Hi there, I am Hang, and today I’d like to share with you an interesting study that I discovered in my 3rd year Neuroscience memory module.
In research, experimentation using biological model organisms (most commonly rodents) is an important way to discover neurobiological mechanism and behaviour, but in this study investigators use the lesser studied scrub jay, to understand their abilities to retain episodic-like memories and planning for the future. The scrub jay (or to you latin lovers, Aphelocoma californica) is a beautiful blue winged species of bird native to western North America.
Episodic memory is a powerful brain tool that usually provides an individual with the time when something happened, what happened and where it happened. For example, I can remember that at 4pm yesterday I was doing exercises at home, and I can, in my mind, re-experience those events (I was huffing and puffing and feeling rather unfit, as I recall).
Researchers in this study wanted to test whether animals have only semantic (and not episodic) memories. Semantic memory is based on “knowing” in the broadest sense, for example, knowing that the Earth revolves around the sun.
Scrub jays are a type of bird that, like squirrels, also bury food to save for the hard food-poor Winter months. Unlike squirrels, who tend to forget up to 74% of the nuts and acorns that they bury (which interestingly is thought to lead to oak forest regeneration) scrub jays are much better at remembering where they leave their goodies.
In this experiment, scrub jays are provided with nuts, which are suitable for long-term storage, and wax worms, which are more preferred but are highly perishable compared to nuts. The scrub jays were given peanuts and wax worms to bury and were allowed to come back and recover them at a later time point. After 4 hours, the birds return and retrieve wax worms but not peanuts. However, if left waiting for 124 hours, they return straight to the peanuts whilst completely skipping the wax worms, knowing that by then the worms would have decayed.
This behavior demonstrates that not only do scrub jays retain the memory of when and where the different foods were buried but are also able to distinguish between the perishability (and thus viability) or their resource. Now that is one smart episodic-memory utilizing bird.
This is one of the many interesting experiments performed using scrub jays in the study! Check out the rest in the below paper.
By Hang Nguyen
Clayton, N., Bussey, T. & Dickinson, A. Can animals recall the past and plan for the future?. Nat Rev Neurosci 4, 685–691 (2003). https://doi.org/10.1038/nrn1180 (There is actually a mistake in this paper, check it out to see if you can find it!)
University of Richmond. "Researchers Tackle The Nutty Truth On Acorns And Squirrels." ScienceDaily. ScienceDaily, 26 November 1998. <www.sciencedaily.com/releases/1998/11/981126102802.htm>.