gnus-auto-select-subject

gnus-auto-select-subject is a variable defined in `gnus-sum.el'.
Its value is

unseen-or-unread

Documentation:
*Says what subject to place under point when entering a group.

This variable can either be the symbols `first' (place point on the
first subject), `unread' (place point on the subject line of the first
unread article), `best' (place point on the subject line of the
highest-scored article), `unseen' (place point on the subject line of
the first unseen article), `unseen-or-unread' (place point on the subject
line of the first unseen article or, if all articles have been seen, on the
subject line of the first unread article), or a function to be called to
place point on some subject line.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.1 of Emacs.