Really? This study doesn’t say what you want it to say here - it looks like the baby is choosing the toy that is least likely to push him back down the slide. Totally in harmony with self interest.
“googly-eyed wooden toy trying to climb roller-coaster hills”
How does the baby know that the wooden toy is trying to climb the hill? For all the baby knows the toy could have been helplessly caught in an anti-gravity vortex, and was only saved by the helpful toy pushing it back down the hill.