Impaired visual perceptual accuracy in the upper visual field induces asymmetric performance in position estimation for falling and rising objects

Abstract

Humans can estimate the time and position of a moving object's arrival. However, numerous studies have demonstrated superior position estimation accuracy for descending objects compared with ascending objects. We tested whether the accuracy of position estimation for ascending and descending objects differs between the upper and lower visual fields. Using a head-mounted display, participants observed a target object ascending or descending toward a goal located at 8.7° or 17.1° above or below from the center of the monitor in the upper and lower visual fields, respectively. Participants pressed a key to match the time of the target's arrival at the goal, with the gaze kept centered. For goals (8.7°) close to the center, ascending and descending objects were equally accurate, whereas for goals (17.1°) far from the center, the ascending target's position estimation in the upper visual field was inferior to the others. Targets moved away from the center for goals further from the center and closer to the center for goals nearer to the center. As the positional accuracy of ascending and descending objects was not assessed for each of the four goals, it remains unclear which was more important for impaired accuracy: the proximity of the target position or direction of the upward or downward motion. However, taken together with previous studies, we suggest that estimating the position of objects moving further away from the central fovea of the upper visual field may have contributed to the asymmetry in position estimation for ascending and descending objects.

Figure 1.

Experimental design. (A) Experimental setup. All participants sat in the chair and put their chins on the chinrest. An HMD was used to show the visual stimulus. Participants placed the index finger of their dominant hand on the keypad. (B) Virtual reality scenes depicted the following movements from the left side of the view: Upper-Ascend, Upper-Descend, Lower-Ascend, and Lower-Descend. The magenta lines indicate the direction of the ball's target motion in each VR scene. The red dot was the fixation point. (C) Experimental schedule and presentation order.

Figure 2.

Eye position results and number of excluded data. The horizontal and vertical axes represent the horizontal and vertical eye positions (°), respectively. Red squares indicate the criteria for an acceptable fixation area. The blue and gray dots represent the eye position data points during the target motion in each trial. A total of 1,608 data points (670 ms × 120 Hz × 20 trials) are plotted in each figure. The blue dots represent acceptable eye positions during the target motion in each trial. The gray dots represent unacceptable eye positions, where the eye positions moved more than 3° vertically during the target motion. The circle in A indicates the goal position under the Lower-Ascend condition. (A) Horizontal and vertical eye positions of Participant 1. (B) Horizontal and vertical eye positions of Participant 2.

Figure 3.

The mean TDs for ascending and descending targets in the upper and lower visual fields. The vertical axis on the left side indicates the difference between the arrival times at the goal (670 ms) and keypress times. The right side of the vertical axis indicates the keypress time. The orange and blue bars represent the mean TDs for the ascending and descending targets, respectively. The orange and blue bars on the left side represent the upper visual conditions (Upper-Ascend and Upper-Descend scenes), and those on the right side represent the lower visual conditions (Lower-Ascend and Lower-Descend scenes). Error bars indicate standard error. Asterisks indicate the results of post hoc analysis using Tukey's HSD (*p < 0.05, **p < 0.01).

Figure 4.

Each participant's result of mean TD between ascending and descending targets in the upper and lower visual fields. The horizontal axes in A and B indicate the TD in the Lower-Ascend and Lower-Descend scenes, respectively. The vertical axes in A and B indicate the TD in the Upper-Ascend and the Upper-Descend scenes, respectively. The dashed diagonal line represents the equal performance of arrival time estimation between the upper and lower visual fields. (A) Individual mean TDs for ascending motion in the upper and lower visual fields. The orange dots represent the individual results of the mean TDs for ascending targets. (B) Individual mean TDs for descending motion in the upper and lower visual fields. The blue dots represent the individual results of the mean TDs for the descending targets. The green dots in A and B represent the average of the individual mean TDs.

Figure 5.

Mean TD in each trial under each VR scene. The horizontal axes in all four figures represent the trial number (1st–20th). The left vertical axes in all four figures represent the mean TD for each trial (gray dots). The right vertical axes in all four figures indicate the mean TD for the beginning (1st–7th), middle (8th–13th), and end (14th–20th) phases (blue dots). (A) Upper-Ascend scene. (B) Upper-Descend scene. (C) Lower-Ascend scene. (D) Lower-Descend scene. Error bars indicate the standard error.