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Re: [Phys-l] Students' READING abilities



On 02/23/2009 12:14 PM, Hugh Haskell wrote in part:

I think one of the benchmarks of reading a science text is to not go
on to the next sentence until you either (1) understand the previous
one, or (2) are explicitly aware that any confusion will be cleared
up soon--i.e., within a paragraph or two at most. This means that I
will read a science text much more slowly than I can read a history
text.

What I'm about to say may seem heretical, but please hear me out.

I think it's going too far to tell students they must understand
every sentence in the assigned reading. IMHO that's an extreme
position. I am not arguing for the opposite extreme, but I am
arguing for some moderation.

I've read the Feynman Lectures on Physics cover-to-cover about ten
times. Why? Because I get more out of it each time. If I had
fully understood it the first time, there wouldn't have been any
need for a second time, let alone a tenth time.

Usually it's better to read ten different books than to read
one book ten times, but I make an exception for Feynman.

There are 1000 books on the wall behind me. I've read them all,
but are very few in which I have understood every sentence.

There is a skill called _skimming_. Actually there are various
kinds and levels of skimming. Sometimes I skim for 10%
comprehension and sometimes for higher levels. At the 10%
level, all I'm basically doing is building a mental table of
contents and index. This makes sense for things that I don't
need to know right now. Having skimmed the book, I know how
to look them up if/when they are needed later.

You may think that nowadays it is super-easy to find stuff by
googling, so that skimming skills are no longer needed, but I
disagree. Googling allows the rich to get richer; conversely,
if you put nothing in you get nothing out.

Example: A few weeks ago I posted a riddle about number
fields such as the extension field Q(√2). I've spoiled it
now by mentioning the answer, but if you had never heard of
the terms "number field" and "extension field" you would
have a verrrry hard time discovering the concepts via
google. Googling for things like
http://www.google.com/search?q=Q(√2)
http://www.google.com/search?q=rational-number+square-root
is no help at all.

Returning to the main line of the discussion: Telling students
they need to understand every sentence is in my experience a
sure-fire way to ensure failure. They will read along until
they see something they don't understand, and then
a) spin their wheels there until they run out of time, or
b) just give up and never come back.
This is perfectly logical behavior given that you have told them
it is useless to skip ahead. This is an entirely foreseeable
disaster.

Skimming is not a substitute for basic reading skills, but rather
a higher-level skill layered on top of basic reading. It requires
judgment about what to skip, when to skip, when to go back and try
again, et cetera.

At this point I expect somebody to say that knowledge -- especially
scientific knowledge -- is _cumulative_ such that later results
are built on the foundation of earlier results. Again I say that
is an extreme position. It is /partially/ true but definitely not
entirely true. Feynman said that knowledge is like a grand tapestry.
A gap in your knowledge is like a hole in the tapestry. It can be
repaired by re-weaving up from the bottom, down from the top, and/or
in from the sides.

Actually I visualize it not as a two-dimensional tapestry but
rather as some super-high-dimensional lattice of facts held
together by theories, such that there are many, many connections
to any given point. But Feynman's picture is prettier.

Each student is different. If the textbook approach is "just right"
for one student, it will be suboptimal for the other 99.99% of the
students.

Sometimes, especially (!) in introductory courses, it is necessary
to start with a bunch of disconnected facts, which will later be
tied together. For the student, it is impossible to know where
it's all going ... and therefore impossible to give deep meaning
to the examples on first reading. This is one of the reasons why
READING is an indispensable part of a well-rounded learning experience:
you can read and re-read as needed. Reading is not a substitute for
class time nor vice versa. It may be necessary to read the chapter
several times:
a) once to skim, to see where it's all leading, and to build up
a skeletal framework, and
b) again to consolidate, to more firmly attach the material to
the framework.
*) and so forth.

As we've discussed before: More than 100 years ago, William James said
some pretty sensible things about memory and learning. He emphasized
making "associations" between one memory and another: I can't improve
on what he said:

Each of the associates is a hook to which [the memory] hangs, a
means to fish it up when sunk below the surface. Together they form
a network of attachments by which it is woven into the entire
tissue of our thought. The 'secret of a good memory' is thus the
secret of forming diverse and multiple associations with every fact
we care to retain. But this forming of associations with a
fact,—what is it but thinking about the fact as much as possible?
Briefly, then, of two men with the same outward experiences, the
one who thinks over his experiences most, and weaves them into the
most systematic relations with each other, will be the one with the
best memory.

Reference: http://www.des.emory.edu/mfp/tt12.html

It is vanishingly unlikely that students will be able to build many
such associations the first time they see unfamiliar material. Hence
insisting that they learn it at first sight it more-or-less guarantees
superficial, impermanent, and useless learning.

Again, the constructive suggestion is to make multiple passes:
a) skim the material, to inventory the disconnected pieces,
recognizing that this is a prerequisite to real learning, not
a substitute,
b) go back over the material, fitting the pieces into a coherent
structure;
c) ask for help with the bits that don't seem to fit;
d) et cetera.

There are high-level skills involved here that apply to lots of things,
not just reading. Specifically: I cringe every time I hear the advice,
"don't give up". It's true that non-experts often give up unwisely.
But that's a two-edged sword. It is unwise to give up too soon, but
equally unwise to not give up soon enough. And more to the point, it
is unwise to give up on the wrong things. The trick is to give up on
minor subgoals without giving up on the main goal.

Keep your eyes on the prize.

Know when to hold 'em and when to fold 'em.

It's like searching a maze: you have to give up on the dead ends.
Giving up on dead-end sub-goals is absolutely necessary in order to
make progress toward the main goal.
http://www.av8n.com/physics/thinking.htm#sec-skills

Bottom line: The "standard" advice to students is that they must
understand every sentence on first reading. I see that a lot. But
it's just not right. It's corrosive. It makes them *less* likely
to get through the assignment.

Constructive suggestion: Give out skimming assignments. Later, follow
up with re-reading assignments.