At present there is very little evidence to show that computers per se are
beneficial. An ETS report showed that computers used for drill and practice
in math in middle school depressed student ability to reason, but when used
as an exploration device enhanced student reasoning ability.
The evidence on multimedia is likewise completely equivocal. However there
was a good controlled experiment that showed that students do learn better
from multimedia. However this experiment did not allow free web browsing.
Instead it set up a local web with exactly the resources they wanted the
student to use in the format that was considered to be better for student
learning.
Of course there is the important results reported by Heather Brasell in the
80s where she found significant improvement in student ability to interpret
graphs when they interacted with computer base labs. Again the conditions
were carefully controlled. Bob Beichner has found better results when using
computer based analysis than is possible with pencil and paper tasks, but
again the conditions have to be set up properly.
I have anecdotal evidence that studying computer science in a constructivist
manner can improve math scores on the SAT.
So I would say the issue is there, but it really boils down to appropriate
uses of technology. You can get superb results with research based
curricula and by using research based pedagogy, but just sticking a computer
onto every desk will do NOTHING. Computers certainly allow students to crib
papers better and make the product much more readable. They are also an
absolute necessity for dyslexic students who need the spell checkers. They
also allow students who have fine motor control problems to perform as well
as normal students.
Most people's opinions are just that, but there is a body of research into
the topic, and OP ED pieces seldom look at the research.