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V Modigliani

Publications and source records attributed to V Modigliani.

8 recordsLinked to original sources
PubMed2001

Attention and size in a global/local task.

Two-letter stimuli, consisting of one small letter inside a much larger one (in Experiments 1A, 1B, and 2) or inside a "blob" (in Experiment 3), were used to examine the role of size difference in global/local tasks. The small letter was placed at locations that avoided contour interactions. The results showed no identity interference, in that the specific identity of the large letter did not differentially affect identification of the small one. However, there was evidence of global advantage, in that the presence of a large letter hindered identification of the small one. The magnitude of the global advantage effect, as measured by the difference in performance between the small-single and small-embedded conditions, was largest (about 200 ms reaction time (RT) difference) when the large letters were the same as the small ones, lower (a 63 ms difference in Experiment IB, and 89 ms in Experiment 2) when the large letters were unrelated to the small ones, and lowest (a 25 ms difference) when the large stimuli were blobs. It is proposed that the amount of interference depends on the overlap between the features of the large stimuli, as a set, and those of the small ones, also as a set.

Adult↗
PubMed1998

Encoding features of complex and unfamiliar objects.

This study explored the acquisition of features from complex, unfamiliar objects. It tested the principle of top-down encoding, which predicts that the time needed to detect a difference between stimuli that differ in only one critical feature increases and recognition decreases as the level of that feature decreases. Results of Experiment 1 supported these hypotheses. Experiment 2 eliminated retroactive interference as an explanation for the results of Experiment 1. Experiment 3 showed that top-down encoding can be altered by explicit instructions to attend the relevant feature. It also showed that discriminability due to size was not a factor in Experiments 1-3. Experiment 4 showed that the top-down principle can account for how people encode features as a function of task demands. Overall, the results indicate that under normal attention conditions, the probability of encoding a feature decreases with its structural level. However, this tendency can be altered by explicit instructions or other factors.

Adult↗
PubMed1996

Inattention and the perception of visual feature conjunctions.

Visual processing of objects in the absence of focused attention appears to be limited. We varied the degree of attention, or visual processing, that observers paid to objects using an instruction set manipulation. In 2 experiments, subjects performed tasks that required superficial or detailed visual analysis of the objects involved. In subsequent recognition tests, information about conjunctions of shape and internal color/texture pattern was limited when only superficial visual analysis was required to encode the object. This implies that the degree of visual processing, during object encoding affects the likelihood that feature conjunctions are incorporated into the visual representation of these objects.

Adult↗
PubMed1992

Lateral masking as a determinant of global dominance.

The term compound letter refers to a large (global) letter made up of small (local) letters. Reaction time to identify local letters is longer when local and global letters are different than when they are the same (the global dominance effect). The possible contribution of lateral masking to this effect was investigated. Lateral masking denotes reduced probability of identifying a stimulus when it is closely surrounded by other stimuli (as is the case for the local items in a compound stimulus). Three experiments were conducted in which the dependent measure was percentage of correct responses, rather than reaction time. In experiment 1 compound letters were used; accuracy of performance yielded evidence of global dominance such as obtained with reaction time measures. In experiments 2 and 3 the strength of lateral masking in geometrical forms was varied by varying the density of their component items. In agreement with earlier suggestions based on indirect evidence, the results directly implicated lateral masking as an important determinant of global dominance. However, lateral masking could not account fully for the experimental outcome. Factors beyond lateral masking, such as global precedence in the processing sequence or inhibitory interactions among low and high spatial-frequency components of the compound images are required in order to provide a comprehensive account of global dominance effects.

Cognition↗
PubMed1983

Stimulus generalization and the peak shift with movement stimuli.

Stimulus generalization is suggested as an alternative method for examination of the "novelty" problem in motor learning. These experiments demonstrated that stimulus generalization occurs using simple movements as stimuli. The phenomenon of the "peak shift" in post-discrimination generalization gradients was also examined. The first experiment demonstrated that a peak shift occurred using linear movements as stimuli and that the magnitude of the peak shift increased as the difference between the training stimuli decreased. The second experiment showed similar results when the stimuli consisted of a range of movements rather than single movement length. The final experiment provided evidence that perception of movement length is influenced by the magnitude of an immediately preceding movement. The relevance of these studies to current motor-learning theory is discussed.

Journal Article↗