Object-based visual selective attention and perceptual organization

Abstract

Wereport the results offour experiments that were conducted to examine both the representations that provide candidate entities available for object-based attentional selection and the influence of bottomup factors (i.e., geometric and surface characteristics of objects) and top-down factors (i.e. context and expectancies) on the selection process, Subjects performed the same task in each of the experiments. They were asked to determine whether two target properties, a bent end and an open end of a wrench, appeared in a brief display of two wrenches. In each experiment, the target properties could occur on a single wrench or one property could occur on each of two wrenches. The question of central interest was whether a same-object effect (faster and/or more accurate performance when the target properties appeared on one vs. two wrenches) would be observed in different experimental conditions, Several interesting results were obtained. First, depending on the geometric (i.e., concave discontinuities on object contours) and surface characteristics (i.e., homogeneous regions of color and texture) of the stimuli, attention was preferentially directed to one of three representational levels, as indicated by the presence or absence of the same-object effect. Second, although geometric and surface characteristics defmed the candidate objects available for attentional selection, top-down factors were quite influential in determining which representational level would be selected, Third, the results suggest that uniform connectedness plays an important role in defining the entities available for attention selection. These results are discussed in terms of the marmer in which attention selects objects in the visual environment.

Attentional selection of complex objects: Joint effects of surface uniformity and part structure

“…The present results replicated previous studies demonstrating that object-based attention only selects objects with uniform surface features (Matsukura & Vecera, 2006;Watson & Kramer, 1999). Having replicated this nonuniformity effect, we next asked if the alignment of part structure and surface cues allows object-based attention to select nonuniform objects.…”

“…We next replicated Watson and Kramer's (1999) absence of an object-based effect with multiple-region objects. Observers viewed displays containing two multiple-region objects, each containing two colors that met halfway through the object.…”

“…We then created multipart objects in which the surface of an outline object was composed of either one color or two different colors; for two-color objects, we manipulated whether the color border coincided with the part boundary or appeared off the part boundary. The color of the object's Time contours was considered a surface characteristic, consistent with previous research (Watson & Kramer, 1999). There were two possible outcomes from the latter experiments.…”

Reinstating object-based attention under positional certainty: The importance of subjective parsing

“…Past research has shown that the manifestation of object effects is influenced by a number of factors, including the quality of the object representation and the participants' subjective organization of a stimulus pattern (Avrahami, 1999;Chen, 1998;Watson & Kramer, 1999). For example, response latencies to a target differ as a function of whether the stimulus pattern is perceived as being made of one object or two objects (Chen, 1998).…”

Spatial attention facilitates selection of illusory objects: Evidence from event-related brain potentials

“…In support of such object-based selection are findings that (1) dividing attention between stimulus elements within the same object is generally more efficient than dividing attention between separate objects (e.g. Duncan 1984;Watson et al 1999;Rodriguez et al 2002) and (2) paying attention to one part of an object results in facilitated processing of stimuli in other parts of the object (Egly et al 1994;Abrams et al 2000;Lamy et al 2002).…”