A new study published in the Proceedings of the National Academy of Sciences shows that ravens appear to share negative emotions.
The researchers started with offering birds two boxes placed on the left and right sides of the animals. While one box was empty, the other contained a piece of cheese (yum!). They then placed a box in a new location and examined how the birds responded. If a bird acted like it expected a treat, that was thought to indicate optimism. Likewise, if a bird acted like the box was empty, that was thought to be indicative of pessimism. Kind of like a glass half empty vs half full test.
For the next part of the study, the researchers gave ravens raw carrots (not appealing) and dry dog food (who could ask for more?). They then took away one of the meals. When the researchers left the carrots, the birds spent time scratching and kicking and not interested in the meal. Not too different from a picky child. The researchers also measured the responses of other birds observing this event but not able to see the food that was offered. They then repeated the cognitive test for pessimism vs optimism bias.
What they found was fascinating – when an observer bird witnessed a peer’s reaction to the dog food, the observer showed similar interest in their own mystery box. However, those that observed a peer’s response to carrots took longer to show interest in the mystery box indicating the sharing of negative emotions.
The ability to share bias is an important tool for communication and decision making in social groups. Shared aversion to foods may also serve to protect peers from eating foods that may be harmful.
This experiment reminds me of family meals when I was a kid and my parents served something my siblings did not like so naturally I assumed before even trying it that I would not like it either. Although, personally, I would choose carrots over dog food any day.
Categories: Comparative Physiology