This is a basic finding in experimental economics (Thaler comes to mind, but it's been a while). I remember an experiment showing this in my first class in '03 which we used as a case study for many, many lectures that followed. That it also holds for babies is quite cool. It's innate that we have strong preferences for things we have in our hands! Even if exactly it getting in our hands is totally random.
Edit: Endowment effect with one famous experiment with mugs from Kahneman (1990). That's the one we replicated in class. Pretty cool come to think of it to use a famous experiment as a first introduction to the field.
Note that the endowment effect does not exist when the value of the object in question is well understood. This makes perfect sense; in the words of something I read recently about the working of financial markets, "if somebody wants to trade with you, your first thought should be 'what does he know that I don't?'"
> Even if exactly it getting in our hands is totally random.
But only if (we think) it's our own doing, right? Because (per another comment - I haven't paid to read the study) they didn't see the same effect if they gave the babies the toy.
Edit: Endowment effect with one famous experiment with mugs from Kahneman (1990). That's the one we replicated in class. Pretty cool come to think of it to use a famous experiment as a first introduction to the field.
[1] https://en.m.wikipedia.org/wiki/Endowment_effect