Perhaps not surprising, working breeds – many of which are known to have been artificially selected for high toy or predatory motivation – were overrepresented in the sample. This is the vibe I get from my golden retriever. Chasing the tennis ball is more than play, it's a justification for life, her contribution to the pack. Actually eating food has a higher priority than chasing the ball, but not much else does. Wh…
I grew up with a cocker spaniel obsessed with tennis balls to the point of covering his food with them and letting it rot. Looking into his eyes conveyed no emotion and he didn't seem to care much for affection. He was a tennis ball tracking machine. There was nothing you could do to satiate his desire. If you gave in to a catch session, you could throw it 100 times, he would start coughing/convulsing from exhaustion…
Edit: He gets plenty time with other people and dogs - not its not like he is starved for attention.