In theory of
cognition, visual search is a type of perceptual task requiring attention. Visual search involves an active scan of the visual environment for a particular object or feature (the target) among other objects or features (the distracters). Visual search can take place either with or without eye movements. Common examples include trying to locate a certain brand of cereal at the grocery store or a friend in a crowd (e.g. Where's Waldo?). The scientific study of visual search typically makes use of simple, well-defined search items such as oriented bars or colored letters.
The efficiency of visual search depends on the number and type of distracters that may be present. Search tends to be more efficient when the target is very different from the distracters. The number of targets and distractors in a given visual array is called the display size. The display size effect is the degree to which task performance (
Reaction timeand/or accuracy) depends on the display size. The magnitude of the display size effect can vary greatly, from effectively zero (e.g., in searches for a red target among green distracters, called a "feature search") to a large effect (e.g., in searches for a red X among green Xs and red Os, called a "conjunction search"). Search tasks with a small display size effect are referred to as "efficient;" search tasks showing a large display size effect are termed "inefficient."
Types of search
Feature Search is the process of searching for targets defined by a unique visual feature, such as color, size, orientation or shape. Feature searches are typically efficient. For instance, an O is rapidly found among Xs, and a red target is rapidly found if all the distracters are black (see illustrations).
Conjunction Search occurs when a target stimulus is defined not by any single visual feature, but by a combination of two or more features. An example is search for an orange square among blue squares and orange triangles (see illustration): neither the single feature "orange" nor the feature "square" is sufficient in isolation to uniquely specify the search target.
Conjunction searches are typically inefficient, with the time to complete the search task increasing linearly with the number of distractors. This behavior is as if the subject were forced to examine each item in the search array one at a time before deciding whether or not it was the search target, leading to the term "serial search".
Theories of visual search
Feature integration theory
Attentional engagement theory
Guided search theory
*Wolfe, J M (1998). Visual Search. In H. Pashler (Ed.), "Attention," East Sussex, UK: Psychology Press. [http://search.bwh.harvard.edu/pdf/THE%20REVIEW.pdf Fulltext]
*Theeuwes, J. (1992). Perceptual selectivity for color and form. "Perception & Psychophysics, 51," 599-606. [http://www.cs.vu.nl/~cogsci/cogpsy/theeuwes/P%26P_1992_Theeuwes.pdf Fulltext]
*Treisman, A., & Gelade, G., 1980. A feature integration theory of attention. "Cognitive Psychology, 12," 97-136.
*Verghese, P. (2001). Visual search and attention: A signal detection theory approach. "Neuron, 31," 523-535(13).
Wikimedia Foundation. 2010.
Look at other dictionaries:
Visual search engine — A Visual Search Engine is a search engine designed to search for information on the World Wide Web through the input of an image or a search engine with a visual display of the search results. Information may consist of web pages, locations,… … Wikipedia
Visual inspection — is a common method of quality control, data acquisition, and data analysis. Visual Inspection, used in maintenance of facilities, mean inspection of equipment and structures using either or all of human senses such as vision, hearing, touch and… … Wikipedia
Visual memory — Close up of the human eye, where vision begins. Visual memory describes the relationship between perceptual processing and the encoding, storage and retrieval of the resulting neural representations. Visual memory occurs over a broad time range… … Wikipedia
Visual modularity — In cognitive neuroscience, visual modularity is an organizational concept concerning how vision works. The way in which the primate visual system operates is currently under intense scientific scrutiny. One dominant thesis is that different… … Wikipedia
Visual comparison — A visual comparison is to compare two or more things by eye. This might be done by placing them side by side; by overlaying them; by alternating an image or by presenting each image to a separate eye.Such comparisons are the first stage in a… … Wikipedia
Visual descriptors — describe the visual features of the contents in images or videos. They describe elementary characteristics such as the shape, the color, the texture or the motion, among others.IntroductionAs a result of the new communication technologies and the … Wikipedia
Visual networking — refers to an emerging class of user applications that combine digital video and social networking capabilities. It is based upon the premise that visual literacy, the ability to interpret, negotiate and make meaning from information presented in… … Wikipedia
Visual Basic for Applications — (VBA) Paradigm(s) Multi paradigm Appeared in 1993 Developer Microsoft … Wikipedia
Visual Basic Scripting Edition — (обычно просто VBScript) скриптовый язык программирования, интерпретируемый компонентом Windows Script Host. Он широко используется при создании скриптов в операционных системах семейства Microsoft Windows. VBScript был создан компанией Microsoft … Википедия
search — consists of looking for or seeking out that which is otherwise concealed from view. People v. Carlson, Colo., 677 P.2d 310, 316. An examination of a person s house or other buildings or premises, or of his person, or of his vehicle, aircraft, etc … Black's law dictionary