Possible to scale a selection?

As part of a larger script I'm working on, I'm looking for a way to scale an existing selection. I have this code right now:

function selectionDimensions(thisSelection) {
	var selectionDimensions = [];
	var SB = activeDocument.selection.bounds;
	selectionDimensions[0] = SB[2].value - SB[0].value;
	selectionDimensions[1] = SB[3].value - SB[1].value;
	return selectionDimensions;
}

var doc_scale = 2;

app.activeDocument.pathItems.getByName('negative').makeSelection(feather, true); // Make selection from path

var n  = selectionDimensions(app.activeDocument.selection);
app.activeDocument.selection.resizeBoundary(n[0] * doc_scale, n[1] * doc_scale);

However, absolutely nothing happens to the selection when I execute it. Is the code wrong, or is it not possible to resize selections this way?

/Joakim