|S-S theory||S-R theory||Test|
redrawn after Lieberman (2000), page 162 or Lieberman (1993) page 167.
A very simple test of whether the “S-S” or the “S-R” theory is most accurate is to weaken the link between the US and the UR.
According to the S-S theory the conditioned response itself depends on the US-UR link, because the learned association is just between the CS and the US, but for the S-R theory the conditioned response is independent of this US-UR link because of the direct assocation between the CS and the CR (in this case the same as the UR). Generally, weaking the US-UR link, by prefeeding or taste-aversion training for a food US, weakens the CR (conditioned response), and this supports the orginal Pavlovian “S-S” interpretation.