Chapter 11 – Comparative Cognition 1: Memory Mechanisms

1. Chapter 11 – Comparative Cognition 1: Memory Mechanisms • Outline • What is Comparative Cognition • Animal Memory Paradigms • Working and Reference Memory • Delayed Matching to Sample • Spatial Memory in mazes • Memory Mechanisms • Retrospective and Prospective Coding • Forgetting • Proactive and Retroactive Interference • Retrograde Amnesia • Directed Forgetting

2. Chapter 11 - Animal Cognition 1: Memory Mechanisms • What is Comparative Cognition? • Zentall (1993) • Animal Cognition is often best understood by explaining what it is not. • Learned behavior that is left after simpler associative-learning explanations have been ruled out

3. We have already discussed an example of a cognitive experiment • Identity learning (Sameness) • Train (MTS) • RR+G- • GR-G+ • Test • B B+Y- • Y B-Y+ • Notice the test involves novel stimuli • This is often an important test in cognitive studies • It makes it difficult to explain performance in test based on S-R –O relationships. • There is no RF history of picking Blue following Blue • Seems more likely performance is the result of an understanding of “sameness” • A cognitive rule • Pick the thing that looks the same.

4. What is Comparative Cognition? Continued • Domjan • Theoretical constructs and models used to explain aspects of behavior that cannot be readily characterized in terms of simple S-R or reflex mechanisms. • Key feature • Always adopt the simplest possible explanation

5. What is Comparative Cognition? Continued • Must carefully avoid anthropomorphism • Morgan’s Canon • In no case may we interpret an action as the outcome of a higher psychical faculty, if it can be interpreted as the outcome of the exercise of one that stands lower in the psychological scale. • At first the allure is weak; there is a vague yearning and a mild agitation. Ultimately, the strength of desire grows irresistible; its head turns sharply and it skitters across the uneven floor to caress the objects of its affection with consummate rapture • Coin drawn to a magnet • There are more parsimonious explanations for this behavior • Clever Hans

6. What is Comparative Cognition? Continued • Often involves models of mental activity • The internal clock (chapter 12) • A model for how a biological clock might work • Mental Representations • What is the nature of a memory? • It is not just a snap shot. • It is some how changed to a neural code • What is the nature of that code?

7. Animal Memory Paradigms • What is the difference between learning and memory? • The main difference is how we study each. • Study Learning • We vary aspects of acquisition • Hold retention interval and retrieval variables constant • Study Memory • Hold acquisition constant • Vary retention intervals or variables related to retrieval

9. Types of memory • Short term memory • the phone number for pizza place • Long term memory • Episodic • Picture yourself there (the episode) • What did you have for dinner last night? • What were you doing when you heard about the World Trade Center? • Flash bulb • Semantic • Facts about the world • Who was the first president? • What year were you born? • Procedural • How to do things • ride a bike, drive, swim • sports • musical instruments • write

10. Explicit (declarative) • Knowing that you know (conscious awareness) • Episodic is clearly declarative • the person is clearly aware of learning they experienced. • They have a conscious memory for it. • Semantic is as well • You know that-you-know the year you were born • Clive Wearing had no episodic memory at all • Still knew he had a wife and kids • No memory of spending time with them

11. Implicit (nondeclarative or procedural) • This is learning that you are not consciously aware of. • illustrated by priming experiments • Also H.M. • Mirror drawing task • Also Clive Wearing • Piano • Much of the Pavlovian and Instrumental research we have discussed would fall under procedural • We will discuss animal models of Episodic memory in Chapter 12

12. Working Memory and Reference Memory • another distinction that has received a lot of research interest in comparative cognition •  Reference Memory • Long-term retention of information necessary for the successful use of incoming and recently acquired information • The rules of the game • Working Memory • Short-term information • What did I just do? • Cooking • General recipe • rules for making the dish • Keep track of where you are • What have I already done

13. Walter Hunter (1913). • Rats, dogs, and raccoons. • Light indicates which of three compartments are baited. • animal is confined in start area. • Turn light on; then off to indicate which compartment was correct • They are not allowed to choose for various lengths of time. • Rats - 10 seconds. • Racoons – 25 seconds • Dogs – 5 minutes. • Reference Memory? • Working Memory? • Problem with the study

14. Matching-to sample • Simultaneous • Delayed • Why is this technique better than Hunter’s? • Eliminates behavioral explanation for retention • Face where you intend to go. • Animal has no way of knowing which key will be correct • Left vs. right = 50%

15. What affects an animals memory in a DMTS experiment? • 1) nature of the sample stimulus affects DMTS performance • Lines and shapes • Colors

16. 2. Sample Duration? • Grant (1976) • DMTS • 4 colors R,G,B,Y • Each trial begins with white center key • Warning stimulus • Peck  turns to sample (i.e., Red) • Stays on for different durations • 1,4,8, or 14 s • Test with Delays (retention intervals) • 0, 20, 40, or 60

17. Results (Figure 11.2) trace-decay hypothesis (Roberts & Grant, 1976). A simple idea, but clearly too simple.

18. 3) Similarity between training and testing conditions • Instruction hypothesis (Zentall) • What happens if animals are trained with a particular delay and tested with others? • Sargisson and White (2001). • Train with 0, 2, 4, or 6 s delays. • Test with 0, 2, 4, 6, 8, and 10 s delays.

19. Figure 11.3 0 – normal forget curve 2 – forget curve does not start until 4 s 4 – forget curve does not start until 6 s 6 – no forget curve.  What does this say about forget curves? Not just trace-decay Similarity between training and testing conditions are important

20. Spatial memory in mazesSpatial memory in mazes Spatial memory in mazes Morris Water Maze

21. Train in a room with external cues • Door • Pictures • Light gradients • Platform always in the same location • Release from 4 different locations • Randomly • North, South, East, West • Test? • Escape latency (figure 11.4) • Probe trials • Path analysis.

22. Probe trial mouse

24. Spatial memory in the Radial arm maze • Olton and Samuelson (1976) • Food at end of each arm • Or a subset of arms • Reference Memory? • Working Memory?

25. You-tube vids of 8 arm maze • Normal mouse • Knockout mouse with memory probs

26. How do the rats behave in radial arm maze? • Not a set sequence • No strategy • No odor cues • They can handle long delays • Let them choose four arms – four hours later they choose the other 4 • Even after 24 hours they are performing above chance

27. Retrospective and Prospective Coding • How do the rats keep track of the arms of the maze? • Retrospective • keep track of where they have been • Prospective • keep track of where they are going • Cook, Brown, and Riley (1985) • 12 arm maze • Let rats choose 1, 2, 3, 4, 5, 6, 7, 8 , 9, 10, 11 arms. • Remove the rat for 15 minutes • Put them back in and complete the maze.

28. retrospective memory • memory load would start out low • increases with arms visited • having a heavy memory load, should lead to more mistakes • predicts few errors after 1 choice • many errors after 11 choices. • prospective memory • Memory load starts out high • Have 11 arms still in memory • Decreases with arms visited • having a heavy memory load, should lead to more mistakes • Predicts many errors after 1 choice • Few errors after 11 choices

30. These predictions are in direct contradiction to one another.  • What do rats do? • People?

31. Forgetting • Why does memory sometimes fail? • Proactive and Retroactive interference • Proactive interference • Previous memories disrupt current memory • Where did I park my car today? • Retroactive interference • New memories disrupt old memories • Cumulative exams? • Phone number from last apartment? • Address?

32. Amnesia • Anterograde • Unable to form memory for events that occurred after the injury • Retrograde • Loss of memory for events prior to injury • Squire’s electroconvulsive shock study • Indicates that memories are vulnerable for an exceptionally long time • 1 year old memories were especially vulnerable • Older memories were relatively unaffected • Implies some active processing of memory (memory consolidation) over an extended period of time.

34. Directed Forgetting • It is known that humans can exert cognitive control over memory. • Give a list of words to subjects to remember • Tell them “okay – that was just practice. Forget about that list and get ready for the real list” • After a retention interval you tell them that you lied. • Please write down as many words from the original list that you can • Compare to a group told to remember the list. • Memory for the list is much poorer for those told to forget. • Perhaps because they did not initiate memory maintaining strategies (rehearsal)

35. Can animals exert cognitive control over memory? • Omission Procedure • Phase 1 MTS • R R+G- • GG+R- • Phase 2 DMTS with cues • R-VR+G- • G-VG+R- • R-HITI • G-HITI • Test • with forget cues • R-HR+G- • G-HG+R- • Compare to remember cues • R-VR+G- • G-VG+R- • Result? • Good performance on R-cued trials • Poor performance on F-cued trials

36. Problems with Omission Procedure? • Roper and Zentall (1993) • 1. no response requirement following F-cues • Pigeons are not used to making a choice following F-cues • Thus, disrupts responding in test • 2. no RF following F-cues. • F-cue could act as a conditioned inhibitor • Thus, disrupt responding in test • 3. Presentations of comparisons following F-cues is novel • The novel (or surprising) cues could disrupt performance

37. The substitution procedure corrects for the above issues. • Substitution Procedure • Phase 1 MTS • R R+G- • GG+R- • Phase 2 DMTS with cues • R-VR+G- • G-VG+R- • R-HB+Y- • G-HB+Y- • Test • with forget cues • R-HR+G- • G-HG+R- • Compare to remember cues • R-VR+G- • G-VG+R- • Result? • Good performance on all trials • No evidence for directed forgetting

38. Compare the human situation to that of the pigeon • Maintaining a bunch of words in memory is demanding • Difficult to do • The pigeons do not have nearly the same demands • one sample to remember • Red or Green • There may be little cost to remembering regardless of the trial type. • What if we increase the memory demand? • Reallocation experiment • Roper, Kaiser, and Zentall (1995) • Train the pigeons with F-cues that they have to remember • If they have to reallocate memory to the F-cue perhaps it will disrupt memory for the original sample