Elevating Baseline Activation Does Not Facilitate Reading of Unattended Words

Previous studies have disagreed the extent to which people extract meaning from words presented outside the focus of spatial attention. The present study, examined a possible explanation for such discrepancies, inspired by attenuation theory: unattended words can be read more automatically when they have a high baseline level of activation (e.g., due to frequent repetition or due to being expected in a given context). We presented a brief prime word in lowercase, followed by a target word in uppercase. Participants indicated whether the target word belonged to a particular category (e.g., "sport"). When we drew attention to the prime word using a visual cue, the prime produced substantial priming effects on target responses (i.e., faster responses when the prime and target words were identical or from the same category than when they belonged to different categories). When prime words were not attended, however, they produced no priming effects. This finding replicated even when there were only 4 words, each repeated 160 times during the experiment. Even with a very high baseline level of activation, it appears that very little word processing is possible without spatial attention

Mindfulness and Divergent Thinking: The Value of Heart Rate Variability as an Objective Manipulation Check

Abstract Mindfulness (MF) is a form of mental training that has been linked to increased creativity in problem-solving. Most MF studies recruit participants interested in meditation, and thus are biased towards positive effects. Participants in this study (n = 73) therefore signed up for "mental training," not "mindfulness meditation"; the vast majority (54) had little to no prior meditation experience. This is also the first such experiment to use an objective measure of MF (coherence, a physiological correlate of MF that can be indexed by heart rate variability or HRV) as a manipulation check. Participants were randomly assigned to either MF training or a control condition (a memory exercise), and completed a test of divergent thinking (Unusual Uses Task) before and after mental training. Coherence was significantly higher in the MF group and heart rate was significantly lower in the MF group

An Electrophysiological Study of Attention Capture by Salience: Does Rarity Enable Capture?

Several behavioral studies have suggested that rarity is critical for enabling irrelevant, salient objects to capture attention. We tested this hypothesis using the N2pc, thought to reflect attentional allocation. A cue display was followed by a target display in which participants identified the letter in a specific color. Experiment 1 pitted rare, irrelevant abrupt onset cues (appearing on only 20% of trials) against target-relevant color cues. The relevant color cue produced large N2pc and cue validity effects, even when competing with a rare, salient, simultaneous abrupt onset. Similar results occurred even when abrupt onset frequency was reduced to only 10% of trials (Experiment 2). Experiment 3 examined rare, irrelevant color singleton cues (20% of trials). Despite being rare and salient, these singleton cues produced no N2pc or cue validity effect, indicating little attentional capture. Experiment 4 greatly increased color cue salience by adding 4 background boxes, increasing color contrast, and tripling the cue display duration (from 50 to 150 ms). Small cue validity and N2pc effects were obtained, but did not strongly depend on degree of rarity (20% vs. 100%). We argue that rarity by itself is neither necessary nor sufficient to produce attention capture.Keywords: Visual attention, N2pc, Attention captureKeywords: Visual attention, N2pc, Attention captur

An Electrophysiological Dual-Task Study of Visual Word Processing without Task Switching

A previous dual-task study (Lien, Ruthruff, Cornett, Goodin, & Allen, 2008) provided evidence that people have difficulty identifying words while central attention is devoted to another non-word task. In that study, participants performed an auditory Task 1 regarding tone pitch and a visual word Task 2. However, it’s possible that the real obstacle to word identification was not the lack of central attention, but rather the required task switch. The present study therefore examined this issue by using a dual-task paradigm in which participants performed essentially the same word task for both Task 1 and Task 2 (i.e., there was no task switch). We measured the N400 effect elicited by Task-2 word, a measure of whether participants detected a mismatch between the word and the current semantic context. The N400 effect can occur only if a word has been identified. We found that the N400 effect was strongly attenuated for Task-2 words presented nearly simultaneously with Task-1 words. This finding suggests that, even without task switching, words still cannot be identified without central attentional resources.Keywords: Attention, Word Processing, Dual Tas

Attention Capture While Switching Search Strategies: Evidence for a Breakdown in Top-Down Attentional Control

Whereas capture experiments typically repeat a single task many times, real world cognition is characterized by frequent switching. Lien, Ruthruff, and Johnston (2010) reported that the attentional control system can rapidly and fully switch between different search settings (e.g., red to green), with no carryover and no inter-trial priming. The present study examined whether this impressive flexibility is possible even when the switch is not between different features along the same dimension, but between mutually incompatible search modes. On each trial, participants were prompted to find and identify the letter that was in a specific color (feature search mode) or was uniquely colored (singleton search mode). Within each block, search mode was either pure or mixed; the mixed blocks contained a fixed AABB search sequence (singleton-singleton-feature- feature) in Experiment 1 and a random sequence in Experiment 2. The target display was preceded by a non-informative cue display containing a non-target color singleton. In pure feature search blocks, these irrelevant singleton cues were generally unable to capture attention, replicating previous findings of “contingent capture.” In mixed blocks, however, irrelevant color singletons captured attention on feature search trials. This breakdown indicates a limitation in the sharpness of attentional control following mode switches, which might be common in the real world.Keywords: Cognitive Control and Switching, Visual Search Strategy, Attention CaptureKeywords: Cognitive Control and Switching, Visual Search Strategy, Attention Captur

On the limits of advance preparation for a task switch: Do people prepare all the task some of the time or some of the task all the time

This study investigated the nature of advance preparation for a task switch, testing two key assumptions of De Jong's (2000) failure-to-engage theory were tested: (a) task-switch preparation is all-or-none, and (b) preparation failures stem from not utilizing available control capabilities. In all three experiments switch costs varied dramatically across the individual S-R pairs of the tasks -virtually absent for one S-R pair but large for other S-R pairs. These findings indicate that, across trials, task preparation was not allor-none but rather was consistently partial (full preparation of some S-R pairs but not others). In other words, people do not prepare all of the task some of the time, but rather prepare some of the task all of the time. Experiments 2 and 3 produced substantial switch costs even though time deadlines provided strong incentives for optimal advance preparation. Thus, there was no evidence that people have a latent capability to fully prepare a task switch

Capture by Fear Revisited: An Electrophysiological Investigation

The present study, using a cuing paradigm, reexamined the claim of an attentional bias toward fearful faces. In Experiment 1, participants searched a target display for a letter in a specific color. This target display was preceded by a non-informative cue display, which contained colored boxes (one in the target color and one in the distractor color) or emotional faces (one fearful face and one neutral face). Each cue could appear in the same location as the target (validly cued) or different (invalidly cued). To determine whether the cues captured attention, we used an electrophysiological measure of spatial attention known as the N2pc effect. The target color cue produced a substantial N2pc effect and a robust cue validity effect on behavioral data, indicating capture by stimuli that match what participants are looking for. However, neither effect was present for the task-irrelevant fearful face cue. These findings suggest that negative stimuli (such as fearful facial expressions) do not generally have the inherent power to capture spatial attention against our will. Experiment 2 showed that these same fearful faces could capture attention when fearful expressions became task-relevant. Thus, the critical determinant of capture appears to be task-relevance, rather than perceived threat.Keywords: Attention Capture, N2pc, Visual Attention, Emotion Perceptio