Semantic feature-comparison model

Semantic Feature Comparison Model is used "to derive predictions about categorization times in a situation where a subject must rapidly decide whether a test item is a member of a particular target category".. This semantic model explains how humans categorize objects into groups based on their features. When a new item is encountered, its basic features are identified and matched to the group with which those features correspond. The most popular example of this model is the statement “The robin is a bird.” The robin shares common features with all birds, but has its own unique features that differentiate it from all other birds.

History

This model was conceptualized by Edward Smith, Edward Shoben and Lance Rips in 1974 after they derived various observations from semantic verification experiments conducted at the time. Respondents merely had to answer 'true' or 'false' to given sentences. Out of these experiments, they observed that people responded faster when (1) statements were true, (2) nouns were members of smaller categories, (3) items were 'typical' or commonly associated with the category (also called prototypes), and (4) items were primed by a similar item previously given (University of Alaska Anchorage, n.d.). In the latter item, respondents responded faster to the latter statement since the category “bird” was primed. Based on the previous observations, the proponents were able to come up with the Semantic Feature Comparison Model.

Theory

The cognitive approach consists of two concepts: information processing depends on internal representations, and that mental representations undergo transformations. For the first concept, we could describe an object in a number of ways, with drawings, equations, or verbal descriptions, but it is up to the recipient to have a background understanding of the context to which the object is being described in order to fully comprehend the deliverable. The second concept explains how memory can alter the way we perceive representations of something, by determining the sequence in which the information is processed based on previous experiences.

Features

The main features of the model, as discussed by Smith et al. (1974), are the defining features and the characteristic features. Characteristic features refer to basic elements of the category. For example, the 'bird' category includes such characteristic features as 'they have wings,' 'they have feathers,' 'they lay eggs,' etc. Defining features refer to the elements usually found or inherent to specific categories but are not found in the general, overarching category. For example, a robin has red feathers-- all birds have feathers (characteristic), but red feathers are defining to a robin specifically. The model has two stages for decision making. First, all features of the two concepts (bird and robin, in our example) are compared to find out how alike they are. If the decision is that they are very similar or very dissimilar, then a true or false decision can be made. Second, if the characteristics/features are in-between then the focus shifts to the defining features in order to decide if the example possesses enough features of the category. The categorization depends on similarity and not on the size of the category.

References

• University of Alaska Anchorage (n.d.). Cognitive Psychology – Memory Models, Knowledge Representation. Retrieved November 5, 2012 from http://www.math.uaa.alaska.edu/~afkjm/cs405/handouts/psycho.pdf
• Gazzaniga, Michael S., Richard B. Ivry, and G. R. Mangun. "Methods of Cognitive Neuroscience." Cognitive neuroscience: the biology of the mind. Third ed. New York: W.W. Norton, 1998. 111–112. Print.