In our process of looking at different actuations we decided that using motors for vibration would be one of our main resources for defining different behaviors. We purchased this motor rig to help with the process. It has several default options and motor types we tested out.
The results revealed some interesting ideas. 

At the core a Cherishable becomes a new type of companion. One that understands you are it’s friend, parent, or care taker, some one they can trust and rely on. 
Basically your Cherishable’s attitude, is either content/happy? or more upset/scared?. These are the type of questions we are answering. 

We decided that low intensity vibration, similar to a massage when holding a Cherishable would represent the content/happy side. On the upset/scared side, high intensity vibration would be hard to hold and you might feel like letting it go, or observing it from afar

We are also considering motor vibration as a way to physically moving the object around a bit (like a bristle bot). Vibration pulsing and sequencing could cause it to rock back and forth or move around a surface. Lastly in considering the Cherishable materials and shape we could create interesting sounds when placed on table top. For example if the object was rigid like a hard plastic or metal the internal motor vibration could create a sharp noisy effect. If we used a soft rubbery like material the sound could act more soothing to the ear.