Is the ability to empathize uniquely human? This question has long been pondered by philosophers and animal behaviorists alike. Empathy depends in part on the ability to recognize the wants and hopes of others. A new study by researchers at the University of Cambridge suggests that we may not be alone with this ability.
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| A male Eurasian jay feeds his female mate. Photo provided by Ljerka Ostojić. |
Ljerka Ostojić, Rachael Shaw, Lucy Cheke, and Nicky Clayton conducted a series of studies on Eurasian jays to explore whether male jays could perceive changes in what their female partners desired. Eurasian jays are a good species with which to explore this phenomenon because males routinely provide food to their female mates as a part of their courtship. The researchers wanted to know if males would adjust what food items males offered their mates depending on what food type the females wanted more.
In order to make a female prefer one food type over another, the researchers fed each female one of two food types (wax moth larvae and mealworm larvae) until they were full. But being full of one type of food doesn’t mean you can’t find room for desert, right? So when the researchers then offered the females access to both wax moth larvae and mealworm larvae, those that had previously eaten wax moth larvae now preferred mealworm larvae and those that had previously eaten mealworm larvae now preferred wax moth larvae. But could their male partners tell what they preferred at that moment?
In order to test whether male jays were sensitive to their partners’ desires, the researchers fed the females either wax moth larvae or mealworm larvae until they were full. They did this while their male partners watched from behind a transparent screen. They then removed the screen and gave the males 20 opportunities to choose between a single wax moth larvae or mealworm larvae to feed their partner. In this context, males usually chose to share with their mates the food that their partners preferred rather than the food their partners had already been fed! But are the males responding to their mate’s behavior or are they responding to what they saw when the females were eating earlier?
This video (provided by Ljerka Ostojić) shows the experimental process
in which the male chooses a food type and then shares it with his mate.
The researchers repeated the study with an opaque screen so the males could not see their mates while the females gorged on one particular food type. Without the ability to see the mate eating beforehand, males chose both food types equally and did not attend to their mate’s preferences. Because the females still had a preference for the opposite food type but the males were not adjusting for that preference, this means that the males are not responding to their mate’s behavior in this experiment or the previous one. This suggests that if male Eurasian jays see what their mates are eating, then somehow they have the ability to know to give their mate the opposite food type!
Whether this process involves the males having an understanding of their mate’s desires or some other mechanism is not fully known. But male Eurasian jays are certainly adjusting what they give their mates according to what she wants. Now if we can only teach human males to do that!
Want to know more? Check this out:
Ostojić, L., Shaw, R.C., Cheke, L.G., & Clayton, N.S. (2013). Evidence suggesting that desire-state attribution may govern food sharing in Eurasian jays PNAS, 110 (10), 4123-4128 DOI: 10.1073/pnas.1209926110
