Reaction times and error rates for judging nominal identity of letter strings

Most theories of “same”-“different” judgments predict that “same” responses should be at least as slow as “different” responses. However, the contrary has often been found. To explain this, a two-processor model has been proposed. In this model, a fast processor and a slow processor operate simultaneously. “Same” responses are initiated by whichever processor first indicates that the stimuli are “same,” whereas “different” responses are initiated only by the slow processor. In the experiment reported here, Ss judged whether two successively presented letter strings were nominally “same” or “different.” It was expected that the fast processor would be incapable of making nominal identity judgments. Thus, both “same” and “different” responses would be initiated by the slow processor. Consequently, “same” responses should have been slower than “different” responses. However, this did not occur. This finding casts doubt upon, but does not disprove, the two-processor model.     

Reaction times and error rates for “same”-“different” judgments of multidimensional stimull

Each S indicated whether two successively presented rows of letters were “same” or “different.” Reaction times of the “different” response seemed to indicate that S examined the stimulus letters in a serial, self-terminating manner. However, the reaction times of the “same” response were not consistent with this model. Consequently, it was proposed that S employs simultaneously two distinct processes for comparing stimuli. One process would generate the “different” responses; the other process would generate the “same” responses. Most false “same” responses occurred when the two rows of letters differed minimally. Thus, the false “same” responses appear to result from a failure to detect the difference between the two stimuli. However, when S made a false “same” response, he was aware that he had done so. Therefore, it was suggested that only one of the two comparison processes failed to detect the stimulus difference.     

Facilitation of both “same” and “different” judgments of letter strings by familiarity of letter sequence

Three experiments employing simultaneous matching were performed to extend recent findings that three kinds of familiarity—familiarity of letter sequences, familiarity of display configuration, and familiarity of letter orientation—facilitate the matching of letter strings for “same” responses and sometimes for “different” responses. It was found that letter sequence familiarity facilitated “same” responses even when the letter strings were in an unfamiliar orientation or configuration and also facilitated “different” responses whenever the task required that a substantial portion of the display be processed before a response could be initiated. A three-stage model of the simultaneous letter-string matching task was developed. This model, which assumes that the same processes account for both “same” and “different” responses, was consistent with findings obtained when there were small differences between string pairs. Discrepant findings obtained when there were large differences between string pairs may have been produced by the premature initiation of responses.     

Learning on a response continuum: Comparison of a linear change and a functional learning model

Two reinforcement schedules were used to compare the predictive validity of a linear change model with a functional learning model. In one schedule, termed “convergent,” the linear change model predicts convergence to the optimum response, while in the other, termed “divergent,” this model predicts that a subject's response will not converge. The functional learning model predicts convergence in both cases. Another factor that was varied was presence or absence of random error or “noise” in the relationship between response and outcome. In the “noiseless” condition, in which no noise is added, a subject could discover the optimum response by chance, so that some subjects could appear to have converged fortuitously. In the “noisy” conditions such chance apparent convergence could not occur.The results did not unequivocally favor either model. While the linear change model's prediction of nonconvergence in the divergent conditions (particularly the “noisy” divergent condition) was not sustained, there was a clear difference in speed of convergence, counter to the prediction inferred from the functional learning model. Evidence that at least some subjects were utilizing a functional learning strategy was adduced from the fact that subjects were able to “map out” the relation between response and outcome quite accurately in a follow-up task. Almost all subjects in the “noisy” conditions had evidently “learned” a strong linear relation, with slope closely matching the veridical one.The data were consistent with a hybrid model assuming a “hierarchy of cognitive strategies” in which more complex strategies (e.g., functional learning) are utilized only when the simpler ones (e.g., a linear change strategy) fail to solve the problem.     

Short-term recognition memory for pitch: Effect of a priori probability on response times and error rates

A previous finding (Bindra, Williams, & Wise, 1965) that Ss respond “different” more quickly than “same” when comparing the pitch of two tones was confirmed. It was found that this effect could be enhanced by making same trials less frequent and that the effect could be reversed by making same trials more frequent. The experimental treatment also affected the error rates of the two responses. Error and latency results are discussed in terms of a model of R T based upon a sequential-sampling and decision procedure, and are shown to be compatible with such a model. A decision bias towards the response “different” must be taken into account when the model is applied. This bias appears to be influenced by the size of the interstimulus interval used.     

Speed and accuracy of same and different responses in perceptual matching

Models of the visual perceptual matching process are evaluated in two experiments in which the relative speeds of “same” and “different” responses were manipulated. In the first experiment, subjects were tested under two bias conditions: they were instructed to respond “same” only when sure or to respond “different” only when sure. Such bias is found to have a very large effect on the speed and accuracy of “same” and “different” responses, changing “same” responses from being faster than “different” responses (the usual result) in the sure “different” condition to being slower in the sure “same” condition. In the second experiment, the relative speed of “same” responses was slowed significantly by the addition of difficult “different” judgments. These results are used to argue against models that contain an identity matcher and against models that have separate components to account for errors and reaction time. We also point out that, although it is well known that the relative speeds of positive and negative responses are subject to bias manipulations, this fact has been ignored by many researchers in developing models in which the reaction time difference between positive and negative responses is used as a measure of a stage of processing.     

前额叶神经振荡活动反映了稳固的刺激冲突和反应冲突

为考察典型Flanker任务中练习对刺激冲突和反应冲突的影响,本研究采用练习范式记录被试完成2:1字母Flanker任务时的行为和脑电数据。行为结果发现,练习对这两类冲突无显著影响。神经震荡能量结果发现,前额叶theta能量随练习而显著减弱,这暗示刺激-反应之间的联结因练习而提升;前额叶alpha能量差异不随练习而变化,这可能反映了Flanker任务中稳定的刺激冲突和反应冲突加工机制。因此,本研究揭示了典型Flanker任务中刺激冲突和反应冲突的稳定特征。     

REDUCING AGGRESSIVE AND SELF-INJURIOUS BEHAVIOR OF INSTITUTIONALIZED RETARDED CHILDREN THROUGH REINFORCEMENT OF OTHER BEHAVIORS1

Aggressive and self-injurious behaviors of four retarded children were reduced by combining various techniques with the differential reinforcement of other behaviors (DRO). In one study, aggressive responses of a severely retarded child were reduced when DRO was combined with a 30-sec timeout. In a second study, various aggressive classroom behaviors were reduced when the child was told “no” for an inappropriate response but earned puzzle pieces for periods of time when inappropriate responses did not occur. Exchangeable tokens were given to a third subject for every 15 min in which aggressive responding did not occur, while each inappropriate response resulted in the loss of all tokens accrued. Responding was decreased to a level far below baseline. For a fourth child, self-injurious responses were followed by “no”, and intervals of time in which no self-injurious responding occurred earned candy. The rate of this behavior reduced significantly. In each case, the DRO procedure combined with the other techniques proved to be manageable for the teacher and successful in reducing the inappropriate behavior.     

Switching attention within and between categories: Evidence for intracategory inhibition

In a variation of the Posner and Snyder (1975b) paradigm, subjects made speeded “same” or “different” responses to pairs of digits or letters on the basis of name identity (Experiment 1) or physical identity (Experiment 2). Each target pair was preceded by an informative (letter or digit) or noninformative (plus-sign) warning signal. The letter or digit represented by an informative warning signal had a high probability of appearing in the subsequent target pair (expected condition). On trials in which the expected stimulus did not appear in the target pair, the target pair belonged with equal probability to either the same category (either letters or digits) as the expected stimulus or to the opposite category (unexpected-similar and unexpected-opposite conditions, respectively). The pattern of “benefits” and “costs” of attentional expectancy found by Posner and Snyder for “same” responses was replicated: Subjects were faster and more accurate in the expected condition than in the neutral (uninformative warning signal) condition, but slower and less accurate in the unexpected conditions. Present theoretical interest concerns “same” response times and accuracy for the two unexpected conditions. Under instructions emphasizing accuracy as well as speed (Experiments 1 and 2), performance was worse in the unexpected-similar condition than in the unexpected-opposite condition. Only when instructions deemphasized accuracy (Experiment 2) was performance better in the unexpected-similar condition than in the unexpected-opposite condition. The fact that subjects may have more difficulty switching attention within a category than between categories (at least when instructions emphasize accuracy as well as speed) contrasts sharply with current theoretical emphasis on intracategorical facilitation effects in the priming paradigm. The results are interpreted within the framework of a model of attention (Keele & Neill, 1978) in which the activation of associates to the focus of attention is actively and optionally suppressed so as to reduce present or potential interference with the focal information processing.     

You better stop! Binding “stop” tags to irrelevant stimulus features

We investigated whether the basic process of integrating stimuli (and their features) with simultaneously executed responses transfers to situations in which one does not respond to a stimulus. In three experiments, a stop-signal task was combined with a sequential priming paradigm to test whether irrelevant stimulus features become associated with a “stop” tag. Stopping a simple response during the prime trial delayed responding and facilitated stopping in the probe if the same irrelevant stimulus feature was repeated in the probe. These repetition priming effects were independent of the relation between the to-be-executed (or to-be-stopped) responses in the prime and probe, indicating that “stop” tags are global (“stop all responses!”) rather than being response-related (e.g., “stop left response!”).     

The role of response force on the persistence and structure of behavior during extinction

Behavior Momentum Theory has emerged as a prominent account of resistance to change in both basic and applied research. Although laboratory studies often define precise, repeatable responses, application research often deals with response classes that may vary widely along a number of dimensions. In general, Behavior Momentum Theory has not addressed how response dimensions impact resistance to change, providing an opportunity to expand the model in new directions. Four rats pressed a force transducer under a multiple variable interval (VI) 60‐s VI 60‐s schedule of reinforcement. In one component, responses satisfied the schedule only if the response force fell within a “low” force band requirement; responses in the other schedule were required to satisfy a “high” force band. Once responding stabilized, extinction was programmed for three sessions. Then, the procedures were replicated. The results showed that response force came under discriminative control, but force requirements had no impact on resistance to extinction. In a follow‐up condition, the schedule was changed to a multiple VI 30‐s VI 120‐s schedule and the low‐force band operated in both components. The results showed that behavior maintained by the VI 30‐s schedule was generally more resistant to extinction. A secondary analysis showed that force distributions created under baseline maintained during extinction. Overall, the results suggest that differential response force requirements prevailing in steady state do not affect the course of extinction.     

WITHIN‐SESSION TRANSITIONS IN CHOICE: A STRUCTURAL AND QUANTITATIVE ANALYSIS

The present study used within‐session transitions between two concurrent schedules to evaluate choice in transition. Eight female Long‐Evans rats were trained to respond under concurrent schedules of reinforcement during experimental sessions that lasted 22 hr. The generalized matching equation was used to model steady‐state behavior at the end of each session, while transitional behavior that emerged following the change in reinforcement schedules was modeled using a logistic equation. The generalized matching and logistic equations were appropriate models for behavior generated during single‐session transitions. A local analysis of behavior on the two response alternatives during acquisition was used to determine the source of preference as revealed in response ratios. The number of “low‐response” visits, those containing three to five responses, remained stable. Preference ratios largely reflected a sharp increase in the number of visits with long response bouts on the rich alternative and a decrease in the number of such visits to the leaner alternative.     

The effect of explicitly varying the proportion of “same” and “different” responses on sex differences in the Shepard and Metzler mental rotation task

The mental rotation of three-dimensional objects is consistently identified as the most salient cognitive sex difference in humans. The Shepard and Metzler task (1971) requires participants to rotate an object in their “mind's eye” and then compare the shape to a second object to identify if the two objects can be aligned in an identical orientation (warranting a “same” response) or represent mirror image shapes of one another (warranting a “different” response). The mental rotation task not only involves a rotational component but also nonrotational components such as comparison and decision making. Recent research has suggested that the sex difference in mental rotation resides in the nonrotational aspects of “different” decisions specifically. This experiment examined this proposal by varying the proportion of “different” decisions across conditions. Participants were ether exposed to the traditional format (50:50 same/different) or a bias towards (75:25) or away from (25:75) different responses. Contrary to previous research, the sex difference was found to reside in “same” responses that required a greater degree of rotation when assessing error rates in mental rotation. Sex differences in mental rotation error rates were particularly sensitive to the rotational aspect of same responses, not rotational aspects of different responses nor nonrotational aspects of both same and different responses. For reaction time, however, a sex difference emerged in the nonrotational aspects of the task. The bias described here affected these nonrotational aspects of the task, but not the rotational aspects, in line with prediction. A second study reran the experiment without making the bias explicit. Under this implicit bias, no sex differences were identified between conditions.     

The associated nontargets effect: Evidence of nontarget processing at and beyond the level of letter recognition

In four visual search tasks participants were asked to make a target response if either of two targets was present and to make a nontarget response if neither target was present. Some target-absent displays included only nontarget stimuli or features that never occurred in the same displays as targets, whereas other target-absent displays included nontarget stimuli or features that did sometimes occur with targets. Nontarget responses were reliably faster in the former case than in the latter. This “associated nontargets effect” indicates that nontargets are not simply classified as nontargets but in addition are discriminated from one another. Current visual search models may underestimate the degree to which nontargets are processed during search.     

Effects of stimulus features and instruction on response coding,selection, and inhibition: Evidence from repetition effects under task switching

The coding of stimuli and responses is crucial for human behaviour. Here, we focused primarily on the response codes (or response categories). As a method, we applied a combined dual-task and task-switch paradigm with a fixed task-to-hand mapping. Usually, negative effects (i.e., costs) are observed for response category repetitions under task switching. However, in several previous studies it has been proposed that such repetition effects do not occur, if the stimulus categories (e.g., “odd” if digits have to be classified according to their parity feature) are unequivocally mapped to specific responses. Our aim was to test this hypothesis. In the present experiments, we were able to distinguish between three different types of possible response codes. The results show that the participants generally code their responses according to abstract response features (left/right, or index/middle finger). Moreover, the spatial codes were preferred over the finger-type codes even if the instructions stressed the latter. This preference, though, seemed to result from a stimulus–response feature overlap, so that the spatial response categories were primed by the respective stimulus features. If there was no such overlap, the instructions determined which type of response code was involved in response selection and inhibition.     

Speed of emotional information processing and emotional intelligence

The present study aimed to investigate the relationship between the speed of emotional information processing and emotional intelligence (EI). To evaluate individual differences in the speed of emotional information processing, a recognition memory task consisted of two subtests similar in design but differing in the emotionality of the stimuli. The first subtest required judgment about whether an emotional facial expression in the test face was identical to one of the four emotional expressions of the same individual previously presented. The second subtest required deciding whether the test face with a neutral emotional expression was identical to one of the four neutral faces of different individuals previously presented. Mean response latencies were calculated for “Yes” and “No” responses. All latencies were correlated with other measures of processing speed such as discrimination time and time of figure recognition. However, the emotional expression recognition subtest was hypothesized to require the processing of emotional information in addition to that of facial identity. Latencies in this subtest were longer than those in the face recognition subtest. To obtain a measure of the additional processing that was called for by the emotionality of the stimuli, a subtraction method and regression analysis were employed. In both cases, measures calculated for “No” responses were related to ability EI, as assessed via a self‐report questionnaire. According to structural equation modeling, there was a moderately negative association between latent EI and the latency of “No” responses in the subtest with emotional stimuli. These relationships were not observed for “Yes” responses in the same subtest or for responses in the subtest with neutral face stimuli. Although the differences between “Yes” and “No” responses in their associations with EI require further investigation, the results suggest that, in general, individuals with higher EI are also more efficient in the processing of emotional information.     

Visual attention and coactivation of response decisions for features from different dimensions

The role of visual attention in task performance has been extensively debated. On the basis of the dimensional-action model, we hypothesized that a major role of attention is to transfer response decisions from targets on which it is focused to high-level centers dealing with response execution. This hypothesis predicts that response decisions for two targets will interact only when attention is focused on both targets, and only when the response to the targets is defined by different dimensions. Three experiments, using the redundancy-gain paradigm, tested and confirmed this prediction. Experiment 1 showed that coactivation of two cross-dimensional targets occurred only when the targets were positioned in the same location, not when they were in separate locations. Experiment 2 manipulated the focus of attention and showed that coactivation can occur even for targets positioned in different locations if they are both within the attentional focus. Experiment 3 showed that this attention-induced coactivation does not occur for targets from the same dimensional module. These results suggest that a major role of attention is postperceptual and involves gating of selected responses to executive functions.     

Impulsive Responses In Children with Conduct Disorder and Borderline Intellectual Functioning

The study is designed to investigate response inhibition in children with conduct disorder and borderline intellectual functioning. To this end, children are compared to a normal peer control group using the Alertness test. The test has two conditions. In one condition, children are instructed to push a response button after a visual “go” signal is presented on the screen. In a second condition the “go” signal is preceded by an auditory signal, telling the child that a target stimulus will occur soon. Compared to the control group, the group carrying the dual diagnosis made many preliminary responses (responses before the presentation of the “go” signal), especially in the condition with an auditory signal. This impulsive response style was controlled for attention deficit/hyperactivity disorder characteristics of the children.     

Perceptual hysteresis in the judgment of auditory pitch shift

Perceptual hysteresis can be defined as the enduring influence of the recent past on current perception. Here, hysteresis was investigated in a basic auditory task: pitch comparisons between successive tones. On each trial, listeners were presented with pairs of tones and asked to report the direction of subjective pitch shift, as either “up” or “down.” All tones were complexes known as Shepard tones (Shepard, 1964), which comprise several frequency components at octave multiples of a base frequency. The results showed that perceptual judgments were determined both by stimulus-related factors (the interval ratio between the base frequencies within a pair) and by recent context (the intervals in the two previous trials). When tones were presented in ordered sequences, for which the frequency interval between tones was varied in a progressive manner, strong hysteresis was found. In particular, ambiguous stimuli that led to equal probabilities of “up” and “down” responses within a randomized context were almost fully determined within an ordered context. Moreover, hysteresis did not act on the direction of the reported pitch shift, but rather on the perceptual representation of each tone. Thus, hysteresis could be observed within sequences in which listeners varied between “up” and “down” responses, enabling us to largely rule out confounds related to response bias. The strength of the perceptual hysteresis observed suggests that the ongoing context may have a substantial influence on fundamental aspects of auditory perception, such as how we perceive the changes in pitch between successive sounds.