Simultaneous-sequential Paradigm Research Articles

Experimental Studies of the Attention Processing Model in Multiple Object Tracking Task.

(1) Background: Attention is an important cognitive process in daily life. However, limited cognitive resources have been allocated to attention, especially for multiple objects and its mechanism is still unclear. Most of the previous studies have been based on the static attention paradigms with relatively lower ecological validity. Thus, we aimed to explore the attention processing mechanism in a multiple object tracking (MOT) task by using a dynamic attention paradigm. Two experiments were conducted to assess whether there was a multi-focus attention processing model, and whether the processing model changes with the number of target balls. (2) Methods: During the experiments, 33 university students completed MOT combined with the simultaneous-sequential paradigm, with tracking accuracy and reaction time of correct reaction as indicators. (3) Results: (i) When there were two target balls, an obvious bilateral field advantage was apparent. (ii) When there were four target balls, participants' performance was significantly better when stimuli were presented simultaneously than when they were presented sequentially, showing a multi-focus attention processing model. (4) Conclusion: Attention processing is characterized by flexibility, providing strong evidence to support the multi-focus theory.

Ensemble representation for multiple facial expressions: Evidence for a capacity limited perceptual process.

We tested the processing capacity of establishing ensemble representation for multiple facial expressions using the simultaneous-sequential paradigm. Each set consisted of 16 faces conveying a variable amount of happy and angry expressions. Participants judged on a continuous scale the perceived average emotion from each face set (Experiment 1). In the simultaneous condition, the 16 faces were presented concurrently; in the sequential condition, two sets, each containing eight faces, were presented successively. Results showed that judgments varied depending on the number of happy versus angry faces contained in the sets and were sensitive at the single trial level to the perceived mean emotion intensity (based on postexperiment ratings), providing evidence of a genuine mean representation rather than the mere use of a single face or enumeration. Experiments 2 and 3 replicated Experiment 1, but implemented a different response format (binary choices) and added masks following each display, respectively. Importantly, in all three experiments, performance was consistently better in the sequential than in the simultaneous condition, revealing a limited-capacity process. A set of control analyses ruled out the use of enumeration or mere subsampling by the participants to perform the task. Collectively, these results indicate that participants could readily extract mean emotion from multiple faces shown concurrently in a set, but this process is best conceived as being capacity limited.

Information processing capacity in psychopathy: Effects of anomalous attention.

Hamilton and colleagues (2015) recently proposed that an integrative deficit in psychopathy restricts simultaneous processing, thereby leaving fewer resources available for information encoding, narrowing the scope of attention, and undermining associative processing. The current study evaluated this parallel processing deficit proposal using the Simultaneous-Sequential paradigm. This investigation marks the first a priori test of the Hamilton et al.'s theoretical framework. We predicted that psychopathy would be associated with inferior performance (as indexed by lower accuracy and longer response time) on trials requiring simultaneous processing of visual information relative to trials necessitating sequential processing. Results were consistent with these predictions, supporting the proposal that psychopathy is characterized by a reduced capacity to process multicomponent perceptual information concurrently. We discuss the potential implications of impaired simultaneous processing for the conceptualization of the psychopathic deficit. (PsycINFO Database Record

Search for Capacity-Limited and Super-Capacity Search.

The present study investigated capacity limitations of visual search. In a series of experiments, participants searched for a singleton target among homogenous distractors, a conjunction target defined by combination of two features, or a feature target among heterogeneous distractors. Using the simultaneous-sequential paradigm, I found that singleton search proceeded in a capacity-unlimited manner. By contrast, the performance of the conjunction search was found to depend on a capacity-limited process. For feature searches, the performance of searching for a specific color was not affected by how the stimuli were presented, while the orientation search performance was enhanced as the number of distractors simultaneously presented with the target increased. These results imply that distinct colors are individually coded, whereas multiple orientations are encoded as an ensemble in a structured way. Taken together, the present study clarifies which type of search process are capacity-limited and reveals how this limit can be overcome.

The Identity-Location Binding Problem

The binding problem is fundamental to visual perception. It is the problem of associating an object's visual properties with itself and not with some other object. The problem is made particular difficult because different properties of an object, such as its color, shape, size, and motion, are often processed independently, sometimes in different cortical areas. The results of these separate analyses have to be combined before the object can be seen as a single coherent entity as opposed to a collection of unconnected features. Visual bindings are typically initiated and updated in a serial fashion, one object at a time. Here, we show that one type of binding, location-identity bindings, can be updated in parallel. We do this by using two complementary techniques, the simultaneous-sequential paradigm and systems factorial technology. These techniques make different assumptions and rely on different behavioral measures, yet both came to the same conclusion.

Your own face is no more precious than others': Evidence from the simultaneous--sequential paradigm.

In the present study, we tested the dominant notion that the processing of familiar faces takes place in an automatic, capacity-unlimited manner. To do so, we had participants perform the task of detecting their own face among others' nonfamiliar faces. Importantly, either all of the search stimuli were presented simultaneously or two different subsets of the stimuli were presented sequentially. The results showed that the search performance benefited from sequential presentation, indicating that detecting one's own face depends on a capacity-limited process. A similar pattern of results was found when participants searched for someone else's face, although there was a decline in the overall performance. These findings suggest that the processes of detecting familiar and unfamiliar faces suffer from the capacity limit of visual perception to similar extents, challenging the notion of the automaticity of familiar-face processing.

Part-whole information assists in topological × topological but not in orientation × orientation conjunction searches.

Visual search is a routine task used in everyday life and is an important field of research in cognitive psychology. In laboratory settings, it has been shown that search for a target defined by a unique conjunction of two colours is more efficient if one colour surrounds the other (a part-whole search) compared to when no such hierarchical structural relationship exists (a part-part search; Wolfe et al. in Perception & Psychophysics, 55, 537, 1994). A similar result has been shown to hold for size × size conjunction searches (Bilsky & Wolfe in Perception & Psychophysics, 57, 749, 1995). We show that this result also holds for topology × topology conjunction searches (where the stimuli are either hollow or filled), but not for orientation × orientation conjunction searches. We use the simultaneous-sequential paradigm to investigate a possible reason for the inefficiency of part-whole orientation search compared with the efficiency of part-whole searches of other features. We argue that two different attribute values from the same dimension can be processed independently, without interfering with each other for colour, size, and topology, but not for orientation. Because it is obviously more efficient to process a conjunction stimulus when both components of the conjunction can be processed without mutual interference, it follows that colour × colour, size × size, and topological × topology part-whole conjunction searches are likely to be more efficient than orientation × orientation part-whole conjunction searches.

The Identity-Location Binding Problem.

The binding problem is fundamental to visual perception. It is the problem of associating an object's visual properties with itself and not with some other object. The problem is made particular difficult because different properties of an object, such as its color, shape, size, and motion, are often processed independently, sometimes in different cortical areas. The results of these separate analyses have to be combined before the object can be seen as a single coherent entity as opposed to a collection of unconnected features. Visual bindings are typically initiated and updated in a serial fashion, one object at a time. Here, we show that one type of binding, location-identity bindings, can be updated in parallel. We do this by using two complementary techniques, the simultaneous-sequential paradigm and systems factorial technology. These techniques make different assumptions and rely on different behavioral measures, yet both came to the same conclusion.

Evidence of fixed capacity in visual object categorization

How is visual object perception limited by divided attention? Whereas some theories have proposed that it is not limited at all (unlimited capacity), others have proposed that divided attention introduces restrictive capacity limitations or serial processing (fixed capacity). We addressed this question using a task in which observers searched for instances of particular object categories, such as a moose or squirrel. We applied an extended simultaneous-sequential paradigm to test the fixed-capacity and unlimited-capacity models (Experiment 1). The results were consistent with fixed capacity and rejected unlimited capacity. We ascertained that these results were due to attention, and not to sensory interactions such as crowding, by repeating the experiment using a cuing paradigm with physically identical displays (Experiment 2). The results from both experiments were consistent with theories of object perception that have fixed capacity, and they rejected theories with unlimited capacity. Both serial and parallel models with fixed capacity remain viable alternatives.

Extending the simultaneous-sequential paradigm to measure perceptual capacity for features and words.

In perception, divided attention refers to conditions in which multiple stimuli are relevant to an observer. To measure the effect of divided attention in terms of perceptual capacity, we introduce an extension of the simultaneous-sequential paradigm. The extension makes predictions for fixed-capacity models as well as for unlimited-capacity models. We apply this paradigm to two example tasks, contrast discrimination and word categorization, and find dramatically different effects of divided attention. Contrast discrimination has unlimited capacity, consistent with independent, parallel processing. Word categorization has a nearly fixed capacity, consistent with either serial processing or fixed-capacity, parallel processing. We argue that these measures of perceptual capacity rely on relatively few assumptions compared to most alternative measures.

Distinguishing between parallel and serial accounts of multiple object tracking

Humans can track multiple moving objects. Is this accomplished by attending to all the objects at the same time or do we attend to each object in turn? We addressed this question using a novel application of the classic simultaneous-sequential paradigm. We considered a display in which objects moved for only part of the time. In one condition, the objects moved sequentially, whereas in the other condition they all moved and paused simultaneously. A parallel model would predict that the targets are tracked independently, so the tracking of one target should not be influenced by the movement of another target. Thus, one would expect equal performance in the two conditions. Conversely, a simple serial account of object tracking would predict that an observer's accuracy should be greater in the sequential condition because in that condition, at any one time, fewer targets are moving and thus need to be attended. In fact, in our experiments we observed performance in the simultaneous condition to be equal to or greater than the performance in the sequential condition. This occurred regardless of the number of targets or how the targets were positioned in the visual field. These results are more directly in line with a parallel account of multiple object tracking.

Distinguishing serial and parallel models using variations of the simultaneous-sequential paradigm

Distinguishing serial and parallel models using variations of the simultaneous-sequential paradigm