In the famous ‘marshmallow test’, a child receives a marshmallow and a choice: eat it straight away, or wait 15 minutes and get a second one. Some children can delay gratification — and researchers have found that the same is true for the humble cuttlefish.
Alexandra Schnell at the University of Cambridge, UK, and her colleagues devised a modified version of the marshmallow test for common cuttlefish (Sepia officinalis), marine invertebrates related to octopuses. The researchers analysed how often the animals chose to wait for their favourite snack — a live grass shrimp — rather than eat a less-preferred but already available prey item. At any time, the animals had the option to stop waiting and eat the available prey.
Cuttlefish waited for up to 130 seconds to get the live grass shrimp, although as the delay increased, the animals became more likely to take the immediate reward. Cuttlefish able to hold out for longer performed better on tests that measured learning skills.
This is the first evidence of a link between self-control and learning performance in a non-primate animal, the researchers say.