While the percentage of older people in our society is steadily increasing, knowledge about perceptual changes during healthy aging is still limited. We investigated age effects on visual motion perception in order to differentiate between general decline and specific vulnerabilities. A total of 119 subjects ranging in age from 20 to 82 years participated in our study. Perceptual thresholds for different types of motion information, including translational motion, expanding radial flow, and biological motion, were determined. Results revealed a substantial increase of thresholds for translational motion with age. Biological motion perception was only moderately affected by age. For both motion types, threshold elevation seemed to develop gradually with age. In contrast, we found stable radial flow analysis across lifespan. There was no evidence that age effects were dependent on gender. Results demonstrate that visual capabilities are not equally prone to age-related decline. Surprisingly, higher motion complexity might not be necessarily associated with more pronounced perceptual constraints. We suggest that differential age effects on the perception of specific motion types might indicate that specialized neuronal processing mechanisms differ in their vulnerability to physiological changes during aging.

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Research on functional changes across the adult lifespan has been dominated by studies related to cognitive processes. However, it has become evident that a more comprehensive approach to behavioral aging is needed. In particular, our understanding of age-related perceptual changes is limited. Visual motion perception is one of the most studied areas in perceptual aging and therefore, provides an excellent domain on the basis of which we can investigate the complexity of the aging process. We review the existing literature on how aging affects motion perception, including different processing stages, and consider links to cognitive and motor changes. We address the heterogeneity of results and emphasize the role of individual differences. Findings on age-related changes in motion perception ultimately illustrate the complexity of functional dynamics that can contribute to decline as well as stability during healthy aging. We thus propose that motion perception offers a conceptual framework for perceptual aging, encouraging a deliberate consideration of functional limits and resources emerging across the lifespan.

While many aspects of human vision at low light levels have been studied in great detail, motion perception has rarely been investigated so far. Here we address differential effects of light level on the perception of coherent motion, heading from radial flow, and biological motion. We determined detection thresholds under photopic, mesopic, and scotopic conditions. Results indicate that the perception of specific motion types differs in vulnerability to changes in light level. Thresholds for coherent motion and heading from radial flow increased monotonically from photopic to mesopic and scotopic light levels. We suppose that observed deficits are due to temporal pooling under rod-dominated vision. In contrast, detection thresholds for biological motion, which is distinguished by temporal dynamics and a specific spatial distribution of nearby signals, were exclusively elevated under mesopic conditions. Thresholds under scotopic conditions matched those under photopic conditions. Selective constraints under mesopic conditions might be explained by a detrimental interaction of rod and cone vision as well as by activity of different rod pathways. Findings suggest that very early retinal signal processing can have complex effects on the perception of different motion types, which is generally considered to rely on cortical areas.

Anomalous motion illusions represent a popular class of illusions and several studies have made an effort to explain their perception. However, understanding is still inconsistent. Age-related differences in susceptibility to illusory motion may contribute to further clarification of the underlying processing mechanisms. We investigated the effect of age on the perception of four different anomalous motion illusions. The Enigma illusion, the Rotating-Snakes illusion, the Pinna illusion, and the Rotating-Tilted-Lines illusion were tested on a total of one hundred and thirty-nine participants covering an age range from 3 to 82 years. In comparison with young adults, children showed a lower likelihood of perceiving motion in all illusions with the exception of the Rotating-Tilted-Lines illusion. For adult subjects, we found significant age effects in the Rotating-Snakes illusion and the Rotating-Tilted-Lines illusion: occurrence of the illusory effect decreased with age. The other two illusions turned out to be unaffected by aging. Finally, intercorrelations between different motion illusions revealed that only the Pinna illusion and the Rotating-Tilted-Lines illusion correlated significantly with each other. The results confirm that anomalous motion illusions should not be considered as a homogeneous group. Possible links between perceptual data and neurophysiological changes related to age are discussed. Perceptual differences due to age provide the opportunity to improve our understanding of illusory motion and point to specific underlying mechanisms.