Episodic Memory in Animals

1. Episodic Memory in Animals �Episodic memory is the form of memory that allows an individual to recollect happenings from his or her past.� (Tulving, 1992)? ---> Do animals have Episodic Memory? K�stenseeschwalbe = Artic tern, Sterna paradisaeaK�stenseeschwalbe = Artic tern, Sterna paradisaea

2. Tulving's view

3. Semantic and Episodic Memory According to Tulving and Markowitsch (1998), the relation between Declarative/ Semantic and Episodic Memory is one of inclusion: while you can have sem M without EM, you cannot have EM without sem M.

4. What is special about EM? 1. conscious recollection of past experiences 2. At the moment of retrieval, oriented to the past 3. Accompanied by autonoetic consciousness, allowing for 'Remembering' instead of 'Knowing' 4. Embedded relationship: EM ? sem M 5. EM develops later in children than sem M 6. EM is more vulnerable (amnesia, aging)? 7. EM is dependent on PFC, according to Tulving on the hippocampus 8. Unique to humans?

5. Consciousness in animals? Especially the properties that relate to conscious experience of recollection of past episodes are an unsurmountable obstacle for the attribution of EM to animals since there are no agreed behavioral markers of conscious recall in animals.

6. The 'what', 'when', and 'where' of an episode Studying EM in animals becomes more tractable when the 'old' definition of EM (Tulving, 1972) is applied: EM is �the retrieval of informtion about 'where' a unique event or episode took place, 'what' occurred during the episode, and 'when' the episode happened.� These spatio-temporal properties of EM can be demonstrated in the behavior of animals.

7. Alternative explanations of animals' behavior, example Animals have EM Rats remember where the hidden platform in the water is and swim to this platform on the next occasion Animals have decl M Rats have acquired knowledge about where in the water the platform is and approach the most familiar location without recollecting the episode when they had been there before

8. General problem: superset-subset relation Since sem. M is a proper subset of EM, sem. M is sufficient to explain the animals' behavior, and since there is no way to prove that animals have EM (or consciousness), the most parsimonious explanation is that animals solve the problem with sem. M. Episodic Memory Semantic Memory

9. Arguments for EM in food caching birds (here: scrub jay) 1. The recollection relates to a single past episode 2. The recollection is accurate and specific: 'when' and 'where'? 3. Birds even remember 'what' they have cached -> it is an adaptive advantage for birds to remember, where, when, and what they have cached, so EM is evolutionary favored.

10. Experimental paradigm(Clayton and Dickinson 1998)? Independent variables: 1. When: Time 1 (4 h later), Time 2 (+120 h later)? 2. Where: Location 1, Location 2 (two adjacent sites)? 3. What: perishable Worms W; non-perish. Peanuts P Dependent varible: number of searches for P and W

11. Experimental paradigm(Clayton and Dickinson 1998)? Peanut/Worm PW trial: 1. Peanut is cached in Location L1 2. 120 h later: Worm is cached in Location L2 3. 4 h later: where will scrub search? Worm/Peanut WP trial: 1. Worms are cached in L1 2. 120 h later: Peanuts are cached in L2 3. 4 h later: where will scrub search?

12. Hypotheses: Degrade Group: Will search for Worms only in P/W trials, since 4 h after caching �W are still fresh� Will NOT search for worms in W/P trials, since 124 h later �W will have perished� Replenish Group: Will search for Worms on both P/W and W/P trials since, in their experience, �Worms are still fresh at 124 h�

13. Results Hypotheses are borne out: D group,P/W trial:W > P R group,P/W trial: W > P D group, W/P trial: P > W R group, W/P trial: W > P

14. Discussion The results cannot be explained by Differential forgetting of Worms and Peanuts Genetic predisposition to prefer worms, but by strategy after learning Crucially, the W/P preference was reversed for the D and the R group after having cached worms for the long interval: only R-birds would recover them, not D birds This requires recall of the following information: 'what':(worms vs. Peanuts 'where': Location 1 vs. 2 'when': short vs. long interval This can hardly be explained by familiarity (sem. M) alone.

15. EM (humans) and E-like M (animals)? Birds show the hallmarks of EM, except �conscious recollection�. �It is this feature that presently makes 'episodic' memory a unique human phenomenon, and probably always will.� (Griffiths et al., 1998, 79)? According to Tulving and Markowitsch (1998), it is impossible to prove the absence of EM in animals, since a universal negative cannot be disproven. The best one can do is to attribute �Episodic-like Memory� to them. E-like M in animals in an analogue in the animal kingdom of EM which is reserved for humans.

16. On a less strict reading the only real difference between men and birds is...

17. References Clayton, N.S., and Dickinson, A.D. (1998): Episodic-like memory during cache recovery by scrub jays. Nature, 395, 272-274. Griffiths, D., Dickinson, A., and Clayton, N. (1999): Episodic memory: what can animals remember about their past? Trends in Cognitive Sciences, 3, 74-80. Tulving, Endel (1972): Episodic and semantic memory. In Endel Tulving and W. Donaldson (Eds.), Organisation of memory. Academic Press, 381-403. Tulving, Endel (1992): Episodic memory. In Larry Squire (Ed.), Encyclopedia of learning and memory. NY: Macmillan Press, 161-163. Tulving, Endel, and Markowitsch, J. Hans (1998): Episodic and Declarative Memory: Role of the Hippocampus. Hippocampus, 9, 198-204. Tulving, Endel (2002): Episodic memory: from mind to brain. Ann. Rev. Psachol, 53, 1-25.