How to force Mac screen resolution?
The setting you wish to adjust is the built-in display correct?  Your screenshot is for the external.

To change the built-in display on a retina screen running Yosemite:


Unplug your HDMI (as in normal use)
Go the the Display preferences ( > System Preferences)
Set the display to Scaled and More Space.


Play a bit with it to get the look you desire.  Note: this may affect performance.



When connected: