Well, sure, its curiousity if you break it down to its simplest form.
Perch thaught process = What is that? Can I eat it? What part can I rip off?
...and the only reason why you see sometimes 20 fish chasing it is because each fishes movement entices the neighbouring fish to beat the other one too it ( the moving bait ), then who ever has the "biggest set" attacks first... they wait for another to bite first, then attack.
I'm not saying this is what happens with perch, but I've worked with fish for over 5 years now and that the pattern I've noticed from feirce predatory fish, to big fat nearly 3 feet long koi, and I've noticed this with all fish.
You should snorkel with a bunch of perch, really fun, bring some worms and you'll have a blast. I've fed them by hand before.
It can be anything, shiny or not.