Summary and Conclusion

Summary

The present study was concerned with the retrieval of semantic information. Retrieving semantic information is a fundamental process in almost any kind of cognitive behavior. The Introduction presented the main experimental para­digms and results found in the literature on semantic memory as well as an outline of the most important models.

The tasks that generally were used are simple verification tasks. In one type of tasks subjects are required to judge whether a relation exists between two concepts. The concept s are presented in a sentence, e.g., a canary is a bird or a canary is a sparrow. The sentences have to be judged as true or false. In another type of tasks two concepts are presented, e.g.,oak beech or oak sparrow, and t he subject has to judge whe ther both concepts are exemplars of a prespecified category, e.g., tree. The concepts have to be judged as same or different with respect to t he prespeci fied categories.

The main results of such studies can be summarized as follows. The reaction time (RT) is a function of the semantic similarity between concepts. The RT for j udgments on true or same items is shorter the more similar the words are, e.g., the RT for a canary is a bird is shorter than the RT for a canary is an animal. The RT for judgments on false or different items is longer the more similar the words are, e.g., t he RT for a canary is a fish is longer than the RT for a canary is a flower. These phenomena are called semantic distance effects for same and different judgments, respectively. Furthermore, it is observed from the results presented in the lite rature that the RT for true (same) items is shorter than the RT for false (different) items, e.g., the RT for a canary is a bird is shorter than the RT for a canary is a fish. This phenomenon is termed the same/different effect.

Chapter 2 discussed the statistical analysis of t he RT data, focussing specifically on the use of medians.

The main body of this study consists of three parts.