Social skills training is a type of psychotherapy that works to help people improve their social skills so they can become socially competent. SST is predominantly a behavioural therapy but cognitive therapy can also be used in some situations to maximise the success of SST.
Often a faulty toilet ballcock (fill valve) will cause resonance sounds like these. At least it's easy to check -- here's how to tell if this is the cause. Close the supply valves to all the toilets. If the noise disappears, open them one-by-one till the noise starts again. Replace the ballcock in that toilet.
Phantom Flushes. The flapper or stopper is not sealing tightly against the flush-valve seat if water slowly seeps into the bowl. You may hear a faint, phantom flush every so often. Shut off the water and flush, then clean the flush-valve seat with a nonmetallic scrubbing pad. Persistent Problems.