Overview of Long-Term Memory

1. Overview of Long-Term Memory laura leventhal

2. Reference • Chapter 14

3. Learning and LTM • The major task of learning new material is to integrate it into the existing structure of information that is already in LTM. • Rehearsal is useful to retaining information in STM and Working Memory • LTM requires rehearsal and integration • Integrated information in LTM is KNOWLEDGE

4. Features of LTM • LTM is permanent memory (as opposed to STM or working memory) • LTM has essentially infinite capacity. It is an open question whether people ever truly forget information that is stored in LTM. • LTM has slower access compared to STM • 1/10th of a second vs. 70 ms

5. Features of LTM (2) • Information gets into LTM from STM, via rehearsal Getting information out of LTM is called retrieval. Information can be in two ways, recall or recognition. • In recall, information to be retrieved from LTM must first be found and then recalled. In recognition, an informational cue is provided and the information retrieved is matched against the presented cue. • Designer Lesson • Generally recall is more difficult than recognition. You will probably remember that in our discussion of interaction styles, we mentioned that menus may be easier for novices to use as compared to command line interactions. Why - with menus, all options are presented explicitly, so selecting a menu option involves recognition. When using command line interactions, generating a command involves recall.

6. Information can be accessed in different ways • LTM stores different sorts of information • Information can be retrieved or accessed in different ways • For example • people have excellent recognition memory ("I always remember a face", deja vu) -but may do less with at retrieving linguistic label (name)

7. Types of knowledge in LTM • Information in LTM is organized into two types of knowledge: declarative knowledge and procedural knowledge. • Declarative knowledge or knowledge of facts indicates "knowing what". An example of declarative knowledge is knowing the answer to the following question "what is the capital of Ohio?" Declarative knowledge is easy to communicate • Procedural knowledge is knowing how to do". In general, procedural knowledge may be more difficult to communicate. • Designer LessonIn some of our recent work, we have used dual presentations of text and visuals to convey procedural information. In particular, virtual reality presentations seem to be quite effective in presenting this type of information.

8. Representation of Knowledge • Knowledge is organized 1] hierarchically (represents categories), 2] temporally (represents sequences) and in 3] networks (represents complex connections). • Both the information and its organization changes over time. We observe that the organization of information in LTM supports our memories of episodic: events to experiences in temporal order. • An expert has developed a complex, multi-level body of knowledge in their domain of expertise, stored in LTM.

9. Representation of Knowledge (2) • Some knowledge is semantic or about meaning. Semantic knowledge is knowledge of general concepts, independent of a specific situations. For example, an expert programmer understands the concept of array regardless of the programming language. • Some knowledge is syntactic or about surface structure. Syntactic knowledge is also stored in LTM, but it is more detailed than semantic knowledge and is less (cognitively) structured. Knowing the format of the C++ while structure is an example of syntactic knowledge. Syntactic knowledge is more easily forgotten than semantic knowledge. • Semantic knowledge is acquired through demanding and meaningful problem-solving. • Syntactic knowledge is acquired by rote. The acquisition of new syntactic information may interfere with previously-learned syntactic knowledge or vice versa. Hence, programmers often have much difficulty learning a second programming language. • There are vast individual differences in the quality and capabilities of building informational structures in LTM. Also children and adults differ. Adults have an existing informational structure. Their challenge is to integrate new concepts into the existing structure. .Children on the other hand are building their DB so much of what they do is concept learning and formation. • Designer Lesson Even within a narrow group, ability to integrate new concepts will vary tremendously.

10. Learning - construction of knowledge • Learning is a key focus of cognitive psychology and has been the subject of many studies and experiments. • Here is a short summary about learning. • Learning is the process of building knowledge; this may involve the formation of concepts. • Learning is complex. • Learners are not passive absorbers of information. • Learning involves the integration of new information and experiences with our existing structures. • What we learn may be wrong. • We learn by rehearsal, doing, vivid experiences and through analogies.

11. Learning - Designer Lessons • Research in HCI has suggested that people learn to use computer systems most effectively if learning is active.. • Consider having users engage in actual interface tasks not long bouts of manual reading. Active learning may also be enhanced if user makes errors and receives useful feedback. • Set goals where action sequence is obvious. • Use analogies

12. Skill Acquisition • Some CHI activities involve skill acquisition or use of skill rather than complex knowledge. There are many “laws” of human factors that one can use in design. These generally apply to sensory-motor skills rather than knowledge. • For example, the power law of skill acquisition suggests that our improvement is fast at first then much slower. When you learn to do something, like use a mouse, you improve quickly at first.. Subsequent improvements take longer. The more that you practice, the faster that you get though. • The power law states that task time on the nth trialTn = T1n-.4 where n is a constant for task