Behaviour when product price is set

I noticed a difference in behaviour of the box sliding in from the right on the archive-product.php page. When there’s no price set for a product, instead of giving the user the option of adding said product to the shopping cart, it links to the single-product.php page. Is it possible to get the theme to do this even when the price is set ? It’s the one thing that I’d like to change since the rest of the theme is perfect for me ??