2. Through the use of serial learning Ebbinghaus determined that much of what we learn is forgotten very shortly after a learning session. Other methods include paired-associate learning and free recall.

3. These basic methods were developed and expanded by incorporating additional tasks, such as the recognition test and the relearning test.

4. The savings score, which is produced by the relearning method, is widely used today.

5. Some investigators have drawn a parallel between the computer and human memory. Computers and human memory have (a) an input or encoding stage, (b) a storage process, and (c) a retrieval process.

6. The Atkinson-Shiffrin model of memory proposes that memories can be processed in different ways. There are three types of memory: sensory, short -term, and long-term.

7. Sensory memory is a very brief (lasting one-half to 1 second) memory for a large array of stimuli.

8. Short-term memory (STM) is more limited in capacity than sensory memory but lasts longer (10 to 20 seconds).

9. With practice or rehearsal, memories may persist even longer and ultimately be transferred to more permanent storage in long-term memory (LTM).

10. Memories may not be retrievable from LTM because they have faded or because of interference by other memories.

11. Proactive interference occurs when old material interferes with the retrieval of material learned more recently. Retroactive interference occurs when recently learned material interferes with the retrieval of material learned earlier.

12. Craik and Lockhart proposed that there may be only one type of memory. The level of processing may determine the permanence of the storage of this memory.

13. Other researchers have proposed more than one type of long-term memory. Four types have been identified: procedural, semantic, episodic, and priming or implicit memory. Each serves to store a different kind of information.

14. The tip-of-the-tongue (TOT) phenomenon has been used to study the network of semantic memories, whereas the study of flashbulb memories has provided information about episodic memory.

15. Research on the retrieval of memories has shown that we scan both STM and LTM to locate an item we wish to recall.

16. Encoding specificity has a great deal to do with the ease with which a memory is retrieved. If the cues that were present when a memory was encoded or stored are not present during retrieval, it is difficult to retrieve that memory.

17. Encoding specificity appears to be at work in situations such as state dependent learning.

18. It has been suggested that memories of childhood sexual abuse may be repressed and recalled during adulthood. Many of these repressed memories appear to have been induced during therapy sessions by suggestions made by the therapist.

19. The number of sessions, distribution of practice, meaningfulness of items, similarity of items, and serial position of items influence human learning.

20. Our memory can be improved by employing a mnemonic device such as imagery. The method of loci and the pegword technique are two popular mnemonic devices. Grouping and coding are two other techniques that can be used as memory aids.

21. Physical trauma may result in a loss of memory known as amnesia. Anterograde amnesia occurs when new information cannot be stored, although old memories remain intact. It can result from damage to the hippocampus. Retrograde amnesia occurs when memories for events occurring before the traumatic event are lost. It may occur when memories are not allowed to consolidate or set.

22. Model systems that contain relatively few neurons are used to isolate the neural circuits and neurotransmitter changes involved in habituation, sensitization, and other types of learning.

23. Increases in acetylcholine (ACh) have also been proposed as a basis for learning. Norepinephrine, serotonin, and dopamine are neurotransmitters that may also be involved in learning and memory.

24. Stimulation of the hippocampus results in the exposure of additional glutamate receptors on the postsynaptic membrane. Thus there is greater sensitivity to glutamate, and the cells may respond for a long time (long-term potentiation).

25. There are significant differences between the brains of rats raised in impoverished environments and those of rats raised in enriched environments.