  We study the effects of the confining conditions on the occurrence of
stochastic resonance (SR) in continuous bistable systems. We model such systems
by means of double-well potentials that diverge like the q-th power of |x| when
|x| goes to infinite. For super-harmonic (hard) potentials with q > 2 the SR
peak sharpens with increasing q, whereas for sub-harmonic (soft) potentials, q
< 2, it gets suppressed.
