1. Semantic representation and storage How do we store what we know about the world?

2. What is semantic memory? People know a lot of stuff. Think of everything you know about cars. It’s more than you think. How is this stuff organized?

3. Semantic Networks

4. Decision Networks

5. What does semantic memory do?

6. Unitary Content Hypothesis Information storage is based on categories. All information about a category is stored in one place, and is accessible by every sensory modality.

7. Evidence for the UCH Fits with our intuitions about the hierarchy of semantic categories. Lots of cognitive effects (priming, recognition, memory) are influence by category-based semantic relationships Certain brain-damaged patients show category- specific deficits, where they are unable to identify objects from particular categories.

8. Multiple Semantics Hypothesis Semantic information is stored by sensory modality rather than category. All information about a given category is strongly linked, but direct access to a given piece of information is only possible through that modality.

9. Evidence for the MSH The rest of the cognitive system organizes its processing based on sensory modality. Why wouldn’t the semantic system? Attention research shows that there is significant priming based on sensory modality. There exist brain-damaged patients with modality-specific deficits of semantic processing.

10. The Sensory-Functional Hypothesis Category-specific deficits are not very fine- grained. You won’t have a deficit for just dogs, but for all living things. Maybe this is due not to category effects, but to how information is being represented. Natural objects - more visual respresentation Man-made objects - more functional representation