Eurasian Jays Come Through Their Marshmallow Test

Eurasian jays (Garrulus glandarius) are intelligent Corvids (members of the Crow family). It's now been demonstrated that these birds can put off grabbing an mediate food reward, if this gives them the possibility of getting a tastier item, later (https://www.theguardian.com/environment/2022/oct/31/eurasian-jays-show-ability-to-exert-self-control-study-finds). The marshmallow test was carried with children. Most children could show sufficient self-control, by not immediately eating a marshmallow, after learning that two of these tasty treats would be available, to those who waited a defined period of time. Tests with the Jays involved the birds being given access to drawers with windows. Some drawers contained immediately accessible, but not very tempting food items (a bit of bread or cheese). Other drawers contained more preferred food items but would only unlock after a short delay. The birds initially had to learn that openning a drawer, resulted in all the other drawers being permanently locked. Most Jays showed sufficient self-control to wait for access to the tastier items. Jays, assessed as more intelligent on other tests, learned this task most quickly. The authors of this study suggest there is a strong association between self-control and intelligence. This seems to apply to a wide range of species, including the Octopus (an intelligent Mollusc).