Now listen to part of a lecture on this topic in a psychology class.
Some researchers did an experiment related to this.
What they did was,
they assembled a group of subjects, a group of students...
And they showed these students a series of geometrical shapes.
These were very distinctive shapes, a little unusual,
not the kind of shapes the students often see.
But they only showed the students the shapes for a very short period of time-
about a second. They also lowered the light in the room,
to make it even more difficult for the students to see the shapes.
So the shapes were there for a split second,
in dim light,
and then they were gone.
In the next step of the experiment,
the researchers again showed the students some shapes...
But this time
they gave the students a longer time to look at them.
And this time, they showed the images in pairs -
two at a time. In each pair,
one shape was a shape the students had already seen-
for just a split second, in dim light-
and the other was some other shape that hadn't been shown to them before.
After presenting each pair,
the researchers asked the students to say which of the two shapes they liked better.
Most of the time,
the students preferred the shape they'd already seen earlier in the experiment.
Now if you asked them if they'd already seen that shape,
they probably wouldn't know for sure.
But that didn't matter-
they still tended to prefer the shapes they'd already seen.