Reaction Time Analysis of Two Types of Motor Preparation for Speech Articulation: Action as a Sequence of Chunks

Reaction time (RT) prior to speech articulation increased as a function of response complexity. The RT findings formed 2 patterns, each of which was a different Response Complexity × Paradigm (choice RT vs. simple RT) interaction. That result extends previous findings from manual button-pressing tasks (S. T. Klapp, 1995) to a different action modality. Two different types of response programming, INT and SEQ, are assumed in the interpretation. Whereas INT can be identified with response programming within a word, SEQ fits a different interpretation related to timing of onsets of speech units. A critical assumption is that a long response is represented as a sequence of chunks; that organization is subject to manipulation. New findings suggest some modifications of the previous theory.     

Change detection evokes a Simon-like effect

The present experiment studied choice response context effects on the programming of response sequences using behavioural and electrophysiological methods. Participants were asked to produce responses differing in sequence length (1-key vs. 3-key responses) with either their left or right hand in a choice reaction time (RT) task. The choice response context was manipulated by a blocked or mixed execution of 1-key and 3-key responses. A sequence length effect on RT was observed in the blocked but not in the mixed condition. The time course of the lateralized readiness potential indicates a motoric locus of the sequence length effect, suggesting that the response hand is activated before the entire motor program is established.     

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.     

On choosing between movement sequences: comments on Rose (1988)

One method of investigating human motor programming is to determine how the choice reaction time for a memorized response sequence depends on the composition of that sequence as well as the other sequence that may be required. Using this method, Rose (1988) found that the total number of responses in the two possible response sequences predicts the choice reaction time to initiate either one. On the basis of this result, Rose claimed that the hierarchical editor (HED) model of motor programming, developed by Rosenbaum, Inhoff, and Gordon (1984), may have to be reevaluated. In this commentary I argue that Rose's results are inconsistent with a precursor of the HED model, not with the HED model itself, that the HED model actually provides a better fit to Rose's data than her total-number-of-responses model, that in general, choice reaction time does not increase with the total number of possible responses, and that structural relations between alternative movement sequences are the main determinants of choice reaction time. Taken as a whole, the results suggest that possible responses are not held in completely readied form before being selected for execution. A further implication is that the storage capacity of the motor output buffer (the MOB) is extremely limited.     

Programmed control of aimed movements revisited the role of target visibility and symmetry

Reaction time prior to starting a 2-mm amplitude aimed movement was studied as a function to target size and experimental procedure. Consistent with a report by Klapp, choice reaction time increased as target size decreased when the visual signal that initiated the reaction time interval also indicated which of two targets was to be hit. This result implies response programming during the reaction time interval, with more programming time for slower movements to smaller targets. By contrast, in a simple reaction time procedure, there was no effect of target size on reaction time, suggesting that the response can be programmed in advance when the appropriate target is precued. This provided a control for speed-accuracy trade-off, supporting the programming interpretation of the choice reaction time result. In another condition in which both targets could be viewed while waiting for the auditory signal that initiated the reaction time interval and indicated which target to hit, choice reaction time was independent of target size provided that both possible targets on each trial were of the same size. The overall results suggest that response programs include both spatial and temporal information, and that parallel programming of different spatial goals is possible provided that the responses are of the same duration.     

Relation of repetition effect and response programming in a speeded choice task.

The present study tested the hypothesis that the repetition effect occurs during response programming. The choice reaction-time to initiate the second of two responses was examined when two consecutive responses were the same or different in their kinematics and force characteristics and repeated for two different stimuli. 12 subjects were required to react and produce the sequence of same or different force by squeezing a handle as quickly and accurately as possible after the first (auditory) and the second (visual) reaction signals. The response-stimulus interval was set at 500 msec. The choice reaction-time to initiate the second response was significantly shorter for the same-force condition than for the different-force and control conditions. This result indicates that the repetition effect originates in a speedup in response programming rather than response selection or perceptual identification. This finding was discussed in terms of bypassing a response-programming stage.     

Reaction time analysis of two types of motor preparation for speech articulation: action as a sequence of chunks

Reaction time (RT) prior to speech articulation increased as a function of response complexity. The RT findings formed 2 patterns, each of which was a different Response Complexity x Paradigm (choice RT vs. simple RT) interaction. That result extends previous findings from manual button-pressing tasks (S. T. Klapp, 1995) to a different action modality. Two different types of response programming, INT and SEQ, are assumed in the interpretation. Whereas INT can be identified with response programming within a word, SEQ fits a different interpretation related to timing of onsets of speech units. A critical assumption is that a long response is represented as a sequence of chunks; that organization is subject to manipulation. New findings suggest some modifications of the previous theory.     

Motor Programming as a Function of Constraints on Movement Initiation

Three experiments are reported that test the hypothesis that under certain conditions programming time is a function of the directional accuracy demand of a response, directional accuracy being quantified by the minimal angle subtended at the point of movement initiation by the circular targets within the response. Subjects in three simple reaction time experiments were required to tap a single target or a series of circular targets as rapidly as possible with a hand-held stylus. Experiments 1 and 3 showed that the subtended angle (SA) of a response can have a more powerful effect on programming time, as indexed by reaction time and premotor time, than the number of movement parts in the response. The results of Experiment 2 revealed that the locus of the directional accuracy effect was SA and not target size or movement distance. In all three experiments, response SA was a better predictor of programming time than was number of movement parts, target size, movement distance, movement time, and average movement velocity. The findings support the notion that constraints placed upon movement initiation by the directional accuracy demand of the task can play an important role in determining the length of the programming process.     

An additive factors analysis of the effect(s) of location cues associated with auditory stimuli on stages of information processing

The additive factors method (AFM) was used as a tool for assessing the locus (or loci) of the detrimental effect of auditory location cues in the chain of (visual) information processing. In the first experiment the location variable was factorially combined with response specificity, which is assumed to affect the response adjustment stage. A second experiment was performed in which movement amplitude, assumed to affect the response programming stage, was manipulated in addition to the location variable and a different variety of response specificity. Finally, the location variable was combined with relative S-R frequency, which is also assumed to affect the response programming stage, in a third experiment. The results of these experiments showed additive effects of the location variable with motor variables. The remaining two experiments were designed to assess the effects of location cues on response selection. In these experiments the location variable was combined with the number of response alternatives. Response speed decreased with an increase in the number of response alternatives. However, the effects of the location variable and number of response alternatives were additive. According to the additive factor logic, then, the results of experiments 1, 2 and 3 seem to indicate that the locus of interference of the location cues is not in the later response stages of the reaction process. The results of the last two experiments were interpreted to suggest that the effects of location cues and the number of response alternatives affect either different processes within the response selection stage or affect different process stages. It was concluded that the latter alternative explains most of the data currently available and that the stimulus identification stage is the most likely candidate for the locus of the location effect.     

Motor programming as a function of constraints on movement initiation

Three experiments are reported that test the hypothesis that under certain conditions programming time is a function of the directional accuracy demand of a response, directional accuracy being quantified by the minimal angle subtended at the point of movement initiation by the circular targets within the response. Subjects in three simple reaction time experiments were required to tap a single target or a series of circular targets as rapidly as possible with a hand-held stylus. Experiments 1 and 3 showed that the subtended angle (SA) of a response can have a more powerful effect on programming time, as indexed by reaction time and premotor time, than the number of movement parts in the response. The results of Experiment 2 revealed that the locus of the directional accuracy effect was SA and not target size or movement distance. In all three experiments, response SA was a better predictor of programming time than was number of movement parts, target size, movement distance, movement time, and average movement velocity. The findings support the notion that constraints placed upon movement initiation by the directional accuracy demand of the task can play an important role in determining the length of the programming process.     

Spatial compatibility interference effects: a double dissociation between two measures

ABSTRACT

In spatial compatibility tasks, when the spatial location of a stimulus is irrelevant it nevertheless interferes when a response is required in a different spatial location. For example, response with a left key-press is slowed when the stimulus is presented to the right as compared to the left side of a computer screen. However, in some conditions this interference effect is not detected in reaction time (RT) measures. It is typically assumed that the lack of effect means the irrelevant spatial code was not analysed or that the information rapidly decayed before response. However, we show that even in conditions where there appears to be no spatial interference when measuring RTs, effects can nevertheless be detected after response when recording facial electromyography responses. This dissociation between two measures highlights the importance of diverging methods to investigate visuomotor processes as conclusions based on only one measure can be misleading.     

The Effect of Feedback Schedule Manipulation on Speech Priming Patterns and Reaction Time

Speech priming tasks are frequently used to delineate stages in the speech process such as lexical retrieval and motor programming. These tasks, often measured in reaction time (RT), require fast and accurate responses, reflecting maximized participant performance, to result in robust priming effects. Encouraging speed and accuracy in responding can take many forms, including verbal instructions and feedback, and often involves visually displayed RT feedback. However, it is uncertain how manipulation of the schedule of this RT feedback influences speech RT speed and, ultimately, the priming effect. This experiment examined the effect of visually presented RT feedback schedules on priming patterns in 20 older healthy adults. Results suggested that feedback schedule manipulation had a differential effect on reaction time, depending on the interstimulus interval between the prime and the target, but no effect on response priming patterns.     

Scheduling and programming of rapid finger sequences: tests and elaborations of the hierarchical editor model

Is a response sequence executed only after the sequence has been fully programmed, as discrete processing models predict, or does execution begin before programming has been completed, as continuous processing models predict? To address this issue, we tested a discrete processing model of human motor performance, the hierarchical editor model of Rosenbaum, Inhoff, and Gordon (1984). This model was developed to account for data from experiments in which people perform one of two possible finger sequences, depending on the identity of a choice signal. The model assumes a hierarchically organized motor program that is first "edited" to resolve any uncertainties and is then "executed" to produce the desired responses. Three experiments reported here show that, contrary to the model's predictions and some well-known motor programming results (Sternberg, Monsell, Knoll, & Wright, 1978), the reaction time to begin a response sequence actually decreases with the length of the sequence under some choice conditions. We account for these results with a model that allows execution to begin while editing is still in progress. A key assumption in the model is that subjects schedule execution so that means and variances of interresponse times are minimized.     

Attentional localization prior to simple and directed manual responses

The relationship between attention and the programming of motor responses was investigated, using a paradigm in which the onsets of targets for movements were preceded by peripheral attentional cues. Simple (button release) and reaching manual responses were compared under conditions in which the subjects either made saccades toward the target location or refrained from making eye movements. The timing of the movement onset was used as the dependent measure for both simple and reaching manual responses. Eye movement latencies were also measured. A follow-up experiment measured the effect of the same peripheral cuing procedure on purely visual processes, using signal detection measures of visual sensitivity and response bias. The results of the first experiment showed that reaction time (RT) increased with the distance between the cued and the target locations. Stronger distance effects were observed when goal-directed responses were required, which suggests enhanced attentional localization of target positions under these conditions. The requirement to generate an eye movement response was found to delay simple manual RTs. However, mean reaching RTs were unaffected by the eye movement condition. Distance gradients on eye movement latencies were relatively shallow, as compared with those on goal-directed manual responses. The second experiment showed that the peripheral cue had only a very small effect on visual detection sensitivity in the absence of directed motor responses. It is concluded that cue-target distance effects with peripheral cues are modulated by the motor-programming requirements of the task. The effect of the peripheral cue on eye movement latencies was qualitatively different from that observed on manual RTs, indicating the existence of separate neural representations underlying both response types. At the same time, the interactions between response modalities are consistent with a supramodal representation of attentional space, within which different motor programs may interact.     

Attentional localization prior to simpleand directed manual responses

The relationship between attention and the programming of motor responses was investigated, using a paradigm in which the onsets of targets for movements were preceded by peripheral attentional cues. Simple (button release) and reaching manual responses were compared under conditions in which the subjects either made saccades toward the target location or refrained from making eye movements. The timing of the movement onset was used as the dependent measure for both simple and reaching manual responses. Eye movement latencies were also measured. A follow-up experiment measured the effect of the same peripheral cuing procedure on purely visual processes, using signal detection mea-sures of visual sensitivity and response bias. The results of the first experiment showed that reaction time (RT) increased with the distance between the cued and the target locations. Stronger distance ef-fects were observed when goal-directed responses were required, which suggests enhanced attentional localization of target positions under these conditions. The requirement to generate an eye movement response was found to delay simple manual RTs. However, mean reaching RTs were unaffected by the eye movement condition. Distance gradients on eye movement latencies were relatively shallow, as compared with those on goal-directed manual responses. The second experiment showed that the peripheral cue had only a very small effect on visual detection sensitivity in the absence of directed motor responses. It is concluded that cue-target distance effects with peripheral cues are modulated by the motor-programming requirements of the task. The effect of the peripheral cue on eye movement latencies was qualitatively different from that observed on manual RTs, indicating the existence of separate neural representations underlying both response types. At the same time, the interactions be-tween response modalities are consistent with a supramodal representation of attentional space, within which different motor programs may interact.     

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.     

Attentional Orienting in Two-dimensional Space

This paper examines how the covert orienting of spatial attention affects motor responses to visual stimuli. Premotor theories, as well as hemi-field inhibition accounts of visual attention predict an increase in response times when a target stimulus appears in the opposite direction to a spatial cue. Some models also suggest that this meridional effect should be increased across oblique meridians. Two types of cue (central and peripheral) were used to orient attention towards locations prior to the onset of visual targets. Simple manual (press button) and saccadic responses were measured. No meridional effects were found with peripheral cues, whereas central cueing produced meridional effects across all meridians. Cueing effects did not vary significantly with two-dimensional axis for either manual or saccadic responses. Increases in response time with cue-target distance were found for both response and cue types. For saccades, distance gradients were shallower moving distally rather than proximally from the cued position. However, simple manual responses did not show this asymmetry. Orienting to central cues also modulated the amplitude of saccades. The results are consistent with an effect of attentional cues in oculomotor centres as well as the existence of actiondependent attentional representations. However, it is proposed that, rather than reflecting oculomotor programming, meridional effects arise from a directional organization within spatio-cognitive representations.     

注意力资源限制与双任务的相互干扰机制

采用心理不应期研究范式, 两个反应时实验检测了注意力资源分配的特征以及双任务的相互干扰机制。每次实验中, 要求被试快速、相继对高低音辨别任务(T1)和Stroop任务(T2)作出选择性反应, T1和T2间采用6种不同的时间间隔(SOA), 以系统考察不同SOA条件下两个任务的反应时走势。结果发现：(1) 在重叠的双任务情境中, T1的中枢加工导致在T2上出现显著的PRP效应, T2的中枢反应选择对T1的反应选择和反应执行加工同样产生显著的影响。SOA以及T2的难度与复杂度实质性地影响了T1的反应选择和反应执行加工。(2) 当两个任务同时需要进行中枢反应选择加工时, 一个任务占用更多的注意资源将导致另一任务获得较少的注意资源, 注意资源量的多寡直接决定了该任务的加工效率。(3) 两个任务的加工相互影响、相互制约, 这种制约机制不仅仅存在于中枢反应选择阶段, 在反应执行阶段仍然存在。     

Influence of Destabilization on the Temporal Characteristics of “Volitional” Stepping

Previous work suggests that there may be fundamental differences between compensatory stepping responses evoked by postural perturbation and visually cued “volitional” stepping (e.g., gait initiation). In contrast to visual cueing, postural destabilization evokes an array of sensory inputs that are intrinsically linked to the mobilization of rapid compensatory responses. The hypothesis examined in this study was that this fundamental difference would lead to distinct changes in the temporal characteristics of the stepping response. Six healthy young adults were instructed to step quickly in response to either visual cueing or anterioposterior platform motion. Both forward and backward stepping responses were characterized, using measures of vertical ground reaction force. A stereotypical temporal patterning of the stepping response occurred in both stimulus conditions and both directions of stepping, and anticipatory postural adjustments were evident in all trials. However, postural destabilization led to a more rapid initiation and execution of the temporal pattern, in comparison with visually cued responses. The most pronounced effect was seen in the duration of the response, which was reduced by a factor of two, with approximately proportional foreshortening of both the preparatory and swing phases. The results suggest that sensory information conveying a state of instability has a distinct influence on the characteristics of a subsequent stepping reaction. The persistence of the anticipatory postural adjustments suggests that the failure to see this element of the response in previous studies may reflect fundamental differences between volitional and unplanned compensatory stepping.     

Programming time as a function of number of movement parts and changes in movement direction

The question of whether changes seen in simple reaction time (SRT) as a function of response complexity (i.e., number of movement parts) should be considered as differences in the time needed to centrally program a motor response was addressed. Using a large-scale tapping response, 14 subjects contacted from one to five targets positioned in a straight line, while a second group of 14 subjects executed 90 degrees changes in direction in striking the targets. Results revealed that mean SRT and mean premotor time increased linearly as the number of movement parts increased, regardless of whether changes in movement direction had to be programmed, with the greatest increase occurring between one-, and two-part responses. Increases in motor time were not sufficient to account for the sizeable SRT effect. These findings support the position of increased central programming time for more complex responses, and also help establish some of the boundaries of the complexity effect.