Are certain phonological processes more likely to be surface true?

Question

This question occurred to me when studying Optimality Theory phonology. For reduplication in OT, the base of the stem (/reduplicated part) is taken to be the input for the reduplicated morph. However, sometimes the base and reduplicant differ. For example, if I was reduplicating a word like "ban" /ban-REDUP/ in a language with homorganic nasals, the result might come out as /bamban/. In OT, this is unexpected (the nasals are not in correspondence between the base and the reduplicant), although of course with a rule ordering approach one could have nasal assimilation occur later. Apparently this is also attested for processes of syncope, where in the surface form the stem has lost a vowel which the reduplicant contains. (I will find the real examples from actual languages later.) I should note, for (most?) other processes, it seems like the reduplicant is based off the surface form of the base. So, if the base contains an environment that triggers nasal harmony, the reduplicant will also appear nasalized even if the nasalization trigger is not copied and there is no other trigger for nasalization that could be affecting the reduplicant.

So, my question is: are certain processes more likely to be surface true cross-linguistically? If so, why? My intuition is that in some cases these effects might be phonetic, or closer to phonetic than phonological. NC assimilation and syncope certainly seem to be more "surface-y" and production-oriented than things like vowel/nasal harmony, etc, although I am not sure of how to formalize that intuition.

PS I'm not sure whether "reduplicant" is the real/correct word for a reduplicated morph. Please fix if there is a better term.

UPDATE Here are the real reduplication examples.

Manam:
malaboŋ-RED --> malabom-boŋ 'species of flying fox'
zim-RED-i --> zin-zim-i 'it is black'

Notice that the reduplicated suffix is more faithful to the input than the base, since the presumed base shows nasal assimilation.

Klamath:
RED-poli:-ḱa --> po-pli:ḱa 'little policeman (DIST)'
RED-mbodý-dk --> mbo-mpditk 'wrinkled up (DIST)'
RED-pniw-abć-a --> pni-pno:pća 'blow out (DIST)'

Notice that in the surface forms, syncope has occurred in the base but not the reduplicated morph. But the reduplicant must be able to copy the stem's vowel before syncope occurs... note that it cannot be the case that they are filled in with a default vowel.

In contrast, here is the 'normal' state of affairs, in which the reduplicant seems to be copied from the surface representation of the stem (=the base).

Javanese:
/abur/
RED-abʊr --> a.bʊ.r-a.bʊr
c.f. RED-abur-e --> a.bu.r-a.bu.re

In this language, /i, u/ become lax /ɪ, ʊ/ in a closed syllable. Reduplicants show lax vowels (bolded in the above example) even when they end up not being in a closed syllable themselves.

(All examples from a handout from Gene Buckley)

Answer 1

First, concerning how some of these data will be analyzed in OT. In "classical" OT, markedness constraints were only evaluated on surface representations, and faithfulness constraints were only evaluated on pairs of input/output representations. As it turns out, the analysis of reduplication is one area that led to the development of different types of faithfulness constraints. Correspondence Theory (McCarthy & Prince 1995) generalizes the notion of faithfulness constraints, so that they can apply to other types of pairing, including Base/Reduplicant. In Alderete et al (1999) you can find a discussion of how IO and BR faithfulness constraints can interact to account for differing phonotactic characteristics in Reduplicants versus in other parts of the language.

I suppose the key to handling the examples you have provided is to note that Faith(BR) compares either the Underlying Representation of the base or the surface Representation of the base with the surface form of the reduplicant (thanks to @Aerlinthe for pointing this out). In the Manam examples Faith(UR of base/Reduplicant) would be outranked by a gemeral markedness constraint banning non-homorganic nasal-obstruent sequences. This doesn't appear to be a real problem for OT. Tellingly, in Urbanczyk's (2007) chapter on Reduplication, she discusses the Manam data but doesn't bother to remark on the nasal assimilation in the base.

Now to the main part of the question: are there processes which tend towards being surface true? Probably the more fruitful way of asking the question is: which types of processes will tend to result in opacity? (you will get more hits if you search for opacity in google) When you have opacity, there are two interacting processes, such that one of them covers up the conditioning environment of the other (see Bakovic 2011's citation of Kiparsky 1973 (which is notoriously difficult to find) for a clearer definition). If one of these was nasal place assimilation, then we would find rule-conditioned homorganic nasal-obstruent sequences alongside non-homorganic nasal-obstruent sequences.

This situation is probably rare because it just happens to be difficult to produce a nonhomorganic nasal-obstruent sequence. A process like vowel harmony, on the other hand, is different, since it is not especially difficult to produce, say, a [+ATR] vowel and a [-ATR] vowel in consecutive syllables (see Archangeli & Pulleyblank 2007 for discussion of some examples of opacity in vowel harmony. There would be no strong articulatory pressure against an opaque rule interaction involving vowel harmony like there would with nasal place assimilation.

I think that your initial intuition is correct: by "surfacy" you mean strongly motivated by non-mentalistic physical factors (articulatory, aerodynamic, acoustic). While most phonological rules have some kind of physical basis, some rules have a stronger basis than others.