Effects of frontalis tension level on discrimination task accuracy and reaction time

The frontalis muscle is a focal point of many relaxation training programmes, so the effects of varying frontalis tension levels on concurrent task performance need consideration when recommending in situ muscle relaxation. Two experiments are reported; performance on a discrimination task was examined across high, moderate, and low induced frontalis tension. When length of exposure to the task stimuli was unlimited, accuracy of discrimination was affected by tension; when exposure was limited, reaction time was affected. In both experiments the high frontalis tension resulted in better performance than the other levels. Implications for the practice of in situ relaxation are considered.     

Effects of speed and accuracy strategy on choice step execution in response to the flanker interference task

The purpose of this study is to examine the effects of a speed or accuracy strategy on response interference control during choice step execution. Eighteen healthy young participants were instructed to execute forward stepping on the side indicated by a central arrow (←, left vs. →, right) under task instructions that either emphasized speed or accuracy of response in the neutral condition. In the flanker condition, they were additionally required to ignore the 2 flanking arrows on each side (→→→→→, congruent or →→←→→, incongruent). Errors in the direction of the initial weight transfer (APA errors) and the step execution times were measured from the vertical force data. APA error was increased in response to the flanker task and step execution time was shortened with a speed strategy compared to an accuracy strategy. Furthermore, in response to the visual interference of the flanker task, speed instructions in particular increased APA errors more than other instructions. It may be important to manipulate the level of the speed-accuracy trade-off to improve efficiency and safety. Further research is needed to explore the effects of advancing age and disability on choice step reaction in a speed or accuracy strategy.     

Effects of domain-specific exercise load on speed and accuracy of a domain-specific perceptual-cognitive task

In the context of perceptual-cognitive expertise it is important to know whether physiological loads influence perceptual-cognitive performance. This study examined whether a handball specific physical exercise load influenced participants’ speed and accuracy in a flicker task. At rest and during a specific interval exercise of 86.5–90% HR_max, 35 participants (experts: n = 8, advanced: n = 13, novices, n = 14) performed a handball specific flicker task with two types of patterns (structured and unstructured). For reaction time, results revealed moderate effect sizes for group, with experts reacting faster than advanced and advanced reacting faster than novices, and for structure, with structured videos being performed faster than unstructured ones. A significant interaction for structure × group was also found, with experts and advanced players faster for structured videos, and novices faster for unstructured videos. For accuracy, significant main effects were found for structure with structured videos solved more accurately. A significant interaction for structure × group was revealed, with experts and advanced more accurate for structured scenes and novices more accurate for unstructured scenes. A significant interaction was also found for condition × structure; at rest, unstructured and structured scenes were performed with the same accuracy while under physical exercise, structured scenes were solved more accurately. No other interactions were found. These results were somewhat surprising given previous work in this area, although the impact of a specific physical exercise on a specific perceptual-cognitive task may be different from those tested generally.     

Effects of speed and accuracy instructions on performance in a visual search task by children with good or poor attention

Children rated by teachers as having good or poor attention ability carried out a visual search task in which they were required to find a series of targets in a complex display. Different groups were told to concentrate on either speed or accuracy. Previous studies using this task have consistently shown that children rated as having poor attention make more errors (false alarms to non‐targets in the display), but do not differ in the time to make a correct response; this result was replicated. Though the instructions produced wide differences in speed and error rates in the expected directions, these differences were similar in both attention groups and the differences in error rates between the two groups remained unchanged. It is suggested that these findings are not compatible with the view that children with poor attention make errors primarily due to fast impulsive responding, nor with an explanation in terms of slower processing of the input by such children. An alternative explanation of the high error rates in such children is offered in terms of weak executive function resulting in poor ability to inhibit false alarms to non‐targets.     

The speed and accuracy of perceptual decisions in a random-tone pitch task

Research in perceptual decision making is dominated by paradigms that tap the visual system, such as the random-dot motion (RDM) paradigm. In this study, we investigated whether the behavioral signature of perceptual decisions in the auditory domain is similar to those observed in the visual domain. We developed an auditory version of the RDM task, in which tones correspond to dots and pitch corresponds to motion (the random-tone pitch task, RTP). In this task, participants have to decide quickly whether the pitch of a “sound cloud” of tones is moving up or down. Stimulus strength and speed–accuracy trade-off were manipulated. To describe the relationship between stimulus strength and performance, we fitted the proportional-rate diffusion model to the data. The results showed a close coupling between stimulus strength and the speed and accuracy of perceptual decisions in both tasks. Additionally, we fitted the full drift diffusion model (DDM) to the data and showed that three of the four participants had similar speed–accuracy trade-offs in both tasks. However, for the RTP task, drift rates were larger and nondecision times slower, suggesting that some DDM parameters might be dependent on stimulus modality (drift rate and nondecision time), whereas others might not be (decision bound). The results illustrate that the RTP task is suitable for investigating the dynamics of auditory perceptual choices. Future studies using the task might help to investigate modality-specific effects on decision making at both the behavioral and neuronal levels.     

Modeling the effects of payoff on response bias in a perceptual discrimination task: bound-change, drift-rate-change, or two-stage-processing hypothesis

Three hypotheses--the bound-change hypothesis, drift-rate-change hypothesis, and two-stage-processing hypothesis--are proposed to account for data from a perceptual discrimination task in which three different response deadlines were involved and three different payoffs were presented prior to each individual trial. The aim of the present research was to show (1) how the three different hypotheses incorporate response biases into a sequential sampling decision process, (2) how payoffs and deadlines affect choice probabilities, and (3) the hypotheses' predictions of response times and choice probabilities. The two-stage-processing hypothesis gave the best account, especially for the choice probabilities, whereas the drift-rate-change hypothesis had problems predicting choice probabilities as a function of deadlines.     

A diffusion model account of response time and accuracy in a brightness discrimination task: fitting real data and failing to fit fake but plausible data

A brightness discrimination experiment was performed to examine how subjects decide whether a patch of pixels is “bright” or “dark,” and stimulus duration, brightness, and speed versus accuracy instructions were manipulated. The diffusion model (Ratcliff, 1978) was fit to the data, and it accounted for all the dependent variables: mean correct and error response times, the shapes of response time distributions for correct and error responses, and accuracy values. Speed-accuracy manipulations affected only boundary separation (response criteria settings) in the model. Drift rate (the rate of accumulation of evidence) in the diffusion model, which represents stimulus quality, increased as a function of stimulus duration and stimulus brightness but asymptoted as stimulus duration increased from 100 to 150 msec. To address the argument that the diffusion model can fit any pattern of data, simulated patterns of plausible data are presented that the model cannot fit.     

Inspection time and response strategies in a choice response task

The effects of varying stimulus duration on two response measures, percentage correct (p_c) and mean reaction time (RT) were investigated in a lights-keys RT task similar to an inspection time (IT) task. One of either N = 2, 4 or 8 lights came on as the stimulus, followed after a range of stimulus exposure durations (D) by all 8, as a backward mask. It was found that p_c was an ogival function of D for all three levels of choice, and that the standard deviations of the best-fitting normal ogives were equal. It is argued that the standard deviation can be taken as a measure of the neural noise, or error-inducing variability introduced by processing the stimulus, and so this result indicated that noise in the choice reaction task is independent of N. The effect of D on RT was as predicted by an optional accumulator model for 7 Ss with RT decreasing as D increased, while another 2 Ss appeared to have adopted a temporal deadline criterion giving RTs independent of D and equal error and correct RTs. The same two response styles were found in a re-analysis of RT data from an IT study. The p_c vs D curves were comparable for both response styles. The accumulator model commonly assumed to underly IT tasks thus does not describe the behaviour of all Ss. Such individual differences in strategic approach to the IT task should be investigated further, since assuming that all Ss use one approach may hide or confound relationships between IT and other measures of individual difference, such as intelligence. Recommendations for better IT measurement techniques are given.     

Exposure duration: Effects on eyewitness accuracy and confidence

The current study examined the relationship between the length of exposure to a face in an eyewitness setting and identification accuracy and confidence. A sample of 164 young (ages 17–25) and older (ages 59–81) adults viewed a simulated crime in which they saw the culprit's face for a short (12 s) or long (45 s) duration. They were then tested with a target absent (a line‐up not containing the culprit) or target present line‐up. Identification accuracy rates for both young and older participants were significantly higher under the long exposure condition. In the short exposure condition, witnesses who had made a correct identification of the target were more confident than incorrect witnesses. In the long exposure condition the confidence ratings of accurate and inaccurate witnesses did not differ. Discussion focuses on the extent to which extended exposure may inflate confidence judgments and variables that may moderate the relationship between exposure duration and face recognition accuracy.     

The effects of speed and accuracy strategies in an information-reduction task

Developmental changes in the ability to make relational judgments of sound intensity were examined with 3-, 4-, and 5-year-old children. The hypothesis that correct judgments of “louder” precede correct judgments of “softer” was supported. The results were discussed with reference to the development of the understanding of logical relations as proposed by Piaget. The role of magnitude of perceptual information in the development of relational judgments also was discussed.     

Effects of amount of information on judgment accuracy and confidence

When a person evaluates his or her confidence in a judgment, what is the effect of receiving more judgment-relevant information? We report three studies that show when judges receive more information, their confidence increases more than their accuracy, producing substantial confidence–accuracy discrepancies. Our results suggest that judges do not adjust for the cognitive limitations that reduce their ability to use additional information effectively. We place these findings in a more general framework of understanding the cues to confidence that judges use and how those cues relate to accuracy and calibration.     

Effect of task, selection set, and dispersion of attention on visual identification time

Schioldborg, P., Paus, E. & Myhre, G. Effect of task, selection set, and dispersion of attention on visual identification time. Scand. J. Psychol., 1973, 14, 195–198. Letters and digits were presented in rows of one, two, or three, and the time required for identifying their position, colour, class, or names recorded for three subjects. The identification tasks were performed under three different conditions of preparatory set, making use of position, colour, and class as selecting attributes. (1) Under each selection set, only the identification of letters and digits as such required more time with increasing number of items, indicating limiting conditions for a "constancy" model of attention. (2) For all identification tasks, selection procured by class yielded longer identification time than selection by position or colour, suggesting different levels of complexity in information processing. (3) Identification of class under a position set, or position under a class set, required less time than the corresponding combinations with colour in place of position, suggesting that analysis of form and position relate basically to the same processes.     

Developmental differences in a coincident timing task under speed and time constraints

The present study examines the effects of speed constraints (target velocity) and time constraints (target duration) on performance on a coincident timing task by 5-, 7- and 9-year-old children and adults. The results showed that the young children significantly improved their performance (per cent of hits) and response accuracy CE, |CE| when given longer time to perform the task. The adults were just as successful for both durations. All subjects showed better performance (per cent of hits) with slower targets, however, for the children this effect was only noticeable with targets of long duration. Target duration also revealed development changes in response control and execution, with the younger children producing different response patterns for IRT, MT and IP measures. The developmental differences at this task are discussed in terms of the control mechanisms involved and the use of strategies in responding.     

Trading accuracy for speed: gender differences on a Stroop task under mild performance anxiety.

A standard Stroop task was used to examine the effect of performance anxiety on 58 male and 69 female undergraduates. Subjects were approached either by two casually dressed experimenters who did not stress speed or accuracy or by 4 or 5 formally dressed experimenters who stressed quick and accurate performance. Subjects were told the test would assess their "mental acuity"; their responses were visibly tape-recorded. Reaction times did not show differential response by anxiety condition; men and women showed different RTs only in the low-anxiety condition, with women performing significantly more slowly. There were no significant differences for the high-anxiety condition. Analysis of errors showed women were more accurate than men. Men traded accuracy for speed and may have been under equal performance stress in both situations. When performance was not stressed, women were slower and more accurate than men. When performance was stressed, women increased their speed to match that of men while maintaining their greater accuracy.     

Manipulating response set in a choice reaction task: evidence for anatomical coding in response selection

Accurate motor performance requires a process of response selection that chooses the correct response out of a set of possible ones. Most theories of response selection assume that this selection process operates on spatial codes, which define the location of stimuli and responses in environmental coordinates, with little or no role for the anatomical codes of the effectors involved. In this study, I systematically manipulated the anatomical identities of the response fingers in a four-choice reaction task, while keeping the stimulus and response locations constant. Results showed that homologous fingers on different hands modulated the reaction time profiles and error patterns in a mirror-symmetrical way. This finding indicates that anatomical factors may play a more substantial role in response selection than often assumed.     

Choice and response time processes in the identification and categorization of unidimensional stimuli

Lacouture and Marley (1991, 1995, 2001) have successfully modeled the probabilities of correct responses and the mean correct response times (RTs) in unidimensional absolute identification tasks for various stimulus ranges and stimulus/response set sizes, for individual and group data. These fits include those to a set of phenomena often referred to as end-anchor effects. A revised model, with the independent accumulator decision process replaced by a leaky competing accumulator decision process, fits the probabilities of correct responses and the full distributions of RTs in unidimensional absolute identification. The revised model is also applied successfully to a particular class of unidimensional categorization tasks. We discuss possible extensions for handling sequential effects in unidimensional absolute identification, and other extensions of the given class of categorization tasks that are of potential empirical and theoretical importance as a supplement to the study of multidimensional absolute identification tasks.