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E L Leeuwenberg

Publications and source records attributed to E L Leeuwenberg.

9 recordsLinked to original sources
PubMed1997

In support of hierarchy in object representations.

The descriptive minimum principle states that the preferred interpretation of a pattern is reflected by the simplest representation of that pattern. Such a simplest representation generally has a hierarchical structure. The pattern component represented at the highest hierarchical level is said to constitute the "superstructure" of the pattern, and pattern components represented at lower levels are said to constitute the "subordinate" structure. The primed-matching paradigm has been employed in two experiments to test whether superstructures of three-dimensional objects are perceptually more dominant than subordinate structures. In the first experiment, the test pairs consisted of two-dimensional line drawings of three-dimensional objects; each prime was a two-dimensional face of such an object, corresponding to either the superstructure or the subordinate structure. Two priming conditions were employed. In the "literal" condition, the object face was presented as it appeared in the drawing of the object (physical similarity). In the "frontal" condition, the object face was presented in the frontal-parallel plane (representational similarity). Object matching was found to be facilitated more by priming superstructures than by priming subordinate structures. In the second experiment, the order was reversed; the test pairs were composed of the object faces and the object drawings wee taken as primes. Again, there were facilitating effects for both superstructures and subordinate structures, but this time without differentiation between superstructures and subordinate structures.

Adult↗
PubMed1996

Goodness of visual regularities: a nontransformational approach.

Until recently, the transformational approach provided the only available formal analysis of visual regularities like repetition and mirror symmetry. This theoretical study presents a new analysis, based on the recently developed concept of holographic regularity. This concept applies to the intrinsic character of regularity and specifies the unique formal status of perceptually relevant regularities. The crucial point is that the two analyses imply the same structure for repetition but a different structure for mirror symmetry. Transformationally, mirror symmetry is an all-or-nothing property, whereas holographically, it is a graded property. This difference pervades the understanding of both perfect regularities and perturbed regularities. Whereas the transformational approach explains hardly any goodness phenomenon, the holographic approach explains a wide variety of goodness phenomena in a coherent way that is ecologically plausible as well.

Attention↗
PubMed1995

Competing global and local completions in visual occlusion.

In visual occlusion 2 amodal-completion tendencies occur frequently. One tendency leads toward the simplest completed shape (a global completion) and the other to a shape for which the completion itself is as simple as possible (a local completion). Two experimental paradigms were used to test the strengths of these completion tendencies: a drawing task and a simultaneous matching task. The experimental results support the notion that the preference for either a global or a local completion is the consequence of a competition between interpretations. Finally, the authors discuss how the preference for a completion can be predicted by a model that is based on a quantification of both global and local aspects.

Adult↗
PubMed1995

Multiple completions primed by occlusion patterns.

There is a strong tendency to complete a partly occluded shape. Two types of pattern completion, global and local, are frequently reported. By means of the primed-matching paradigm, it has previously been shown that global completions are prevalent for stimuli in which regularity is abundantly present. In our study the primed-matching paradigm is applied to such stimuli in order to find out whether the rival local completion is generated as well. Therefore anomalous completions are added to the experimental design. Priming effects both on global and on local completions are compared with priming effects on those anomalous completions. The data indeed suggest that the occlusion patterns evoked not only a global but also a local completion.

Fixation, Ocular↗
PubMed1992

Serial pattern complexity: irregularity and hierarchy.

In perception research, various models have been designed for the encoding of, for example, visual patterns, in order to predict the human interpretation of such patterns. Each of these encoding models provides a few coding rules to obtain codes for a pattern, each code expressing regularity and hierarchy in that pattern. Some of these models employ the minimum principle which states that the human interpretation of a pattern is reflected by the simplest code for that pattern, ie the simplest code according to a given complexity metric. In this paper a new complexity metric is proposed. This metric is based on a formal analysis of the concept of regularity. Some conclusions of this analysis are sketched. The new metric does not depend on artifacts of the coding rules. It accounts for the amounts of irregularity and hierarchy as represented in a code of a pattern, such that these two amounts can be added to determine the complexity of a code. An experiment is discussed that shows that the new metric performs significantly better than the metrics used previously. In particular, the new metric predicts more local pattern organizations than the old metrics. This implies that various local pattern organizations do not falsify the minimum principle anymore.

Attention↗
PubMed1988

Hidden figures are ever present.

Preference judgments about alternative interpretations of unambiguous patterns can be explained in terms of a rivalry between a preferred and a second-best interpretation (cf. Leeuwenberg & Buffart, 1983). We tested whether this second-best interpretation corresponds to a suppressed but concurrently present interpretation or whether it merely reflects an alternative view that happens to be preferred less often. Two patterns were present immediately following each other with a very short onset asynchrony: a complete pattern and one out of three possible subpatterns of it, corresponding to the best, the second best, or an odd interpretation of the complete pattern. Subjects indicated which subpattern was presented by choosing among the three subpatterns shown after each trial. The scores, corrected for response-bias effects, indicated a relative facilitation of the second-best interpretation, in agreement with its predicted "hidden" presence. This result is more in line with theories that capitalize on the quality of the finally selected representation than with processing models aimed at reaching one single solution as fast and as economically as possible.

Cues↗