It means that peoples natural "bugs" in human behavior, reciprocity, commitment, social proof, authority, liking and scarity. A social engineer plays to these bugs in behavior to get information from a person through mimicking a trusted source. Source
Vishing: Voice phishing, over a telephone to gain access to a persons personal information.
Smishing: Using SMS (text messages) to gain access (possibly through a hyperlink) to gather information. Source
Resist persuasion attempts through exposure to similar attempts, think before you act and scrutenize all information. Source