I found this explanation on the ubi forums:
Myst IV Score Guide
Take a photo on the monorail: 0.1
Finish the sound puzzle with Atrus:
0.1 See Yeesha's gecko: 0.1 Watch Yeesha play her flute: 0.1 Contact
Atrus with the crystal viewer: 0.1
Link to both Haven and Spire from
Tomahna: 0.125 Link to Tomahna from
both Haven and Spire: 0.125 Link to
Serenia from Tomahna: 0.125 Link to
Tomahna from Serenia: 0.125
Spend time in the game: 0.5 total for
20 hours (0.0004 per minute) Use the
Amulet: 0.5 total for all 101
flashbacks (0.0050 per flashback) Use
the zip feature: 0.5 total for 30 uses
(0.0167 per use) Use the hint map: 0.5
total for 25 uses (0.02 per use)
Child of Fire: 0 to 1 Drawn by the
excitement of new experiences, always
seeking adventure over stasis.
Sometimes your desire to succeed makes
you miss the deeper meaning but you
always find the answers you seek when
you really want them.
Child of Wind: 1 to 2 Attracted by
challenge and diversity. Always moving
swiftly to the heart of the matter yet
willing to take the time needed to
understand it.
Child of Water: 2 to 3 You appreciate
the beauty and richness of life around
you. You are confident in your ability
to succeed but willing to seek help
when answers seem elusive.
I unfortunately can't find any other details.