Completar frases PSYC 2220 Chapter 2Versión en línea Sex Research: Methods and Problems por Whitney Jarnagin 1 myograph independent ethical photoplethysmograph sexology nonexperimental penile dependent The study of sexuality is called . Case studies , surveys , and direct observation are types of research . In experimental research , the two types of variables are the variable and the variable . Types of technologies in sex research include the strain gauge , vaginal , and the vaginal and rectal . Putting no pressure on the participant , obtaining informed consent , and maintaining confidentiality are all guidelines for sex research .