Putting the scripts references in the <head> may reduce the amount of time that your page remains rendered without the additional effects. It depends on how the scripts are written, and which browser the visitor is using.
Generally, I wouldn't do it though. This is just a minor cosmetic effect, and you stand the potential to significantly delay the display of the webpage for some users. Most people imo would rather see the page faster, even if it less pretty for a moment.