Was that fish on your plate once a sentient being? Scientists have long believed that the animals aren't capable of the same type of conscious thought we are because they fail the "emotional fever" test. When researchers expose birds, mammals (including humans), and at least one species of lizard to new environments, they experience a slight rise in body temperature of 1°C to 2°C that lasts a while; it's a true fever, as if they were responding to an infection. The fever is linked to the emotions because it's triggered by an outside stimulus, yet produces behavioral and physiological changes that can be observed. Some scientists argue that these only occur in animals with sophisticated brains that sense and are conscious of what's happening to them. Previous tests suggested that toads and fish don't respond this way.
Now, a new experiment that gave the fish more choices shows the opposite. Researchers took 72 zebrafish and either did nothing with them or placed them alone in a small net hanging inside a chamber in their tank with water of about 27°C; zebrafish prefer water of about 28°C. After 15 minutes in the net, the team released the confined fish. They could then freely swim among the tank's five other chambers, each heated to a different temperature along a gradient from 17.92°C to 35°C. (The previous study used a similar setup but gave goldfish a choice between only two chambers, both at higher temperatures.) The stressed fish spent more time—between 4 and 8 hours—in the warmer waters than did the control fish, and raised their body temperatures about 2°C to 4°C, showing an emotional fever, the scientists report online today in the Proceedings of the Royal Society B. Thus, their study upends a key argument against consciousness in fish, they say.
(Score: 2) by Wootery on Friday November 27 2015, @06:56PM
See also a relevant paper Can fish really feel pain? [hu-berlin.de] (Paper takes the side of 'no'.)
(Score: 0) by Anonymous Coward on Saturday November 28 2015, @11:52AM
Paper also has a REALLY hard time keeping medical and metaphysical consciousness separate. Further it ignores multiple studies (which predate this paper) that show the brain still reacts to "pain" even in an unconscious state (contrary to their claims).
Reading through that paper it becomes very obvious it is simply a literature review with an axe to grind. Interesting none the less but hardly useful science on the subject.