BiWire Jumpers on biwireable speakers.

[Jean-Marie]

But there's also the personal reasons. Mood is one of them. 

That's a big one! 

That means we can 'hear' differently depending on how we feel.

That´s why!
I wondered how it was possible to notice a difference between those two types of connection, and here´s the reason: my mood changed every time I got up to change the terminals.
Much more enlightened now ... and relieved.

That’s exactly what ABX and other double blind tests are for: eliminating the biases brought by our brain, mood and other things. 

Unfortunately, doing one in this case would require a electric switching box to move quickly between the two configurations. 

So I’m definitely in the camp of @Pim and others who say that the way you connect does not make any difference. 

But on the other hand, we listen more with our brain and mood than ears, so if one way pleases you more than the other, go for it. This is a easy and cheap way to be happy, even if it is just in our brain. 

Jean-Marie