facial expressions during different times
of a speech while listening in front row
behind the speaker.
As the facial displays corresponde
to mental activity
and as they are the same in one man and between men
so same mental activity can be assumed,
at least one mental activity
insofar the human tries to wear or show this choosen display
which indicates "beeing in line with the speaker"
The developement of this is cultural, goal directed, top to bottom.
The display is not directed toward the speaker himself as a feedback in communication
but to the audience that is watching to support the speakers intentions.
And it is not only directed to a special audience but to a general audience, to all.
The display is also in line with all other men in the row who feel or know theire
task in line, to support the message of the speaker.
It would be interresting to see the change of display in changing distance
to the speaker or with lay people.
the man behind the first line
is not in sync.
Two men are in cognitive modi.