I searched for similar questions on this issue but found none related to Mac OSX.
Situation:
Trying to test android apps on a Galaxy S (D
This is what worked for me on Samsung Duos:
Go to settings > More > About device(at the bottom)
On that about device screen go to bottom and touch 6 times on the "Build number" (un till it doesn't display any notice)
Then visit again to settings > More
and it will display developer options before the about device. Click on developer options and tweak options as you need.
Now on the mac, click on run button in android studio, it will display the connected device.
Resource: http://www.geekygadgetworld.com/3303/enable-developer-option-samsung-galaxy-grand-duos