This study investigated the effect of exogenous spatial attention on auditory information processing. In Experiments 1, 2 and 3, temporal order judgment tasks were performed to examine the effect. In Experiment 1 and 2, a cue tone was presented to either the left or right ear, followed by sequential presentation of two target tones. The subjects judged the order of presentation of the target tones. The results showed that subjects heard both tones simultaneously when the target tone, which was presented on the same side as the cue tone, was presented after the target tone on the opposite side. This indicates that spatial exogenous attention was aroused by the cue tone, and facilitated subsequent auditory information processing. Experiment 3 examined whether both cue position and frequency influence the resulting information processing. The same effect of spatial attention was observed, but the effect of attention to a certain frequency was only partially observed. In Experiment 4, a tone fusion judgment task was performed to examine whether the effect of spatial attention occurred in the initial stages of hearing. The result suggests that the effect occurred in the later stages of hearing.

Two experiments were carried out to investigate duration estimation of rotating-spot-patterns under a situation with the minimum cue to frequency. Twenty-four undergraduates were used as subjects in each experiment. The magnitude estimation method was used in Experiment I, where for a constant duration, the estimate of the duration increased with the velocity of the rotation of the pattern except for that of stationary pattern, where the duration was estimated longer than that for the slowest of the moving patterns. The same tendencies were observed in Experiment II, where the magnitude production method was used. The multiple regression analysis suggested that the best model which explains the velocity effects upon time estimation was a multiplicative one and contained a quadratic function of logarithmically transformed velocity in both experiments. The explanatory principles of the velocity effects and the validity of the model were discussed in the light of past studies.

The minimum temporal thresholds for absolute motion detection were measured for sinusoidal grating patterns in foveal vision. Test patterns of relatively low temporal frequencies and low velocities were examined. The thresholds clearly decreased with test velocities rather than with test temporal frequencies. Modified velocity-time reciprocity was observed (i.e. the relationship between test velocity and temporal thresholds was described by a simple equation including two constants which indicate temporal and spatial limits). The temporal constant was about 35 ms and the spatial constant was about 1 min of arc. These constants are thought to provide the basic constraints on motion detection.

The present study investigated the division of attention between different visual attributes, which is a cognitive function implicated in the selection of information in a given condition. To examine the underlying mechanisms, we focused on motion and color as visual attributes. In Experiment 1, performance on single- and dual-judgment for motion and color of dynamic random dot patterns presented in a restricted visual field was examined under different priority conditions. Accuracy was the same for single- and dual-task conditions, and the attention operating characteristic (AOC) analysis indicated that motion and color perception do not share the same processing capacity. In addition, correlation analysis indicated that, on a trial-by-trial basis, performance on motion and color was considerably independent. In Experiment 2, a brief lateral cue preceded the dynamic random dot patterns. The cue affected only motion-judgment, even under dual-task conditions of motion and color. These results suggest that dividing attention between motion and color involves independent mechanisms.

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