Individual differences in children's performance during an emotional Stroop task: a behavioral and electrophysiological study

Two studies using the emotional Stroop with 11-year-old children were completed. In Study 1, children were assigned to either the "interference group" or the "facilitation group" based on their performance on the task. The interference group was slower to respond to emotion words (positive and negative) versus control words. The facilitation group was faster to respond to the emotion words. The groups were then compared on a set of cognitive, emotional, and social measures collected at ages 4, 7, and 11. The interference group showed greater signs of emotional and social, but not cognitive, maladjustment across time. Study 2 replicated the findings of Study 1. In addition, event-related potentials (ERPs) were collected in Study 2. The ERP data replicated earlier traditional Stroop studies. In addition, positive and negative words showed differences in processing across components. In particular, negative words appeared to tax attentional and processing resources more than positive words.     

The Stroop congruency effect is more observable under a speed strategy than an accuracy strategy

Naming the ink color of an incongruent color word (e.g., RED printed in green) usually takes longer than naming the ink color of a color bar. However, when the ink matches the word (e.g., RED printed in red), naming tends to be faster. These phenomena are known as the STroop interference effect and the Stroop congruency effect, respectively. Although the interference effect has been robust and reliable across studies, the congruency effect tends to be elusive. It was hypothesized that this variation in outcomes might be related to subjects' response strategy. The experiment conducted to test this hypothesis induced either a speed or an accuracy strategy in two separate groups of subjects. Significant interference effects were found for both groups and the magnitudes did not differ. At the same time, the congruency effect was observed in the speed group but not in the accuracy group. These results suggest that researchers who wish to observe and study the Stroop congruency and interference effects should place special emphasis on speed. Implications of the study for a model of the Stroop effect are also discussed.     

The effects of age and task context on Stroop task performance

In this study, we investigated the impact of age and task context on Stroop task performance, using error scores, response latencies, and process dissociation estimates (e.g., Lindsay & Jacoby, 1994). Across three experiments, the findings showed that although older adults were able to evaluate Stroop task demands and modify their representations of task context in response to this knowledge, they were less able to maintain and update these representations on a trial-by-trial basis in tasks with high stimulus uncertainty or ambiguity. Moreover, although there was no age-related decline in the ability to modulate print color information, older adults were consistently less able to control the activation of conflicting word information. Together, these findings suggest that whereas age differences in the Stroop task may be magnified under conditions that promote transient failures to maintain task context, the primary source of these differences seems to be a more enduring decline in the efficiency of processes that are responsible for suppressing the activation of irrelevant lexical information.     

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.     

Emotional Stroop task: effect of word arousal and subject anxiety on emotional interference

Inconsistent findings regarding the emotional Stroop effect in healthy subjects may be explained by confounding effects of stimulus valence and arousal, as well as individual differences in anxiety. We examined reaction time data in a healthy sample using the emotional Stroop task while carefully matching arousal level of positive and negative words. Independent of valence, emotional relative to neutral words elicited emotional interference, indicating that arousal determines emotional interference. Independent of valence, emotional words were better re-called and recognized than neutral words. Individual differences in state anxiety were associated with emotional interference, that is, emotional interference was enhanced in subjects with high state anxiety. There was no influence of trait anxiety. These findings indicate that word arousal produces emotional interference independent of valence. State anxiety exacerbates interference of emotional words by further biasing attention towards emotionally salient stimuli. Thomas Dresler and Katja Mériau have contributed equally.     

State anxiety, performance accuracy, and work pace in a simulated pharmacy dispensing task

This study examined the effects of scores on state anxiety on overall accuracy of performance and speed of working in a simulated pharmacy dispensing task. 75 undergraduates worked in a simulated pharmacy environment, designed by Schell and Grasha in 1998, to fill 42 mock orders for simulated pharmacy items. Participants' accuracy and work pace in the simulation, presimulation stress, and postsimulation perceived workload and state anxiety were measured. Analysis indicated that state anxiety and overall accuracy were strongly related. State anxiety appears to be one of the best predictors of errors in the simulated pharmacy dispensing task found so far, while the lack of relationship between work pace and accuracy was confirmed. Work pace predicted accuracy, indirectly, but only after statistically removing the effects of anxiety, task frustration, significant-other stress, and grade point average.     

Adults' versus children's performance on the Stroop task: Interference and facilitation

Stroop tasks (Stroop, 1935) present stimuli having two dimensions, and participants respond to one dimension whilst ignoring the other. The two dimensions are made congruent, incongruent or neutral with respect to one another. Many claim that ‘Stroop interference’ is higher in children than in adults. However, taking interference as the difference between the incongruent condition and the neutral condition, with interference within the congruent condition itself termed the ‘incongruity effect’ then surprisingly few studies directly address this issue. Also, there is recent debate as to whether the ‘facilitation effect’ (the contrast between the congruent and neutral conditions) is just the opposite of interference. The present investigation (N = 31) concerned a direct comparison between children and adults. Although the incongruity effect reduced with age, interference did not. However, facilitation was far higher in children than in adults. The groups' opposite facilitation/interference asymmetry was used to examine the recent claim that these derive from inadvertent word‐reading and suppression of semantic activation, respectively; rather than solely from the latter.     

Sex differences in performance on a combined manual and decision task.

This report describes results of an experimental study of the differences in response time between 10 male and 10 female undergraduate operators performing a combined manual and decision task. Analysis indicated that the performance times of women on such tasks were shorter than those of the men as expected.     

Individual but not fragile: Individual differences in task control predict Stroop facilitation

The Stroop effect is composed of interference and facilitation effects. The facilitation is less stable and thus many times is referred to as a “fragile effect”. Here we suggest the facilitation effect is highly vulnerable to individual differences in control over the task conflict (between relevant color naming and irrelevant word reading in the Stroop task). We replicated previous findings of a significant correlation between stop-signal reaction time (SSRT) and Stroop interference, and also found a significant correlation between SSRT and the Stroop facilitation effect—participants with low inhibitory control (i.e., long SSRT) had no facilitation effect or even a reversed one. These results shed new light on the “fragile” facilitation effect and highlight the necessity of awareness of task conflict, especially in the Stroop task.     

Effects of Stroop task duration on subsequent cognitive and physical performance

The strength model of self-control purports to explain why brief cognitive response inhibition tasks impair subsequent isometric handgrip endurance. According to the model, ego depleting tasks requiring self-control resources impair performance on subsequent tasks that also require self-control resources. However, several lines of evidence challenge this model, including evidence of improved exercise performance following longer cognitive tasks. Our study investigated the effects of cognitive task duration on (1) subsequent physical endurance performance, (2) concurrent cognitive task performance, and (3) subsequent novel cognitive task performance. Adopting an experimental design, with Stroop task type (incongruent, congruent) and duration (5, 10, 20 min) as between-participant factors, participants (N = 180) completed a color word Stroop task, an isometric handgrip to exhaustion task, and a novel 5-min incongruent number word Stroop task. In the handgrip task, endurance performance was worse following incongruent word Stroop than congruent word Stroop for 10-min tasks but not 5-min and 20-min tasks. In the word Stroop task, accuracy was lower and speed was slower following incongruent word Stroop than congruent word Stroop. Importantly, reaction times improved with longer task durations. In the novel number Stroop task, accuracy was higher following incongruent word Stroop than congruent word Stroop. In conclusion, the finding that the ego depletion effect was moderated by cognitive task duration is better explained by the expected value of control model than the strength model.     

Sex differences in performance and hemispheric organization for a nonverbal auditory task.

Musically experienced and inexperienced men and women discriminated among fundamental-frequency contours presented either binaurally (i.e., same contour to both ears) or dichotically (i.e., different contours to each ear). On two separate occasions, males made significantly fewer errors than did females in the binaural condition, but not in the dichotic condition. Subjects with prior musical experience were superior to musically naive subjects in both conditions. The dichotic pitch task produced a left-ear advantage, which was unrelated to gender or musical experience. The results suggest that the male advantage on the binaural task reflects a sex difference in the coordination of the two hemispheres during conjoint processing of the same stimuli rather than a difference in the direction or degree of hemispheric specialization for these stimuli.     

Expertise differences in a video decision-making task: Speed influences on performance

Video clips of different speeds were used in a simulation of decision-making in Australian football to test the effects on decision accuracy and decision time. Elite and sub-elite and novice Australian footballers watched videos in six speeds (0.75, 1.0, 1.25, 1.5, 1.75 and 2.0 times normal speed). Participants responded by using a mouse-click to indicate where they would pass the ball for that particular video clip. The elite and sub-elite groups also rated each clip for how ‘game-like’ the decision-making felt. The elite group was significantly more accurate than the sub-elite and novice groups, and the sub-elite group was more accurate than the novice group. Within-speed analysis showed the elite group excelled at the faster video speeds. The use of speeded video delineated clear expertise differences between the groups at the 1.5 speed. Elite and sub-elite players identified the 1.25 and 1.5 speeds as most ‘game-like’ for decision-making. These results show that athletes perceive moderately speeded video as more game-like. Speeded video is further speculated to have allowed elite athletes to perform more automatically, with a faster processing efficacy, a key characteristic of elite performance. This study suggests the use of speeded video as a potential new research paradigm to explore expertise and a viable method for future training interventions for decision-making.     

MMPI short forms with adolescents: gender differences in accuracy

The influence of gender on accuracy for eight short forms of the Minnesota Multiphasic Personality Inventory (MMPI) was investigated using a sample of adolescents. MMPI responses from 318 male and 248 female psychiatric patients, aged 12 to 17, were scored for the standard MMPI, Mini-Mult (using two methods; Kincannon, 1968), Midi-Mult (Dean, 1972), two Maxi-Mults (McLachlan, 1974; Spera & Robertson, 1974), Hugo Short Form (Hugo, 1972), Faschingbauer Abbreviated MMPI (FAM; Faschingbauer, 1974), and MMPI-168 (Overall & Gomez-Mont, 1974). Discrepancy values were obtained for all short-form T-scores by subtracting each short-form T-score from its corresponding standard form T-score. These discrepancy values were analyzed using Gender x Short Form repeated measures multivariate analyses of variance (MANOVAs). Because the number of scales varied among the short forms, two separate analyses were performed, one containing all short forms but only the 11 scales that appeared on all short forms and the other containing all scales but only the three short forms that contained all scales. McLachlan's (1974) Maxi-Mult was excluded from the analysis because of its nearly identical statistical properties to Spera and Robertson's (1974) Maxi-Mult. The interaction was significant on most scales in both analyses. Simple-effects breakdowns of the interactions revealed that the accuracy of each short form differed according to gender on several scales, following no consistent pattern. The Midi-Mult and Maxi-Mult are guardedly recommended as the short forms with the lowest number of scales showing a gender difference; however, the reader is cautioned that this difference is still present in more than one third of the scales. Further research on short-form development is advocated.     

Hypnotic susceptibility and verbal automaticity: automatic and strategic processing differences in the Stroop color-naming task.

The original hypothesis of Dixon, Brunet, and Laurence (1990) that highly hypnotizable (HH) subjects process words more automatically than do low hypnotizable (LH) subjects was retested in a paradigm that separated strategic from automatic processes in the Stroop color-naming task. The words red and blue preceded a color patch that was red or blue. Subjects were told that the word predicted the opposite color 75% of the time. Automatic and strategic processes were assessed by varying the interstimulus interval (ISI) between the word and the color patch. Both HH and LH subjects showed significant strategic effects (faster incongruent-trial, color-naming reaction times than congruent-trial reaction times at ISIs over 400 ms), but only HH subjects showed significant automaticity (significantly faster congruent-trial reaction times than incongruent-trial reaction times at 16.7 ms, the lowest ISI).     

Effects of anxiety on inferential reasoning task performance

Three experiments were conducted in which high anxiety and low anxiety subjects were required to construct inferences. In Experiment 1 there was no anxiety-related performance deficit when inferring a necessary anaphoric relation, a process argued to be automatic. Experiments 2 and 3 involved the verification of unnecessary inferences, a process argued to involve the utilization of the working memory system. In both Experiments 2 and 3 there was an anxiety-related performance deficit. The results are consistent with a working memory-oriented account of anxiety-related performance effects, as deficits were restricted to capacity-demanding tasks.     

Temporal constraints of the word blindness posthypnotic suggestion on Stroop task performance

The present work investigated possible temporal constraints on the posthypnotic word blindness suggestion effect. In a completely within-subjects and counterbalanced design 19 highly suggestible individuals performed the Stroop task both with and without a posthypnotic suggestion that they would be unable to read the word dimension of the Stroop stimulus, both when response-stimulus interval (RSI) was short (500 ms) or equivalent to previous studies (3500 ms). The suggestion reduced Stroop interference in the short RSI condition (54 vs. 6 ms) but not in the long RSI condition (52 vs. 56 ms), and did not affect Stroop facilitation. Our results suggest that response to the suggestion involves reactive top-down control processes that persist only if levels of activation can be maintained. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Effects of alternating set for speed or accuracy on response time,accuracy and confidence in a unidimensional discrimination task

Three approaches to a theoretical analysis of confidence judgments are considered: one linking confidence to the number of sensory observations, one based on a distinction between ‘state’ and ‘process’ factors, and a ‘balance of evidence’ hypothesis developed from an accumulator model of discrimination. An experiment is described in which observers were asked to decide which of two parallel lines was the longer, and to rate their confidence in each judgment. Each observer's set for speed or accuracy was manipulated over successive blocks of trials, and effects on response time, accuracy, and confidence were examined. Under an accuracy set, observers produced a higher percentage of correct responses, had longer response times, and made more confident judgments than under a set for speed. Within both speed and accuracy blocks, however, confidence ratings were inversely related to response time. The data on response accuracy, time, and confidence indicate certain deficiencies in either of the first two approaches, but were well accounted for by the third.     

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.