This is what the researchers claim to have shown:
Here we show that 6- and 10-month-old infants take into account an individual’s actions towards others in evaluating that individual as appealing or aversive: infants prefer an individual who helps another to one who hinders another
What they actually did was show babies a kind of puppet show and get them to pick a triangle or a square afterwards (apparently they varied the symbol/colour to rule out any effect from appearance alone but I haven’t checked the methods section myself). Call me sceptical, but I’m not convinced that picking a square or a triangle equates to preferring an “individual”.
I’d like to believe it’s true. But watching my own child hasn’t convinced me that such young children are capable of such sophistication. And while it’s undoubted true, as the researchers point out, that all social animals benefit from the ability to distinguish friend from foe, does it really help six-month-old babies?
I’m reserving judgement until the studies are repeated with humans rather than wooden symbols.