# Which proportion of species of non human animals exhibit a "forgetting curve" similar to that of humans?

SHORT QUESTION:

Are there some experimental results supporting the existence of a "forgetting curve" in most non human animals similar to that of humans?

BACKGROUND and REFERENCES:

Spaced repetition techniques consist in testing the memory about topic $$X$$ right before it would be forgotten according to the prediction from the forgetting curve, so that to keep the information related to $$X$$ in long term memory rather than forgetting it. It seems that it can be applied to facts, but also to more complex concepts.

The forgetting curve has been mostly observed in the memory model of humans, but I could find ONE study (and a quite recent one) of it in a non human species: In their 2021's article, Reynoso-Cruz et al. describe some (limited) indication of such a forgetting curve in the memory model of spider monkeys.

My understanding of the theory behind forgetting curve is that (positive) memories (e.g. finding food in a specific place) need to be reinforced regularly to stay in long term memory (e.g. to avoid memorizing too many locations where good food was found only accidentally, and focus memory on places where good food is regularly found). [This is less true about negative memories, because there is an evolutionary advantage in memorizing an "accidental" life threatening event even if it does not repeat.]

• If the latter is true, then most animals with a memory should show some form of forgetting curve.
• Are there some experimental results supporting such hypothesis? (Other than Reynoso-Cruz et al.'s?)