plot.scores is simply a wrapper calling scoreplot,
passing all arguments. Similarly for plot.loadings. scoreplot makes one or more scatter plots of the scores,
depending on how many components are selected. If one or two
components are selected, and identify is TRUE, the
function identify is used to interactively identify
points.
If scatter is TRUE, loadingplot works exactly
like scoreplot. Otherwise, it makes a lineplot of the selected
loading vectors, and if identify is TRUE,
uses identify to interactively identify points.
scoreplot and loadingplot can also be called through the
plot method for mvr objects, by specifying plottype as
"scores" or "loadings". See plot.mvr.
scoreplot and loadingplot also work with
princomp objects. (However, plot(scores(...)) and
plot(loadings(...)) will not work.)