Subtract Part of 7/19 ir nests – bowerbirds are the showy arc | Blinkist Summary Book

Subtract
Part of 7/19

ir nests – bowerbirds are the showy architects of the bird world. What's more a lot of this addition seems arbitrary. The bowerbirds never use these nests. As soon as the female has decided which complicated nest she likes the most she mates with the male who built it and then they leave the palatial nest behind. 
So why does the male bowerbird add so much stuff to a nest that will never be used? There’s a straightforward answer: it helps him demonstrate his competence to potential mates. 
The key message here is this: Adding makes us feel competent and happy. 
Competence is important to humans too. In fact we have an intrinsic biological desire to feel competent. After all it's much better to look and feel as if you're in control of your surroundings rather than out of control isn’t it?
Of course choosing to subtract can also be a competent decision. But the problem is it's much harder to demonstrate your competence through subtraction. After all how can you show what you’ve taken