Fish pass mir­ror test, but does it mean they’re self-aware?

Decades-old mir­ror test doesn’t pro­vide a de­fin­i­tive answer

Sun Sentinel Broward Edition - - Nation & World - By Mal­colm Rit­ter

NEW YORK — Sci­en­tists re­port that a fish can pass a stan­dard test of rec­og­niz­ing it­self in a mir­ror — and they raise a question about what that means.

Does this decades-old test, de­signed to show self­aware­ness in an­i­mals, re­ally do that?

Since the mir­ror test was in­tro­duced in 1970, sci­en­tists have found rel­a­tively few an­i­mals can pass it. Most hu­mans can by age 18 to 24 months, and so can chimpanzees and orang­utans, says the test’s in­ven­tor, evo­lu­tion­ary psy­chol­o­gist Gor­don Gallup of Al­bany Col­lege in New York.

Out­side of ape species, many re­searchers say there’s also good ev­i­dence for pass­ing the test in bot­tlenose dol­phins, Asian ele­phants and Euro­pean magpies, although Gallup is skep­ti­cal. .

The test ex­poses an­i­mals to a mir­ror and looks for re­ac­tions that in­di­cate some recog­ni­tion of them­selves. For ex­am­ple, do the an­i­mals do un­usual things to see if the im­age copies them? Do they ap­pear to use the mir­ror to ex­plore their own bod­ies? And if re­searchers mark an an­i­mal in a place the crea­ture can ob­serve only in the mir­ror, does the an­i­mal try to re­move it?

Pass­ing the test sug­gests an an­i­mal can “be­come the ob­ject of its own at­ten­tion,” and if it does, it should be able to use its own ex­pe­ri­ence to in­fer what oth­ers know, want or in­tend to do, said Gallup, who did not par­tic­i­pate in the fish study.

The new pa­per re­leased last week by PLOS Bi­ol­ogy sub­jected up to 10 fish to var­i­ous parts of the test.

Alex Jor­dan, who’s at the Max Planck In­sti­tute for Or­nithol­ogy in Ger­many, and col­leagues ob­served a reef-dwelling species called the cleaner wrasse do­ing odd be­hav­iors such as swim­ming up­side-down by the mir­ror. When four fish were in­jected with a tag that left a vis­i­ble brown mark un­der their throats, three scraped that part of their bod­ies against a rock or the sandy bot­tom of the tank, as if try­ing to re­move it.

In all, the re­searchers con­cluded that the fish had passed the test. But Jor­dan says his fish could have suc­ceeded with­out pos­sess­ing true self-aware­ness.

They may have matched the re­flec­tion to parts of their own bod­ies, but he said that less-so­phis­ti­cated men­tal tal­ent doesn’t re­quire self-aware­ness, which in­cludes tal­ents such as dis­tin­guish­ing their own bod­ies from those of other fish or rec­og­niz­ing their own ter­ri­tory or pos­ses­sions. Nor does it im­ply self-con­scious­ness, which means think­ing about one­self and one’s own be­hav­ior in re­la­tion to how oth­ers act, he said in an email.

Gallup said he be­lieves the ex­per­i­men­tal pro­ce­dure was flawed, so the fish can’t re­ally be said to have passed the test.

Frans de Waal, an ex­pert on ape and mon­key be­hav­ior at Emory Uni­ver­sity’s Yerkes Na­tional Pri­mate Re­search Cen­ter in At­lanta, said he found the fish re­sults in­con­clu­sive.

In a jour­nal com­men­tary, de Waal also said it’s bet­ter to think of dif­fer­ent an­i­mals hav­ing vary­ing de­grees of self-aware­ness, rather than con­sid­er­ing it an all-ornoth­ing trait pos­sessed by just a few species.

“To ex­plore self-aware­ness fur­ther we should stop look­ing at re­sponses to the mir­ror as the lit­mus test” and turn to other means of eval­u­a­tion, he said.


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