More cuttlefish

It’s cuttlefish time again, with reference 1 having recently come to my attention. With their last popping up, a something over a year ago now, at reference 2. Where I am reminded of reference 4, so perhaps time to take another look at all the cuttlefish there – certainly more likely than most of the 90 references offered in the present paper.

Reference 1 is couched in terms of delayed gratification, something which humans have to learn about if they are to get on in the world, and something which some animals can do, including cuttlefish. Reference 1 tells us that great apes, crows and parrots can do it, while some monkeys, rodents, chickens and pigeons can’t, finding it difficult if not impossible to inhibit the consumption of a desirable food item for a delayed gain.

I suppose that having food preferences at all is a sign of evolutionary maturity, an advance on a simple binary classification of the outside world into food and not food.

The carnivorous cuttlefish have sophisticated foraging strategies, demonstrating intelligence at work. They also have clear preferences, so if given the choice they will take, for example, live grass shrimp (Palaemonetes paludosus) rather than the rather larger Asian shore crab (Hemigrapsus sanguineus).

The present paper investigates how long cuttlefish are prepared to wait in expectation of shrimp if crab is available. Or chunks of king prawn, intermediate between the two. And the answer seems to be up to around two minutes. It also seems that the fish that could delay more, also turned out to be more intelligent. From which it does not follow that training your child to delay gratification will make it more intelligent: more work needed on that point. With the closing words of the paper being: ‘our results also provide the first evidence of a link between self-control and learning performance in a non-primate animal’ – being a suitably modest closure.

As is often the case, I worry about sample sizes, without having the time or energy to think about them properly. In this case just six cuttlefish raised in 2018 in the US from eggs collected in the English Channel. Nine months old at the time of the experiments – in a natural life of the order of a couple of years or so – all spent in the aquarium. Not clear (to me) why they needed to use UK eggs so far away in the US.

Not exactly new news, which must be frustrating for the researchers concerned, even if they get the plum of eventual publication in a superior journal. More delayed gratification!

Interested to see that some of the experimental apparatus was built using a 3-D printer. Not just toys for the boys.

References

Reference 1: Cuttlefish exert self-control in a delay of gratification task - Alexandra K. Schnell, Markus Boeckle, Micaela Rivera, Nicola S. Clayton and Roger T. Hanlon – 2021.

Reference 2: https://psmv4.blogspot.com/2020/02/intelligent-feeding-of-cuttlefish.html.

Reference 3: Cuttlefish show flexible and future-dependent foraging cognition - Pauline Billard, Alexandra K. Schnell, Nicola S. Clayton and Christelle Jozet-Alves – 2020. The paper noticed at the post at reference 2. Reference 49 in the present paper, reference 1 above.

Reference 4: Other Minds: The Octopus and the Evolution of Intelligent Life - Godfrey-Smith, Peter – 2017. It only took me about five minutes to put my hand on it. The shelving arrangements do work.