Dynamic frequency change influences loudness perception: a central, analytic process.

Three experiments showed that dynamic frequency change influenced loudness. Listeners heard tones that had concurrent frequency and intensity change and tracked loudness while ignoring pitch. Dynamic frequency change significantly influenced loudness. A control experiment showed that the effect depended on dynamic change and was opposite that predicted by static equal loudness contours. In a 3rd experiment, listeners heard white noise intensity change in one ear and harmonic frequency change in the other and tracked the loudness of the noise while ignoring the harmonic tone. Findings suggest that the dynamic interaction of pitch and loudness occurs centrally in the auditory system; is an analytic process; has evolved to take advantage of naturally occurring covariation of frequency and intensity; and reflects a shortcoming of traditional static models of loudness perception in a dynamic natural setting.

Tops are more salient than bottoms.

Past research has verified that observers assume that objects are reliably oriented with respect to a gravitationally centered coordinate system. Observers also appear to attend more to specific parts of objects, like faces, that typically are closer to the top. In the present work, we explored whether or not observers have a generic bias to view tops as being more salient than bottoms. In three experiments, observers indicated whether random shapes appeared to be more similar to comparison shapes that shared identical tops rather than bottoms. Observers exhibited a reliable tendency to match figures with similarly shaped tops. Matching choice was also a function of global shape attributes such as axis of elongation or size. The findings are consistent with the notion that, in nature, tops tend to be the most visible part and to provide the best information with respect to important aspects of objects such as animal intentionality and artifact functionality.

Forward-facing motion biases for rigid and nonrigid biologically likely transformations.

When observers are presented directionally ambiguous motion, they exhibit a bias for experiencing movement in the direction in which shapes appear to face. We examined the influence of rigidity of a shape on the forward-facing bias with stimuli whose directionality is biologically specified. In general, the lack of shape correspondence during a nonrigid transformation should weaken the motion percept and decrease forward-facing bias. In contrast, representational momentum cues associated with a biologically likely nonrigid transformation should enhance the motion percept and increase forward-facing bias. Analysis for both rigid and nonrigid conditions indicated statistically significant forward-facing biases, but strength of bias did not differ significantly. The lack of difference between the two conditions suggests that the transformation was not one which allowed the influence of either consistency of correspondence or representational momentum to dominate and confirms that a comparably sized forward-facing bias can occur with both rigidly and nonrigidly transformed shapes.

The Doppler illusion: the influence of dynamic intensity change on perceived pitch.

Four studies illustrate a new auditory illusion associated with the Doppler effect and demonstrate a new influence of dynamic intensity change on perceived pitch. Experiment 1 confirmed the existence of a popular belief that the pitch of a moving sound source rises as the source approaches. Because there is no corresponding rise in frequency, the authors refer to the perceived pitch rise as the Doppler illusion. Experiment 2 confirmed that the effect occurs perceptually, so the belief in a "naive principle" of physics has a perceptual basis. Experiment 3 confirmed the effect does not occur under matched static conditions. Experiment 4 showed that the influence of dynamic intensity change on perceived pitch occurs outside the realm of Doppler stimuli. The findings support a dynamic dimensional interaction of pitch and loudness, with marked differences in the perception of pitch and loudness under static and dynamic conditions.

How baseball outfielders determine where to run to catch fly balls.

Current theory proposes that baseball outfielders catch fly balls by selecting a running path to achieve optical acceleration cancellation of the ball. Yet people appear to lack the ability to discriminate accelerations accurately. This study supports the idea that outfielders convert the temporal problem to a spatial one by selecting a running path that maintains a linear optical trajectory (LOT) for the ball. The LOT model is a strategy of maintaining "control" over the relative direction of optical ball movement in a manner that is similar to simple predator tracking behavior.

Lateral motion bias associated with reading direction.

We found that when Americans view ambiguous lateral long-range apparent motion, they exhibit a robust bias to experience leftward movement. In successive experiments, right-handers and left-handers, and left-side drivers from Japan equally manifested this leftward bias. However, bilingual viewers whose first language reads from right to left exhibited no lateral bias. Furthermore, the bilingual sample produced a significant correlation between exposure to English and extent of leftward motion bias. The findings provide strong evidence that reading habits can influence directionality in motion perception.

The rising fastball: baseball's impossible pitch.

Batters in professional baseball are confronted with pitches that appear to curve, dip, wobble, or rise. The rising fastball is a pitch where the ball appears to hop up as much as a third of a meter with a sudden increase in speed. Physics experiments confirm that many reported trajectories are possible, but not the rising fastball. The present paper shows how the apparent rise may be explained as a perceptual illusion due to the hitter underestimating original speed of the pitch.

Apparent motion between shapes differing in location and orientation: a window technique for estimating path curvature.

When a shape is alternately presented in two positions differing in both location and orientation, apparent motion tends to be experienced over a curved path. The curvature provides evidence about principles of object motion that may have been internalized in the perceptual system. This study introduces a technique for estimating deviation from a straight path. A shape was alternately presented on the two sides of a visual partition with a "window" just wide enough to accommodate the shape. Observers adjusted the location of the window to maximize the illusion of smooth passage of the shape through the window. In accordance with theoretical expectations, estimated deviations from rectilinear motion increased with the separation between the stimuli in spatial location, angular orientation, and time.