Ravens Plan for the Future; Rats Know When They've Forgotten

New research on the cognitive lives of animals is yielding interesting results.

Posted Jul 27, 2017

Ravens plan for the future

I'm always looking for new research on animal cognition and just how smart nonhumans can be. Two studies caught my eye this week. This first centers on an essay published in New Scientist by Anil Ananthaswamy called "Ravens can plan for future as well as 4-year-old children can," which summarizes a research paper by Lund University's Can Kabadayi and Mathias Osvath published in Science titled "Ravens parallel great apes in flexible planning for tool-use and bartering." The abstract for the original paper, which is not available online, reads:

The ability to flexibly plan for events outside of the current sensory scope is at the core of being human and is crucial to our everyday lives and society. Studies on apes have shaped a belief that this ability evolved within the hominid lineage. Corvids, however, have shown evidence of planning their food hoarding, although this has been suggested to reflect a specific caching adaptation rather than domain-general planning. Here, we show that ravens plan for events unrelated to caching—tool-use and bartering—with delays of up to 17 hours, exert self-control, and consider temporal distance to future events. Their performance parallels that seen in apes and suggests that planning evolved independently in corvids, which opens new avenues for the study of cognitive evolution.

In Kabadayi and Osvath's experiment, ravens were trained to use a stone to open a puzzle box that contained dog food. The box was then moved out of the ravens' sight and an hour later the birds were presented with an array of objects, including the stone. The ravens chose the stone 86% of the time even when they couldn't see the box, which was returned 15 minutes later. It's important to note that the stone was of little use on its own and the birds didn't know they would see the box again. The researchers argue that they were planning for the future. 

In another experiment, ravens were trained to barter a blue bottle cap, called a token, for food. Later on they were asked to select the correct token in a location different from where the original training took place, hold on to it for 15 minutes, and then swap it for food. As with the stone in the first experiment, the blue bottle cap had no value in and of itself and the ravens didn't know they would have the opportunity to swap the cap for food in the future. 

In his excellent summary, Ananthaswamy notes that the ravens planned for future events that they wouldn't encounter in the wild, "so it isn’t an adaptation to an ecological niche, but rather a flexible cognitive ability that evolved independently in birds and hominids, whose lineages diverged about 320 million years ago."

I find these results to be extremely compelling, but not all researchers agree. In an essay by Ed Yong called "Ravens Can Plan for the Future," Oakland University's Jennifer Vonk, who also studies ravens, wonders, "If the ravens don’t actually know when they’ll encounter the puzzle box ... how do they know which item to select? Since they were trained to use the stone to open the box, and since the stone was the only object that ever did so, 'it makes sense that the birds would develop a preference for that tool,'” Vonk adds. 'It isn’t clear that this preferential selection reflects future planning.”

In the same essay, Yale University's Laurie Santos notes, “'The current results show that birds value objects that they know might be valuable later. It’s nice evidence for forward planning, but I don’t think it shows that the birds are thinking of themselves in the future in any rich way.'”

In Ananthaswamy's piece, Marcus Boeckle of the University of Cambridge notes “'This is new, very exciting evidence which we didn’t have before ... '[It’s evidence] that general intelligence has also developed in birds. This is very important for understanding how intelligence evolves.'”

Clearly more work has to be done, and how exciting it will be to see how ravens and other animals plan for future events. I often go to empty cupboards so I'm not sure how I'd do on these tests. For more information on the skills of ravens please see "Ravens Know They're Being Watched: Bird Brain Theory of Mind," an interview I did with bird cognition expert Dr. Nathan Emery called "Bird Brain: An Exploration of Avian Intelligence" about his excellent book titled Bird Brain: An Exploration of Avian Intelligence, and essays by Psychology Today writers John Marzluff and Tony Angell  in their posts on "Avian Einsteins." 

Rats know when they've forgotten stuff

The second study I found very interesting deals with rats knowing what they can remember. In an essay by Diana Crow called "Rats can tell when they’ve forgotten something, just like us" we learn "Much like students doing a test, rats tend to skip questions when they have forgotten the answer. A series of smelly experiments suggests rats are aware of what they remember, and behave differently when they can’t recall something." Crow is writing about a recent study published in the journal Animal Cognition by Victoria Templer, Keith Lee, and Aidan Preston titled "Rats know when they remember: transfer of metacognitive responding across odor-based delayed match-to-sample tests." The abstract reads:

Metamemory entails cognitively assessing the strength of one’s memories. We tested the ability of nine Long-Evans rats to distinguish between remembering and forgetting by presenting a decline option that allowed a four-choice odor-based delayed match to sample (DMTS) tests to be by-passed. Rats performed significantly better on tests they chose to take than on tests they were forced to take, indicating metacognitive responding. However, rather than control by internal mnemonic cues, one alternative explanation is that decline use is based on external test-specific cues that become associated with increased rewards over time. To examine this possibility, we tested rats on three generalization tests in which external contingencies were inconsistent and therefore could not serve as discriminative cues. Rats transferred adaptive use of the decline response in tests that eliminated memory by presenting no sample, increased memory by presenting multiple samples, and both weakened and strengthened memory by varying the retention interval. Further, subjects chose to take or decline the test before encountering the memory test, providing evidence that rats based their metacognitive responding on internal cues rather than external ones. To our knowledge, this is the first robust evidence for metamemory in rats using the DMTS decline-test paradigm in which several possible sources of external stimulus control can be ruled out.

I offer the complete abstract because it shows just how carefully this project was carried out. In her essay Crow captures the essence of this study. Rats were first trained to dig through sand to sniff samples of cinnamon, thyme, paprika, or coffee. They then had to go to a dish with the same scent. If the rats chose the correct dish they were rewarded with a piece of cereal. Crow goes on to write, "But there was a twist. Although rats that chose a dish with the wrong scent got no reward, rats that positioned themselves next to a fifth, unscented dish received a quarter-piece of the cereal. This meant that when rats forgot what they had smelled in the sand, their best bet was to pick the unscented dish – provided they could tell that they had forgotten the relevant smell."

But the story gets more interesting: When rats chose the wrong dish they received no reward. However, when they chose the unscented dish they were rewarded with 1/4 piece of cereal. So, if rats forgot what they smelled they were better off picking the unscented dish. Lead researcher Victoria Templer notes that since the "rats’ performance improved when the unscented dish was available as an opt-out ... this shows the rats weren’t simply choosing the unscented dish for no reason. They seem to have known that declaring that they had forgotten would still earn them a small reward."

Both of these studies are wonderful examples of the groundbreaking comparative research that is being conducted on animal minds. Please stay tuned for more coverage of the incredibly exciting research that's being conducted on the cognitive lives of animals. 

Marc Bekoff’s latest books are Jasper’s Story: Saving Moon Bears (with Jill Robinson); Ignoring Nature No More: The Case for Compassionate Conservation; Why Dogs Hump and Bees Get Depressed: The Fascinating Science of Animal Intelligence, Emotions, Friendship, and Conservation; Rewilding Our Hearts: Building Pathways of Compassion and Coexistence; The Jane Effect: Celebrating Jane Goodall (edited with Dale Peterson); and The Animals’ Agenda: Freedom, Compassion, and Coexistence in the Human Age (with Jessica Pierce). Canine Confidential: Why Dogs Do What They Do will be published in early 2018. Learn more at marcbekoff.com.

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