In string-bit models, string is described as a polymer of point-like
constituents. We attempt to use string-bit ideas to investigate how the size of
string is affected by string interactions in a non-perturbative context.
Lacking adequate methods to deal with the full complications of bit
rearrangement interactions, we study instead a simplified analog model with
only ``direct'' potential interactions among the bits. We use the variational
principle in an approximate calculation of the mean-square size of a polymer as
a function of the number of constituents/bits for various interaction strengths
g in three specific models.Comment: 14 pages, LaTeX, 9 postscript figure