Interesting article reported. A group of domestic horses was taught to touch symbols with their noses, whether they want to be covered with a blanket. All horses learned three symbols: 'put blanket on me', 'take blanket off me' and 'no change' within two weeks. Horses can use symbols to talk to us | Science | AAAS 'The horses did not touch the symbols randomly, but made their choices based on the weather. If it was wet, cold, and windy, they touched the "blanket on" icon; horses that were already wearing a blanket nosed the “no change” image. But when the weather was sunny, the animals touched the "blanket off" symbol; those that weren’t blanketed pressed the “no change” icon. The study’s strong results show that the horses understood the consequences of their choices' I immediately thought about zoos. Zoo staff often struggles to learn animal preferences to food, exhibit, cover and so on. Here is the proof that even less smart animals can themselves show what they want. I read earlier that even goldfish had distinct likes and dislikes. The challenge was how to show it. The solution was that the fish swum through the ring when it wanted light on or off. Now, I can imagine that in a future zoo, zebras, elephants or apes will have a series of levers in their paddocks: 'want apples today' 'want a carrot' 'I sh**ed, clean after me' 'let me inside' 'let me out' 'scratch me' and so on.
the paper itself is here: http://www.appliedanimalbehaviour.com/article/S0168-1591(16)30219-2/abstract (click on Full Text to read it). I think the author of the popular article to which Jurek linked only read the abstract and formed their article around that. The paper itself has a lot more information.