Contingent attentional capture occurs by activated target congruence

Contingent attentional capture occurs when a stimulus property captures an observer's attention, usually related to the observer's top-down attentional set for target-defining properties. In this study, we examined whether contingent attentional capture occurs for a distractor that does not share the target-defining property at a physical level, but does share that property at an abstract level of representation. In a rapid serial visual presentation stream, we defined the target by color (e.g., a green-colored Japanese kanji character). Before the target onset, we presented a distractor that referred to the target-defining color (e.g., a white-colored character meaning "green"). We observed contingent attentional capture by the distractor, which was reflected by a deficit in identifying the subsequent target. This result suggests that because of the attentional set, stimuli were scanned on the basis of the target-defining property at an abstract semantic level of representation.     

The neural correlates of driving performance identified using positron emission tomography

Driving is a complex behavior involving multiple cognitive domains. To identify neural correlates of driving performance, [15O]H2O positron emission tomography was performed using a simulated driving task. Compared with the resting condition, simulated driving increased regional cerebral blood flow (rCBF) in the cerebellum, occipital, and parietal cortices. Correlations between rCBF and measurements of driving performance were evaluated during simulated driving. Interestingly, rCBF in the thalamus, midbrain, and cerebellum were positively correlated with time required to complete the course and rCBF in the posterior cingulate gyrus was positively correlated with number of crashes during the task. These brain regions may thus play roles in the maintenance of driving performance.     

Negative priming and stimulus familiarity: What causes opposite results?

There has been a discrepancy among past studies with regard to the relation between negative priming and familiarity of stimuli. That is, Malley and Strayer (1995; Strayer & Grison, 1999) reported that the more familiar the stimuli were, the larger negative priming became (i.e., a positive correlation), whereas DeSchepper and Treisman (1996; Treisman & DeSchepper, 1996) reported that the less familiar the stimuli were, the larger negative priming became (i.e., a negative correlation). These studies differ not only in their experimental tasks (identification vs. matching) but also in their respective manners of arranging unfamiliar stimuli (pure vs. mixed). In the present study, using an identical set of stimuli, we examined whether these factors caused the opposite results. An identification task with a pure arrangement produced a positive correlation, and a matching task with a mixed arrangement produced a negative correlation. These results suggest that the past opposing results are both replicable and that they have reflected the different causal mechanisms of negative priming.     

Differential effects of physical and psychological stressors on immune functions of rats

To study the effects of different types or durations of stressors on immune functions, male Fischer rats were exposed to chronic physical (electric foot shock) or psychological (non-foot shock) stress induced in the communication box. Superoxide production by alveolar macrophages (AMs), mitogen-induced splenic lymphocyte proliferation, and splenic natural killer (NK) cell cytolysis were examined in vitro. Repeated exposure to physical stress suppressed superoxide production by AMs (-58%, p<0.05 for opsonized zymosan (OZ) and -51%, p<0.05 for phorbol 12-myristate 13-acetate (PMA)), although psychological stress suppressed superoxide production after 24 h of repeated exposures (-40%, p<0.05 for OZ and -47%, p<0.05 for PMA). Acute suppression of the blastic response of splenic lymphocytes was only found in the physical stress group (p<0.05), although the chronic effects were only found in the psychological stress group (p<0.05). NK cell activity was suppressed immediately after the acute physical stress (-30%, p<0.05), but no effects were found in the psychological stress group. These results underline the importance of distinguishing between physical versus psychological stressors when examining the effects of stress on immune functions.     

How do the internal details of the object contribute to recognition?

Object recognition becomes difficult when the main axis of the object is foreshortened. It has previously been reported that this so-called foreshortened disadvantage is larger when the silhouette of the object is presented than when the line drawing of the object is presented. The pronounced foreshortened disadvantage in silhouette recognition indicates that the internal details of the object, which are absent in the silhouette, provide useful information, particularly when the main axis is foreshortened. But the role of these internal details remains controversial. One account for the pronounced disadvantage is that the internal details contribute to the derivation of the main axis. The other account is that internal details provide the distinctive features that are directly matched to the object represented in memory. The aim in the present study was to determine which of these two explanations best accounts for the differential foreshortened disadvantage between line drawings and silhouettes. To reduce the uncertainty regarding the axis orientation, a 3-D arrow indicating the orientation of the main axis was presented as a cue before the object itself was presented. As a result, the difference in the foreshortened disadvantage between silhouettes and line drawings disappeared. This indicated that the pronounced foreshortened disadvantage for silhouettes was caused by a lack of axis information. In other words, the internal details provided the information necessary for axis derivation when the axis was foreshortened.     

Preparation for horizontal or vertical dimensions affects the right-left prevalence effect

When stimulus and response simultaneously vary in both horizontal and vertical dimensions, the stimulus-response compatibility effect is often larger for the horizontal dimension. We investigated the role of preparation for each dimension in this right-left prevalence. In Experiment 1, tasks based on horizontal and vertical dimensions were mixed in random order, and the relevant dimension in each trial was cued with a variable cue-target stimulus onset asynchrony (SOA). A right-left prevalence effect was observed only when participants prepared for the upcoming task. Experiment 2 replicated the absence of the prevalence effect for the simultaneous presentation of cue and target using a fixed SOA of 0 msec. In Experiment 3, the right-left prevalence emerged with a 0-msec SOA when participants prepared for e achdimension basedon its frequency. These resultssuggest that participants' internal set can be greater for the horizontal dimension, leading to the right-left prevalence effect.     

Pre- and Post-head Processing for Single- and Double-Scrambled Sentences of a Head-Final Language as Measured by the Eye Tracking Method

Using the eye-tracking method, the present study depicted pre- and post-head processing for simple scrambled sentences of head-final languages. Three versions of simple Japanese active sentences with ditransitive verbs were used: namely, (1) $\text{ SO }_{\!1\!}\text{ O }_{\!2\!}\text{ V }$ canonical, (2) $\text{ SO }_{\!2\!}\text{ O }_{\!1\!}\text{ V }$ single-scrambled, and (3) $\text{ O }_{\!1\!}\text{ O }_{\!2\!}\text{ SV }$ double-scrambled order. First pass reading times indicated that the third noun phrase just before the verb in both single- and double-scrambled sentences required longer reading times compared to canonical sentences. Re-reading times (the sum of all fixations minus the first pass reading) showed that all noun phrases including the crucial phrase before the verb in double-scrambled sentences required longer re-reading times than those required for single-scrambled sentences; single-scrambled sentences had no difference from canonical ones. Therefore, a single filler-gap dependency can be resolved in pre-head anticipatory processing whereas two filler-gap dependencies require much greater cognitive loading than a single case. These two dependencies can be resolved in post-head processing using verb agreement information.     

Object-based attentional selection and awareness of objects

This study examined whether object-based attentional selection depends on the observer's awareness of objects, using objects defined by perceptual completion. As an indicator of object-based attention, we studied the same-object advantage, where observers respond faster to a target within a cued object than within a noncued object. The same-object advantage was not found in the condition where observers were unaware of the objects (inattentional blindness). On the other hand, the same-object advantage was observed in the condition where observers were aware of the objects. These results suggest that the intensity of object representations can be influenced by observers’ awareness of objects, which affects the occurrence of object-based effects. We propose that attention/inattention (or awareness/unawareness) is graded and observers’ awareness of the objects might serve to boost an otherwise noisy/low signal representation for obtaining object-based effects.     

Preattentive Perception of Multiple Illusory Line-Motion: A Formal Model of Parallel Independent-Detection in Visual Search

The phenomenon referred to as illusory line-motion (ILM; O. Hikosaka, S. Miyauchi, & S. Shimojo, 1993a) has been described as a measure of the local facilitation of attention gradient. However, J. Kawahara, K. Yokosawa, S. Nishida, and T. Sato (1996) have demonstrated a spatially parallel search for an “odd man out” in the ILM direction. Apart from showing preattentive ILM perception in terms of an analogy between line-motion and apparent motion, the authors examined whether ILM perception is possible without attention from another point of view. Four experiments revealed that the ILM target can be detected in parallel without invoking attentional facilitation and invalidated the possible contribution of attentional set in parallel ILM search. Participants were able to correctly detect the ILM target among multiple nontargets, even when the line orientation was changed from trial to trial. The authors' independent-detection model predicted ILM search performance well on several occasions. These findings strongly support a preattentive and stimulus-driven explanation of ILM perception.     

Discrete cortical regions associated with the musical beauty of major and minor chords

Previous research has demonstrated that the degree of aesthetic pleasure a person experiences correlates with the activation of reward functions in the brain. However, it is unclear whether different affective qualities and the perceptions of beauty that they evoke correspond to specific areas of brain activation. Major and minor musical keys induce two types of affective qualities--bright/happy and dark/sad--that both evoke aesthetic pleasure. In the present study, we used positron emission tomography to demonstrate that the two musical keys (major and minor) activate distinct brain areas. Minor consonant chords perceived as beautiful strongly activated the right striatum, which has been assumed to play an important role in reward and emotion processing, whereas major consonant chords perceived as beautiful induced significant activity in the left middle temporal gyrus, which is believed to be related to coherent and orderly information processing. These results suggest that major and minor keys, both of which are perceived as beautiful, are processed differently in the brain.