Bias:
Sound (music, dubbed sounds and verbals) can change how we perceive a behavior or event.
Watch this short video without sound first. Write down your overall perception of the puppies.
Watch video
Then watch it again with sound. Write down your overall perspective.
Has it changed?
This is why I usually watch any video footage with the sound turned off first, then add it back in as background context. (And is also a good lesson on how editing can make things seem what they aren't.)
(even the title adds bias!)
Enjoy!