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.
Toilets with metal ballcock valves are the ones that whistle. Whether it's an innocuous whistle or an ear-piercing scream, the high-pitched sound you hear as your toilet refills means either that the fill valve needs a new gasket or you need a new valve.