Infant Perception of Surface Texture and Relative Height as Distance Information: A Preferential-Reaching Study

Development of Three-Dimensional Perception in Human Infants

The play of light on the retina contains multiple sources of information about the three-dimensional (3D) structure of the world. Some of the best information is derived from differencing operations that act on the images that result from the two eyes’ laterally displaced vantage points. Other information is available in systematic retinal patterns of local texture and motion cues. This article describes what is currently known about the development of sensitivity to these binocular and monocular cues for depth in human infants, and it places the results in the context of what is known about the underlying neural mechanisms from work in nonhuman primates and human neuroimaging studies.

The ground is dominant in infants' perception of relative distance

When making relative distance judgments, adults attend to information provided by the ground surface and generally ignore information provided by ceiling surfaces. In the present study, we asked whether this ground dominance effect is present in infancy. Groups of 5- and 7-month-old infants viewed a display depicting textured ground and ceiling surfaces. Two toys, which were attached to vertical rods, were affixed to the display. The toys/rods were positioned so that one toy was specified as being nearer by the ground surface but farther away by the ceiling surface, while the other toy was specified as being farther away by the ground surface but nearer by the ceiling surface. Under monocular viewing conditions, the infants in both age groups reached preferentially for the toy that was specified as being nearer by the ground surface. This effect was significantly stronger than that observed under binocular viewing conditions. The findings indicate that the infants responded to the distance information provided by the ground surface to a greater extent than to information provided by the ceiling.

Infants' sensitivity to pictorial depth cues: a review and meta-analysis of looking studies

This paper reviews habituation-dishabituation and preferential-looking studies on the emergence of sensitivity to pictorial depth cues in infancy. This research can be subdivided into two groups. While one group of studies has established responsiveness to pictorial depth cues at 3-5 months of age, the other has found that the ability to extract pictorial 3D information emerges at about 6 months. In the former, young infants were tested for their ability to distinguish between displays that differ in spatial information provided by pictorial depth cues. The results of these studies might demonstrate that 3-5-month-old infants perceive spatial layout from pictorial cues. It is possible, however, that the infants in these studies responded primarily to low-level, two-dimensional stimulus differences. In contrast, the second group of studies controlled for the potential influence of lower-level stimulus features on the infants' experimental performance and more unambiguously demonstrated sensitivity to pictorial depth information in infants 6 months of age and older. In sum, the divergent findings of studies in this area may be resolved by assuming substantial developmental progress in infant sensitivity to pictorial depth cues during the first months of life.

Die Entwicklung der räumlichen Wahrnehmung im Säuglingsalter: Eine Positionsbestimmung

Zusammenfassung. In den vergangenen Jahrzehnten ist eine Vielzahl experimenteller Studien mit dem Ziel durchgeführt worden, den Zeitpunkt der Entstehung der räumlichen Wahrnehmung im ersten Lebensjahr aufzuspüren. Ein Problem dieser Forschungsarbeiten besteht darin, dass sie auf keine einheitlichen Altersangaben hin konvergieren und so keine sicheren Schlussfolgerungen darüber zulassen, ab wann genau die jeweilige Wahrnehmungsleistung vorhanden ist. Insbesondere im Bereich der bildhaften Tiefenwahrnehmung gibt es eine vermeintliche Diskrepanz in den Ergebnissen von Studien, in denen die Methode des präferentiellen Greifens zur Anwendung kommt, und Studien, in denen das kindliche Blickverhalten beobachtet wird. Aufgabe der Forschung ist daher die Entwicklung und Anwendung von Heuristiken, mit deren Hilfe eine Klärung der Faktoren erfolgen kann, die für derartige unterschiedliche Befundlagen verantwortlich sind. Zu diesen Heuristiken zählen das Verfahren der metaanalytischen Auswertung vorhandener Ergebnisse sowie die Anwendung unterschiedlicher Untersuchungsmethoden und Versuchsdesigns auf einen Inhaltsbereich. Am Beispiel der bildhaften Tiefenwahrnehmung wird dargestellt, dass eine metaanalytische Vorgehensweise die Theorienbildung vorantreiben kann. Zudem werden unterschiedliche experimentelle Designs und Techniken der Datenerhebung skizziert und in ihrer Rolle für die Forschung erläutert.

The Relative Contribution of Relative Height, Linear Perspective, and Texture Gradients to Pictorial Depth Perception in 7-Month-Old Infants

In the current preferential-reaching experiments, 7-month-olds were tested for their ability to respond to a combination of relative height and texture gradients. The infants were presented with a display in which these pictorial depth cues specified that two toys were at different distances. The experimental displays differed from the textured surfaces employed in earlier studies in that linear perspective of the contours of the texture elements was omitted. Experiment A shows that the infants still preferred to reach for the apparently nearer toy under monocular, but not binocular, viewing conditions, indicating that they responded to the pictorial depth cues. In experiment B, relative height and texture provided the infants with conflicting information for depth. Here, relative height outperformed texture information. A statistical comparison between the experiments as well as systematic comparisons with experimental conditions from an earlier study (Hemker et al, 2010 Infancy15 6 – 27) revealed that texture gradients, unlike linear perspective, neither enhanced nor weakened the effect exerted by relative height. In sum, 7-month-old infants are obviously more sensitive to relative height and to the linear perspective of the surface contours than to the texture gradients of compression, perspective, and density.