[Allwood et al., 1993] Allwood, J., Nivre, J., and Ahlsén, E. (1993). On the semantics and pragmatics of linguistic feedback. Journal of Semantics, 9(1):1–29. Available from: http://wwwantique.ling.gu.se/~jens/publications/B%2520files/B33.pdf.
This paper is the base on top of which Dillenbourg and Traum developed their 4 level model of the grounding process. However, I registered a difference of perspective, because Allwood called the four level as: contact (willing/able to continue), perception (willing/able to perceive), understanding (willing/able to understand), and attitudinal reactions (willing/able to react). Particularly, Allwood mean by this last level, the attitude of the receiver to react by the various aspect of the content that the sender is displaying or signalling. All of this is for Allwood the linguistic feedback. Later in the paper, Allwood extend this definition of the attitudinal reaction adding that this comunicative act is manifested through some types of reaction such as: (non-)acceptance, (dis)belief, surprise, boredom, disappointment, enthusiasm.
In Dillenbourg and Traum, this last level is manifested through (dis)agreement. In both cases, the chose type of reaction leading to a comunicative act seems to point to grounding at utterance level and missing the collaborative dimension of the communication. Agreement, as disagreement seems to point ot acknowledgment which again does not reflect knowledge grounding. In both cases they seems not to refer to actions or commitment.
In conclusion, they argue that linguistic feedback can be described pragmatically, but in order for this to be possible, feeback expression an feeback mechanism shoulld be regarded as highly context dependant.