and a combination of DAMP and pimozide (COMBO). Parameters of the model were derived using methods described by Pieters. Four measures were analyzed: Processing Time (PT); Mean Time per distraction (XTD); Distraction Rate (DR); and Total Distraction Time per trial (TDT). Mean RT is also presented. Analyses of the effects of task conditions on the parameters of the model were made using the predrug sessions. Mean RT was increased by both stimulus and response complexities as was PT. TDT was increased by the task conditions. The PE measures did not change over days. DAMP speeded mean RT. However, this effect did not interact with the task factors. DAMP speeded processing and reduced distraction. Processing was speeded only in the hard response condition, distraction time was reduced only in the easy response condition. The results indicate that the PE model can be successfully applied to fast RT tasks. More importantly, the parameters of the model revealed important pharmacological effects that were not apparent in mean RT. DAMP speeds cognitive operations related to motor preparation and reduces the effects of distraction. Consistent with past studies there are no indications that DAMP interacted with stimulus processing. The distraction effect appears to be mediated by an increase in the rate of distraction and a decrease in the average time of these distractions.     

The specification of digit and duration during motor programming: a new method of precueing

This experiment manipulated digit uncertainty, duration uncertainty, and response duration (dit or dah) in a choice reaction time key press task. A new method of precueing was developed that effectively "precued" the digit and/or the duration of the key press task without confounding the number of stimulus response alternatives with the levels of uncertainty of digit and duration. When the duration of the response was certain, there were no RT differences between dit and dah responses, however, when duration was uncertain, RT to dah responses were longer than dit. In addition, level of duration uncertainty and digit uncertainty produced an overadditive interaction upon RT. These results are discussed in terms of generalized motor programs and a feature construction hypothesis. In addition, these results support the view that precueing of movement dimensions can be accomplished without confounding the number of stimulus response alternatives and the uncertainties of movement dimensions.     

Sequential effects of catch-trials on choice reaction time

The aim of the study was to examine whether or not choice reaction time (RT) depends on catch-trial frequency. The results show a significant increase of mean RT as the catch-trial frequency increases from zero to 0.77. A similar effect has been shown previously in simple RT experiments. The interpretation of these effects on simple RT supposes the existence of an inverse relationship between catch-trial frequency and anticipated response frequency. This cannot be extended to a choice RT task since the subject must wait for the stimulus to arrive before deciding which is the appropriate response. The interpretation of the present results proposes preparatory adjustments prior to the arrival of the stimulus. Sequential effects found suggest that (1) the tendency to prepare for a stimulus at a trial was stronger when a stimulus was presented at the preceding trial than after a catch-trial, and (2) the frequency effects of catch-trials can be explained completely in terms of sequential effects.     

The relationship between reaction time and intensity in discrete auditory tasks

The effect of signal intensity upon reaction time (RT) was studied in three auditory RT tasks in which the signal was a tone of high or low frequency. Experiment I showed the well-known negative gradient with intensity of simple RT when the subject was instructed to ignore the frequency and give the same response to both tones. But when the subject had to discriminate the frequency in a choice RT task, the RT/intensity relationship appeared to be U-shaped. Experiment II showed that when the subject was required to make a response to one signal but withhold it for the other, a task which requires discrimination of the frequency of the tone but removes the necessity to choose between overt responses, no increase in RT at high intensities was obtained. The results indicate that it is the response choice stage rather than the stimulus encoding stage which is retarded at higher energy levels. Experiment I also demonstrated that visual and auditory leading signals have similar facilitating effects without affecting the RT/intensity relationships.     

An additive factor analysis of the effect of depression on the reaction time of old patients

Depressed participants display longer reaction times (RTs) than control participants. The present study was aimed at deciphering which stages of processing are affected by depression in old adults. Sixteen old depressed patients and 16 old healthy volunteers performed a two-choice visual RT task. Signal intensity, stimulus-response mapping and foreperiod duration were manipulated so as to affect the stages of stimulus preprocessing, response selection and motor adjustment, respectively. Reaction time data suggest that depression spares the stage of stimulus preprocessing but affects the stage of motor adjustment. An analysis of the error rate leaves open the possibility that depression alters the stage of response selection.     

Concurrent deployment of visual attention and response selection bottleneck in a dual-task: Electrophysiological and behavioural evidence

Visual attention and response selection are limited in capacity. Here, we investigated whether visual attention requires the same bottleneck mechanism as response selection in a dual-task of the psychological refractory period (PRP) paradigm. The dual-task consisted of an auditory two-choice discrimination Task 1 and a conjunction search Task 2, which were presented at variable temporal intervals (stimulus onset asynchrony, SOA). In conjunction search, visual attention is required to select items and to bind their features resulting in a serial search process around the items in the search display (i.e., set size). We measured the reaction time of the visual search task (RT2) and the N2pc, an event-related potential (ERP), which reflects lateralized visual attention processes. If the response selection processes in Task 1 influence the visual attention processes in Task 2, N2pc latency and amplitude would be delayed and attenuated at short SOA compared to long SOA. The results, however, showed that latency and amplitude were independent of SOA, indicating that visual attention was concurrently deployed to response selection. Moreover, the RT2 analysis revealed an underadditive interaction of SOA and set size. We concluded that visual attention does not require the same bottleneck mechanism as response selection in dual-tasks.     

Locus of the intensity effect in simple reaction time tasks

Evidence is still inconclusive regarding the locus of the stimulus intensity effect on information processing in reaction tasks. Miller, Ulrich, and Rinkenauer (1999) addressed this question by assessing the intensity effect on stimulus- and response-locked lateralized readiness potentials (LRPs) as indices of the sensory and motor parts of reaction time (RT). In the case of visual stimuli, they observed that application of brighter stimuli resulted in a shortening of RT and stimulus-locked LRP (S-LRP), but not of response-locked LRP (R-LRP). The results for auditory stimuli, however, were unclear. In spite of a clear RT reduction due to increased loudness, neither S-LRP nor R-LRP onset was affected. A reason for this failure might have been a relatively small range of intensity variation and the type of task. To check for this possibility, we performed three experiments in which broader ranges of stimulus intensities and simple, rather than choice, response tasks were used. Although the intensity effect on the R-LRP was negligible, S-LRP followed RT changes, irrespective of stimulus modality. These findings support the conclusion that stimulus intensity exerts its effect before the start of motoric processes. Finally, S-LRP and R-LRP findings are discussed within a broader information-processing perspective to check the validity of the claim that S-LRP and R-LRP can, indeed, be considered as pure estimates of the duration of sensory and motor processes.     

Modulation of motor area activity during observation of unnatural body movements

We investigated the processes underlying stimulus-response compatibility by using a lateralized auditory stimulus in a simple and choice reaction time (RT) paradigm. Participants were asked to make either a left or right key lift in response to either a control (80 dB) or startling (124 dB) stimulus presented to either the left ear, right ear, or both ears. In the simple RT paradigm, we did not find a compatibility effect for either control or startle trials but did find a right-ear advantage which we attribute to anatomical asymmetry of auditory pathways. In the choice RT paradigm, we found compatibility effects for both startle and control trials as well a high incidence of error for contralateral stimulus-response mapping. We attribute these results to automatic activation of the ipsilateral response, which must then be inhibited prior to initiation of the correct response. The presence of compatibility effects for startle trials also suggest that similar pathways are being used to initiate movements in a choice RT situation, as opposed to involuntary triggering that is thought to occur in a simple RT situation.     

Effects of auditory stimulus intensity on response force in simple, go/no-go, and choice RT tasks

In four experiments, increasing the intensities of both relevant and irrelevant auditory stimuli was found to increase response force (RF) in simple, go/no-go, and choice reaction time (RT) tasks. These results raise problems for models that localize the effects of auditory intensity on purely perceptual processes, indicating instead that intensity also affects motor output processes under many circumstances. In Experiment 1, simple RT, go/no-go, and choice RT tasks were compared, using the same stimuli for all tasks. Auditory stimulus intensity affected both RT and RF, and these effects were not modulated by task. In Experiments 2-4, an irrelevant auditory accessory stimulus accompanied a relevant visual stimulus, and the go/no-go and choice tasks were used. The intensity of the irrelevant auditory accessory stimulus was found to affect RT and RF, although the sizes of these effects depended somewhat on the temporal predictability of the accessory stimulus.