Fumie Sugimoto

Somatosensory P2 reflects resource allocation in a game task: Assessment with an irrelevant probe technique using electrical probe stimuli to shoulders

The present study investigated whether event-related brain potentials (ERPs) elicited by task irrelevant somatosensory stimuli to the shoulders reflect the amount of processing resources allocated to a game task. In the experiment, electrical stimuli were presented to the right (or left) shoulder with a high probability (80%) and to the other shoulder with a low probability (20%) while participants were performing a driving simulation game. The deviant low-probability stimuli elicited somatosensory P2, and this P2 amplitude decreased when the task was difficult. The results show that the ERPs for somatosensory stimuli to the shoulders can reflect the amount of resources deployed even when the stimuli are ignored. This is a useful method for the evaluation of mental workloads in complex circumstances because it does not interfere with inputs of auditory or visual information or operations using the limbs.

Neural correlates of error processing reflect individual differences in interoceptive sensitivity

Although self-monitoring is an important process for adaptive behaviors in multiple domains, the exact relationship among different internal monitoring systems is unclear. Here, we aimed to determine whether and how physiological monitoring (interoception) and behavioral monitoring (error processing) are related to each other. To this end we examined within-subject correlations among measures representing each function. Score on the heartbeat counting task (HCT) was used as a measure of interoceptive awareness. The amplitude of two event-related potentials (error-related negativity [ERN] and error-positivity [Pe]) elicited in error trials of a choice-reaction task (Simon task) were used as measures of error processing. The Simon task presented three types of stimuli (objects, faces showing disgust, and happy faces) to further examine how emotional context might affect inter-domain associations. Results showed that HCT score was robustly correlated with Pe amplitude (the later portion of error-related neural activity), irrespective of stimulus condition. In contrast, HCT score was correlated with ERN amplitude (the early component) only when participants were presented with disgust-faces as stimuli, which may have automatically elicited a physiological response. Behavioral data showed that HCT score was associated with the degree to which reaction times slowed after committing errors in the object condition. Cardiac activity measures indicated that vigilance level would not explain these correlations. These results suggest a relationship between physiological and behavioral monitoring. Furthermore, the degree to which behavioral monitoring relies on physiological monitoring appears to be flexible and depend on the situation.

Why Are There Failures of Systematicity? The Empirical Costs and Benefits of Inducing Universal Constructions

Systematicity is a property of cognition where capacity for certain cognitive abilities implies capacity for certain other (structurally related) cognitive abilities. This property is thought to derive from a capacity to represent/process common structural relations between constituents of cognizable entities, however, systematicity may not always materialize in such admissible contexts. A theoretical challenge is to explain why systematicity fails to materialize in contexts that allow the realization (e.g., by induction) of common structure (universal construction). We hypothesize that one cause of failure arises when the potential gain afforded by induction of common structure is overshadowed by the immediate benefit of learning the task as independent stimulus-response associations. This hypothesis was tested in an experiment that required learning two series of pair maps that involved products (universal construction), or non-products (control) of varied size: the number of unique cue/target elements (three to six) constituting pairs. Each series was learned in either ascending or descending order of size. Only performance on the product series was affected by order: systematicity was obtained universally in the descend group, but only on large sets in the ascend group, as revealed by the significant order × size interaction for errors in the product condition, F(3, 87) = 3.38, p < 0.05. Smaller maps are more easily learned without inducing the common product structure, which is more readily observable with larger maps: larger maps provide more evidence for relationships between stimulus dimensions that facilitate the discovery of the common structure. The new challenge, then, is to explain the systematic learnability of stimulus-response maps, i.e., second-order systematicity.

Aftermath of 3/11: Earthquakes and involuntary attentional orienting to sudden ambient sounds

Due to the Great East Japan Earthquake on 11 March 2011 and the following long-term earthquake swarm, many people living in the earthquake-affected areas have developed mental stress, even though clinically-diagnosable symptoms may not be apparent. Concurrently, many unusual reports have emerged in which persons complain of abnormally increased sensitivity to sudden ambient sounds during their daily lives (e.g., the sound of the washing machine on spin cycle). By recording event-related potentials to various sudden ambient sounds from young adults living in the affected areas, we found that the level of earthquake-induced mental stress, as indexed by the hyperarousal symptoms of posttraumatic stress disorder, was positively related to the magnitude of P3a to sudden ambient sounds. These results reveal a strong relationship between mental stress and enhanced involuntary attentional orienting in a large majority of trauma-exposed people without diagnosable symptoms.

Dual-Routes and the Cost of Determining Least-Costs

Theories of cognition that posit complementary dual-route processes afford better fits to the data when each route explains a part of the data not explained by the other route. However, such theories must also explain why each route is invoked, lest one can fit any data set with enough alternatives. One possible explanation is that route selection is based on a least-cost principle: the route that requires fewer cognitive resources (including time) relative to the goal at hand. We investigated this explanation with a dual-display version of visual search, where the target could be identified via opposing (easy or hard forms of) feature and conjunction search conditions. The data support a contextualized version of the least-cost principle in that the cost of computing least-cost also influences route selection: participants assessed alternatives, but only when the cost of that assessment was relatively low.

Increased visual task difficulty enhances attentional capture by both visual and auditory distractor stimuli

Previous studies using a three-stimulus oddball task have shown the amplitude of P3a elicited by distractor stimuli increases when perceptual discrimination between standard and target stimuli becomes difficult. This means that the attentional capture by the distractor stimuli is enhanced along with an increase in task difficulty. So far, the increase of P3a has been reported when standard, target, and distractor stimuli were presented within one sensory modality (i.e., visual or auditory). In the present study, we further investigated whether or not the increase of P3a can also be observed when the distractor stimuli are presented in a different modality from the standard and target stimuli. Twelve participants performed a three-stimulus oddball task in which they were required to discriminate between visual standard and target stimuli. As the distractor stimuli, either another visual stimulus or an auditory stimulus was presented in separate blocks. Visual distractor stimuli elicited P3a, and its amplitude increased when visual standard/target discrimination was difficult, replicating previous findings. Auditory distractor stimuli elicited P3a, and importantly, its amplitude also increased when visual standard/target discrimination was difficult. This result means that attentional capture by distractor stimuli can be enhanced even when the distractor stimuli are presented in a different modality from the standard and target stimuli. Possible mechanisms and implications are discussed in terms of the relative saliency of distractor stimuli, influences of temporal/spatial attention, and the load involved in a task.

Temporal attention is involved in the enhancement of attentional capture with task difficulty: an event-related brain potential study

In a three-stimulus oddball task, the amplitude of P3a elicited by deviant stimuli increases with an increase in the difficulty of discriminating between standard and target stimuli (i.e. task-difficulty effect on P3a), indicating that attentional capture by deviant stimuli is enhanced with an increase in task difficulty. This enhancement of attentional capture may be explained in terms of the modulation of modality-nonspecific temporal attention; that is, the participant’s attention directed to the predicted timing of stimulus presentation is stronger when the task difficulty increases, which results in enhanced attentional capture. The present study examined this possibility with a modified three-stimulus oddball task consisting of a visual standard, a visual target, and four types of deviant stimuli defined by a combination of two modalities (visual and auditory) and two presentation timings (predicted and unpredicted). We expected that if the modulation of temporal attention is involved in enhanced attentional capture, then the task-difficulty effect on P3a should be reduced for unpredicted compared with predicted deviant stimuli irrespective of their modality; this is because the influence of temporal attention should be markedly weaker for unpredicted compared with predicted deviant stimuli. The results showed that the task-difficulty effect on P3a was significantly reduced for unpredicted compared with predicted deviant stimuli in both the visual and the auditory modalities. This result suggests that the modulation of modality-nonspecific temporal attention induced by the increase in task difficulty is at least partly involved in the enhancement of attentional capture by deviant stimuli.