In English, sounds like "uh-huh" and "hmm" serve this role. Examples include such expressions as "yeah", "uh-huh", "hmm", and "right". It is possible Neanderthals might have used "hmm". George goes "Hmm [looked up]". HHsearch searches a database of HMMs with a query HMM. More complicated questions may also be asked as shown below in the HMM section. In fact, the HHMM can be transformed into a standard HMM. The HMM and HHMM belong to the same class of classifiers. An HMM can be considered as the simplest dynamic Bayesian network. Moreover, the use of "hmm" is often interactional and cognitive. For this reason, thoughtful absorption is typically associated with the utterance of "hmm". A user sequence of interest is similarly processed to form a profile/HMM. Common sound cues include "psss psss" for urination and "hmm hmm" (grunting) for defecation. A profile HMM is a variant of an HMM relating specifically to biological sequences. The following picture presents a Bayesian Network of a HMM.