04.11.2020: Whether animals can recall certain object features and actively reproduce them is largely uncharted. Researchers from the University of California Los Angeles, the University of Vienna, the University of Bristol, the University of Auckland and the University of Veterinary Medicine Vienna around Isabelle Laumer and Alice Auersperg investigated for the first time whether Goffin cockatoos can manufacture paper objects based on different memorized model features.

What shape are a fox´s ears? Most people visualize the corresponding image before answering the question. Humans can represent information in multiple ways and use mental templates to actively produce memorized patterns, for example, when drawing a sketch or when mentally simulating complex processes. But how can we investigate this ability in animals, which cannot share their perception and inner worlds through spoken language?

In non-human animals the ability to recognize information is typically assessed in delayed matching-to-sample tasks using computerized touchscreen designs, where the focus is usually on how long certain animal species can keep specific object features in memory. Recall, on the other hand, requires the animal to specifically reproduce remembered information and this ability is largely uncharted. So far, there is evidence that rhesus macaques can reproduced two-dimensional shapes, after a delay, by aligning two or three coloured boxes on a touchscreen grid. So far, it is unknown if other animals outside primates share this abil

Cognitive biologist Isabelle Laumer and colleagues assessed this ability in an Indonesian parrot species, the Goffin´s cockatoo. Although these birds do not use tools routinely in the wild, they can use and manufacture tools and even innovate new tool designs, which is very rare in the animal kingdom. “The cockatoos were first trained to insert carved strips of paper into a tube in order to receive a piece of cashew. Each strip was manufactured by a large number of bite marks alongside the edge of the paper”, explains Isabelle Laumer that conducted the study. “ Then the Goffins had to learn that only one colour out of two differently coloured, pre-made paper strips was rewarded. In the test, the cockatoos could decide to manufacture a strip out of one of two differently coloured paper squares. We found that they selected the paper in the same colour as the previous template.”

But can they manufacture paper strips in the same length as previously experienced templates from memory? First the cockatoos were divided into two groups, with one group being rewarded for inserting short pre-made strips, while the other group was rewarded for dropping long strips. In the test, the experimenter placed a squared paper card on the table and the cockatoos were given the opportunity to manufacture a strip from it. “Interestingly, the birds manufactured shorter pieces when they had previously learned that short templates were rewarded and longer strips when they had experienced long templates before. And they were able to switch and carve strips in the other size as well", says Laumer. “Our results suggest that Goffin’s cockatoos can recall and achieve the active assimilation of an object to specific features such as size and colour of a memorized object through manufacture, despite being rewarded at random and in the absence of the respective template.”

However, the researchers found no evidence that the cockatoos could carve L-shaped pieces after learning that L-shaped templates were rewarded, though their manufactured strips were wider than in previous tests. “The cockatoos might have faced morphological and ergonomic constraints, since the distance between the beak tip and the edge of the horizontal part of the upper mandible allows only to carve out objects in a certain width. Nevertheless, in three individual instances two animals carved out a small stripe and folded it with the resulting product resembling an L-shape”, says Alice Auersperg, last author and head of the Goffin Lab in Austria. The ability to recall and reproduce colour and size of a template has previously only been shown in New Caledonian crows, that routinely use and manufacture tools in the wild to fish for larvae in decaying wood. “Finding the ability to physically produce object features of a template in a parrot that has the capacity for tool innovation but, so far, seems to lack a dependency on tool use and does not have tool cultures suggests that the latter is not a necessary condition in order for this ability to evolve."

The article "Object manufacture based on a memorized template: Goffin’s cockatoos attend to different model features" by IB Laumer, SA Jelbert, AH Taylor, T Rössler and A Auersperg was published in Animal Cognition. 

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Filmed test
 

Image description: a)Training in preparation for the Colour test. b) Training in preparation for the Size test. c) Test: Goffin carves a strip of paper by applying a large number of bite marks alongside the edge of the paper. Different colours of paper were used in each condition. d) Test: Goffin inserts the manufactured strip into the large tube. Afterwards a food reward is placed in the small tube (Photos by Bene Croy).