They fail a spatial working memory task in which they have to remember where food is located in space. The latter is an example of associative memory, not spatial working memory. The frontal lobes are involved in retrieval of episodic memories. Frontal patients have difficulty remembering when they learned a specific fact, compared to normals. However, they are no different from normals in knowing that fact is familiar, i.e. that they learned it in the past.
Memory is more complex than can be expressed in verbal descriptions.
For example we know memory is better for items that are rehearsed more, that are processed meaningfully, that are at the beginning of a list, etc. But we need models to understand how all these factors interact. Models allow us to both express theories and to develop theories. We develop a theory by expressing it as a model and relating the model to the data. Two main types of models in Cognitive Psychology are mathematical models and computer models.