What Is a Federated Search?

Combined search (conjunction search) refers to the specific combination of features that people look for when performing a visual search of their surroundings, for example. The only difference between T and L is the different integration of the lines, not the distinctive characteristics of the two. ^[1]

Feature integration theory (feature-integration theory) is a theory of cognitive psychology. It was proposed by Treisman and Gelade in 1980 and tried to use the shortcomings of the variable focal length model without explaining the processing mechanism of visual concentration attention. Feature integration theory makes up for this shortcoming. This theory is also a theory of attention involving automatic processing. They distinguish between objects and features, treating features as a specific value of a certain dimension, and objects as a combination of some features. They believe that the characteristics are analyzed by a functionally independent subsystem of perception. This processing is performed in parallel, and the identification of objects requires concentrated attention and participation, which is the result of a series of processing; concentrated attention The effect is similar to "glue", allowing some features to be combined into a single object. Treisman believes that the visual processing process is divided into two stages, and feature integration occurs in the later stages of visual processing, which is a non-automated, sequential processing, namely:

Feature registration phase. It is equivalent to the pre-attention stage. At this time, people hardly need to work or even realize that it does not happen. Pre-attention processing can help people perform a directional search of the surrounding environment. The vision system extracts features from the light stimulation mode, which is a parallel and automated processing process. Treisman hypothesized that in the early stages of vision, only independent features can be detected, including color, size, orientation, contrast, tilt, curvature, and line endpoints, and may also include differences in distance between motion and distance. These features are in a free-floating state (unconstrained by the object they belong to, their position is subjectively uncertain). The perceptual system encodes the features of each dimension independently. The psychological representation of these individual features is called a feature map. However, the pre-attention stage cannot detect the relationship between features.

Feature integration stage (object perception stage). Perceptual systems correlate correctly separated features (characteristic representations) to form a representation of an object. At this stage, it is required to locate the feature, that is, to determine where the boundary position of the feature is. This is called a map of locations. The location information of the processing features needs concentrated attention. Concentrated attention is like glue, integrating primitive, separate features into a single object. This series of processing is slower than the former. Due to the need for effort, when the attention is overloaded or people are distracted, especially when the demand for attention is high, the characteristics of the stimulus will be improperly combined, causing an illusion.