Integration of local features as a function of global goodness and spacing

Abstract

In two experiments, the accuracy with which subjects detected a conjunction of features was examined as a function of the spacing between items and the goodness of the axis along which they were located. In each array, two items were arranged along a vertical, a horizontal, or a diagonal axis. Based on the well-established oblique effect, the vertical and horizontal axes were considered to be good global patterns and the diagonals were considered to be poor. In Experiment I, the two items in an array could be two horizontal lines, two vertical lines, a vertical and a horizontal line, or a plus sign with one of the single lines. In Experiment 2, a positiveand a negative-diagonal line were used as the individual features, and an "X" was used as the conjunction. The results from Experiment 1 indicated that global goodness influenced only the rate of illusory conjunctions, and not of feature errors. lllusory conjunctions of vertical and horizontal line segments were more likely to occur in vertical and horizontal arrangements. The results from Experiment 2 revealed a reversal of the effect of global goodness on the rate of illusory conjunctions: Illusory conjunctions of negative-and positive-diagonal line segments were more likely to occur in diagonal arrangements. The results of both experiments taken together showed the existence of an important and new factor that influences the likelihood that features of shape will be conjoined: the ease with which line segments conjoin when they are translated along their extent toward each other. In both experiments, greater spacing between items produced more feature-identification errors and fewer feature-integration errors than did less spacing.

Role of eccentricity and size in the global precedence effect.

“…The main results are demonstrated in Figure Consistent with earlier findings (Boles, 1984;Lasaga & Hecht, 1991;Luna, Merino, & Marcos-Ruiz, 1990;Navon, 1977Navon, , 1983Navon, , 1991 Reaction time is usually used as independent variable in the studies on visual perception. In a RT task subjects are usually required to respond as rapidly and as correctly as possible.…”

“…Navon (1983) suggested that global precedence is a claim about the order of processing of the global and local features. However, temporal precedence of one level over the other does not determine if this precedence is simply because of earlier availability of information at that level or if it is the result of using the output of one level to process the information at the level completed later (Lasaga & Hecht, 1991). Studies up to now have not provided strong evidence on the inevitability of the processing of either the global or local level as the necessary input for the processing of the other level.…”

“…However, it seems more probable that response competition has its origin in 'global precedence' rather than being its source (Hughes, 1984). Meanwhile, it should be considered that the temporal precedence or asymmetric interference does not determine if these effects are simply because of the earlier availability of information at the superior level or if that information is partly or fully used as an output to process information at the level completed later (Lasaga & Hecht, 1991). Task requirement will not be experimentally investigated in this chapter but it is explained as an issue that may effect experimental results.…”

“…According to this study a global configuration composed of a large number of local elements looks better than the one that consists of few local components. Lasaga and Hecht (1991) differentiated between spacing (i.e., density/sparsity) and pattern goodness. According to these workers goodness of a shape is similar to the reflection of the quality of cohesion, but density reflects the intensity or strength of the cohesion.…”

The CODE theory of visual attention: An integration of space-based and object-based attention.

“…Nevertheless, the CTVA fits are encouraging. They suggest that the model could be extended to deal with the other cases in the literature (e.g., Chastain, 1982;Ivry & Prinzmetal, 1991;Lasaga & Hecht, 1991;Prinzmetal & Keysar, 1989;Prinzmetal & Mills-Wright, 1984;Prinzmetal, Treiman, & Rho, 1986;Wolford & Shum, 1980). The model did not deal with the initial digit-report task or the shift of attention from the digits to the target in any of the ex-71 was able to improve the fit and capture the quantitative difference between the large and small spotlight conditions by allowing the standard deviation of the feature distributions to vary between spotlight conditions, following Ashby et al (1996) who fitted the same data by allowing larger variance in the large spotlight condition.…”