Strategic control in word reading: evidence from speeded responding in the tempo-naming task

To investigate strategic control over response initiation in word reading, the authors introduce the tempo-naming task. Relative to baseline performance in the standard-naming task, participants were induced to respond with faster latencies, shorter durations, and lower levels of accuracy by instructing them to time response initiation with an experimentally controlled tempo. The tempo response cue attenuated stimulus effects, and as faster tempos reduced latencies, the number of spelling-sound errors remained constant, whereas the number of word, nonword, and articulatory errors increased. To explain these results, the authors propose input gain as a mechanism of control over processing speed. The experimenters sketch how input gain could account for the current results as well as for the results from stimulus-blocking experiments testing the route emphasis and time criterion hypotheses of strategic control.     

Strategic influences on recollection in the exclusion task: Electrophysiological evidence

One assumption underlying the use of the exclusion task as part of the process dissociation procedure is that studied items are successfully excluded only when they are recollected. The present study employed event-related potentials (ERPs) to demonstrate that successful exclusion does not necessarily require recollection. In two experiments, the study tasks for to-be-excluded items were identical, but the tasks employed withtarget items differed, giving better memory for these items in Experiment 1 than in Experiment 2. Successfully excluded items elicited the ERP signature for recollection—theleft parietal old/new effect—in Experiment 2 only. These findings indicate that the subjects adopted different retrieval strategies in the two experiments. It is suggested that they made more use of source information about to-be-excluded items in the second experiment than in the first.     

Top-down task sets for combined features: Behavioral and electrophysiological evidence for two stages in attentional object selection

We studied whether visual search for targets defined by a combination of features from different dimensions is guided by separately represented target features or by an integrated representation of the target objects. In Experiment 1, participants searched for target singleton bars that were defined by a specific combination of color (red or blue) and size (small or large). The target arrays were preceded by cue arrays that contained a spatially uninformative color/size singleton. Behavioral spatial-cueing effects indicative of attentional capture were triggered only by cues that matched both target-defining features, but not by partially target-matching cues, suggesting that attention was guided by integrated object representations. However, the presence of reliable N2pc components for partially matching cues demonstrated that these cues did capture attention, in line with independent feature-based guidance of attention. This dissociation between the electrophysiological and behavioral markers of attentional capture was confirmed in Experiment 2, in which targets were defined by a color/size disjunction. Our results suggest that the attentional selection of targets that are defined by a combination of features is a two-stage process: Attention is initially captured by all target-matching features, but is then rapidly withdrawn from nontarget objects that share some but not all features with the current target.     

False-belief understanding in 2.5-year-olds: evidence from two novel verbal spontaneous-response tasks

Recent research indicates that toddlers and infants succeed at various non-verbal spontaneous-response false-belief tasks; here we asked whether toddlers would also succeed at verbal spontaneous-response false-belief tasks that imposed significant linguistic demands. We tested 2.5-year-olds using two novel tasks: a preferential-looking task in which children listened to a false-belief story while looking at a picture book (with matching and non-matching pictures), and a violation-of-expectation task in which children watched an adult 'Subject' answer (correctly or incorrectly) a standard false-belief question. Positive results were obtained with both tasks, despite their linguistic demands. These results (1) support the distinction between spontaneous- and elicited-response tasks by showing that toddlers succeed at verbal false-belief tasks that do not require them to answer direct questions about agents' false beliefs, (2) reinforce claims of robust continuity in early false-belief understanding as assessed by spontaneous-response tasks, and (3) provide researchers with new experimental tasks for exploring early false-belief understanding in neurotypical and autistic populations.     

Processing two tasks with varying task order: central stage duration influences central processing order

In a recent study, Sigman and Dehaene (2006, PLoS Biology, 4, 1227–1238) reported that perceptual processing duration influences processing order of two tasks in the psychological refractory period paradigm (PRP). The present study examines whether the duration of central processes also influences processing order. For this purpose, we employed letter tasks with different central processing durations and varied task order in the PRP. In one part of the experiment, a tone discrimination task was combined with a similar time-consuming letter discrimination task. In the other part, the tone task was combined with a more time-consuming letter task, which required a mental rotation of the letter thereby prolonging central processing. If the duration of central processes influences processing order, participants should perform the tone task first more often when it is presented with the more time-consuming mental rotation task, than when it is presented with the similar time-consuming letter task. The results clearly confirm this prediction and thus show that not only perceptual processing duration but also central processing duration affects processing order in a dual-task situation. We suggest that the reported effect mirrors a tendency of participants to minimize total reaction time to both tasks by reducing slack time.     

Asymmetric interference between domains: evidence from the stimulus order effect in complex span tasks

The stimulus order effect refers to the finding that recall in complex span tasks is better when span lists begin with a longer processing task and end with a shorter task than when these processing tasks are presented in the reverse order. This study independently manipulated processing time and processing difficulty between Long-final and Short-final lists. The processing task required participants to solve arithmetic problems with either verbal (Experiment 1) or visuospatial (Experiment 2) materials. The memory items used in the storage task were either digits (verbal material) or dots-in-matrices (visuospatial materials). Storage of both verbal and visuospatial materials was sensitive to the change in processing difficulty, but not processing time. Furthermore, this study provides further evidence for the asymmetry of domain interference in working memory. The similarities and differences between verbal and visuospatial storage in working memory are discussed.     

Perceptions of similarity between striving tasks and the generality of task preferences

Ninth graders rated their degree of liking for each of 12 striving tasks and, on another occasion, rated their perceptions of the similarity between each pair of tasks. Analyses of variance revealed strong PersonX Task interactions, suggesting the possibility of individual differences in task preference generality. A derived measure of task preference generality-specificity related significantly to an overall measure of perceived task similarity—generalizers saw the tasks as being more similar than did specifiers. Investigation of individual differences in degree of cross-situational generality was suggested as a way to integrate trait and situational theories of behavior.Data collection and initial data analyses for this study were conducted under the auspices of the Institute for Juvenile Research, Chicago, Illinois. Gratitude is expressed for the cooperation of the staffs and students at St. Michaels and Immaculata high schools, Chicago; for useful discussions of theoretical issues with Mark Oberlander; and for much assistance with data analysis provided by Arthur Kendall.     

The link between speech perception and production is phonological and abstract: evidence from the shadowing task

This study reports a shadowing experiment, in which one has to repeat a speech stimulus as fast as possible. We tested claims about a direct link between perception and production based on speech gestures, and obtained two types of counterevidence. First, shadowing is not slowed down by a gestural mismatch between stimulus and response. Second, phonetic detail is more likely to be imitated in a shadowing task if it is phonologically relevant. This is consistent with the idea that speech perception and speech production are only loosely coupled, on an abstract phonological level.     

Irrelevant differences in the "same"--"different" task

This article examines the effects of irrelevant information on the multidimensional "same"--"different" task. Subjects were instructed to compare two geometric figures with respect to certain attributes but to ignore other attributes in making the "same"--"different" decision. The irrelevant attributes were chosen in such a way that they could not easily be ignored to see how the existence of irrelevant differences would affect the comparison process. As expected, the overall latencies were longer than is usually found in tasks with no irrelevant differences. However, the nature of the comparison process appeared unchanged. The usual finding of a "fast-same" phenomenon persisted even when irrelevant information was present. The similarity of the results in this task to results in the "same"--"different" task with no irrelevant features supports the idea that the same comparison mechanism is used whether or not irrelevant differences are present in the stimulus pairs. The results suggest a more general-purpose comparison mechanism than is usually included in models of this task. Two-process models of visual comparisons are thus ruled out entirely. A modified version of Krueger's noisy-operator theory does appear consistent with the results.     

There are at least two kinds of probability matching: evidence from a secondary task

Probability matching is a suboptimal behavior that often plagues human decision-making in simple repeated choice tasks. Despite decades of research, recent studies cannot find agreement on what choice strategies lead to probability matching. We propose a solution, showing that two distinct local choice strategies—which make different demands on executive resources—both result in probability-matching behavior on a global level. By placing participants in a simple binary prediction task under dual- versus single-task conditions, we find that individuals with compromised executive resources are driven away from a one-trial-back strategy (utilized by participants with intact executive resources) and towards a strategy that integrates a longer window of past outcomes into the current prediction. Crucially, both groups of participants exhibited probability-matching behavior to the same extent at a global level of analysis. We suggest that these two forms of probability matching are byproducts of the operation of explicit versus implicit systems.     

Bilingualism aids conflict resolution: evidence from the ANT task

The need of bilinguals to continuously control two languages during speech production may exert general effects on their attentional networks. To explore this issue we compared the performance of bilinguals and monolinguals in the attentional network task (ANT) developed by Fan et al. [Fan, J., McCandliss, B.D. Sommer, T., Raz, A., Posner, M.I. (2002). Testing the efficiency and independence of attentional networks. Journal of Cognitive Neuroscience, 14, 340-347]. This task is supposed to tap into three different attentional networks: alerting, orienting and executive control. The results revealed that bilingual participants were not only faster in performing the task, but also more efficient in the alerting and executive control networks. In particular, bilinguals were aided more by the presentation of an alerting cue, and were also better at resolving conflicting information. Furthermore, bilinguals experienced a reduced switching cost between the different type of trials compared to monolinguals. These results show that bilingualism exerts an influence in the attainment of efficient attentional mechanisms by young adults that are supposed to be at the peak of their attentional capabilities.     

Unconscious task set priming with phonological and semantic tasks

Whether unconscious stimuli can modulate the preparation of a cognitive task is still controversial. Using a backward masking paradigm, we investigated whether the modulation could be observed even if the prime was made unconscious in 100% of the trials. In two behavioral experiments, subjects were instructed to initiate a phonological or semantic task on an upcoming word, following an explicit instruction and an unconscious prime. When the SOA between prime and instruction was sufficiently long (84 ms), primes congruent with the task set instruction led to speedier responses than incongruent primes. In the other condition (36 ms), no task set priming was observed. Repetition priming had the opposite tendency, suggesting the observed task set facilitation cannot be ascribed solely to perceptual repetition priming. Our results therefore confirm that unconscious information can modulate cognitive control for currently active task sets, providing sufficient time is available before the conscious decision.     

Attentional orienting and awareness: evidence from a discrimination task

We used several cue–target SOAs (100, 500, 1000 ms) and three different degrees of cue predictability (Non-predictive-50%, Predictive-75%, Counter-predictive-25%), to investigate the role of awareness of cue–target predictability on cueing effects. A group of participants received instructions about the informative value of the cue, while another group did not receive such instructions. Participants were able to extract the predictive value of a spatially peripheral cue and use it to orient attention, whether or not specific instructions about the predictive value of the cue were given, and no matter their ability to correctly report it in a post-test questionnaire. In the non-predictive block, bad estimators who received no instructions showed regular cueing effects, while good estimators exhibited smaller and non-significant facilitatory effects at the short SOA and an absence of significant IOR at longer SOAs. However, for the instructions group, the pattern of results reversed.     

The effect of overtraining on transfer between tasks involving the same stimulus dimension

Two experiments are reported in which transfer effects between two discrimination tasks are examined following differing amounts of training on the first task. The two tasks were a conditional (successive) discrimination involving black/white cues, and a simultaneous brightness discrimination involving the same black/white cues.

In Experiment I the conditional task was presented first and in Experiment II the simultaneous task was presented first. The results of Experiment I show overall negative transfer which is not directly related to the amount of training. The results of Experiment II, however, reveal positive transfer although again the amount of training produced no significant effect. These seemingly discrepant findings are explained in terms of the difficulty of the conditional task and the development of rigid position stereotypes. It is argued that the concept of frustration-instigated behaviour is necessary to account for the results.     

Inhibition of task set: Converging evidence from task choice in the voluntary task-switching paradigm

This study looked for evidence of task-set inhibition in a voluntary task-switching paradigm. Participants performed one of three tasks on a digit: parity (even or odd), size (less than or greater than 5), or distance (near or far from 5). On each trial, they were allowed to choose which task to perform, with encouragement to perform each task equally often overall and in a random sequence. The question was whether participants would avoid performing a task that they had recently switched away from (e.g., the task performed on trial n22), because the task set was still inhibited. Results confirmed that participants strongly avoided performing the n22 task (e.g., ABA) in favor of performing other tasks (e.g., ABC). This occurred both when participants were required to switch tasks every trial (Experiment 1) and when they were allowed to repeat tasks (Experiment 2). The results suggest that a task set is inhibited during switching to a new task, reducing the likelihood that this task will be selected in the near future.     

No difference between conscious and nonconscious visuomotor control: evidence from perceptual learning in the masked prime task

Negative compatibility effects (NCEs) in the masked-prime paradigm are usually obtained when primes are masked effectively. With ineffective masks-and primes above the perceptual threshold-positive compatibility effects (PCEs) occur. We investigated whether this pattern reflects a causal relationship between conscious awareness and low-level motor control, or whether it reflects the fact that both are affected in the same way by changes in physical stimulus attributes. In a 5-session perceptual learning task, participants learned to consciously identify masked primes. However, they showed unaltered NCEs that were not different from those produced by participants in a control group without equivalent perceptual learning. A control experiment demonstrated that no NCEs occur when prime identification is made possible by ineffective masking. The results suggest that perceptual awareness and low-level motor control are affected by the same factors, but are fundamentally independent of each other.     

Concurrent performance of two memory tasks: evidence for domain-specific working memory systems

Previous studies of dual-task coordination in working memory have shown a lack of dual-task interference when a verbal memory task is combined with concurrent perceptuomotor tracking. Two experiments are reported in which participants were required to perform pairwise combinations of (1) a verbal memory task, a visual memory task, and perceptuomotor tracking (Experiment 1), and (2) pairwise combinations of the two memory tasks and articulatory suppression (Experiment 2). Tracking resulted in no disruption of the verbal memory preload over and above the impact of a delay in recall and showed only minimal disruption of the retention of the visual memory load. Performing an ongoing verbal memory task had virtually no impact on retention of a visual memory preload or vice versa, indicating that performing two demanding memory tasks results in little mutual interference. Experiment 2 also showed minimal disruption when the two memory tasks were combined, although verbal memory (but not visual memory) was clearly disrupted by articulatory suppression interpolated between presentation and recall. These data suggest that a multiple-component working memory model provides a better account for performance in concurrent immediate memory tasks than do theories that assume a single processing and storage system or a limited-capacity attentional system coupled with activated memory traces.     

Positive mood and executive function: evidence from stroop and fluency tasks

Contrasting predictions have been made about the effects of positive mood states on the performance of frontal lobe tests that tap executive functions such as inhibition, switching, and strategy use. It has been argued that positive mood is likely to improve some cognitive processes, particularly those dependent on the frontal cortex and anterior cingulate of the brain. However, there is some evidence that happy mood may impair executive functioning. The current experiments investigated the effects of positive mood on Stoop and fluency tests, which are frequently used to assess executive function. Positive mood impaired performance on a switching condition of the Stroop test, but improved performance on a creative uses test of fluency. The effect of positive mood on an executive task may therefore depend on whether a task is inherently motivating or is impaired by diffuse semantic activation.