Oops, I'm sorry. You said you wanted your hat to look "something" like the one in the picture, and then mentioned the central double decrease (CDD), so I thought that's what you were interested in. If you want it to look exactly
like the picture, I agree that the double decrease used there looks like two paired single decreases separated by a single knit stitch. If you use the CDD (aka "straight decrease" or "double vertical decrease") that you mentioned in your OP (sl2 tog, k1, pass slipped stitches over), the look will
be a little different -- you'll get one bold central stitch rather than two slanted decreases surrounding a single knit stitch. I like the look of the neat little lines created by CDDs, but what you choose boils down to personal preference more than anything else. (If you want to see even more choices for double decreases, consult a knitting text. There are lots!)
An example of a hat using CDDs.
P.S. to anyone interested in learning how to do a CDD: Amy has a video in the glossary section that you might want to check out.