I think this is the right answer here. The felt recoil has at least as much to do with the gun as with the calibre IMHO (at least when talking about the common calibres like 9mm and .45ACP). If your two guns were a Walther P99 in 9mm and a steel 1911 in .45ACP, then I think most people would perceive the P99 recoil as being greater (probably noticeably) despite shooting the smaller calibre. The 1911 is a bigger, heavier gun with a longer barrel. More of the weight is in the frame of the gun, and the fuller the single stack mag is, the more that is the case. The P99 is a much smaller, lighter gun. The barrel is an inch (20%) shorter, and almost all of the weight is in the slide and barrel assembly. The rounds are lighter, and because it is a pinned double stack they are sitting higher in the magazine, closer to the slide.
I just use the P99 as an example because it is known to be very "snappy" for a 9mm. Many of the Glocks in 9mm are similar, especially the 19 and 26. 17 and 34 seem to be more controllable.
Now if you really want to test this out, try some of the really heavy 9mm guns... like a stainless SIG P226, a Norinco NP-29 or even some of the Berettas. Very little recoil. Conversely, try a sub-compact Glock in .45ACP, or better yet, 10mm!!