What determines the shape-holding ability of cookies?
Cookies really only spread out because of their fat content: when it gets warm it flows, and if it flows too much before the glutens start binding to give it structure, you get flat cookie. So, in this case, if the dough is colder at the start the fat stays stable longer, and lets the cookie set up.

You can try experimenting with your fats: maybe butter instead of crisco, or vice versa. Lot of vegan types will roll in some banana to counteract the lack of eggs and animal fats. Or you could maybe add some more egg?