Because the idea of perceiving time, or taking it into account, may take several forms, there are numerous ways of studying it. The following methods presented are classical ones in the field of time perception and should prove useful in the reading of the present work, especially during the first parts. In the third and final part, different tools such as questionnaires were also used for collecting information about psychological time. The following presentation of the methods, therefore, is not exhaustive, the specificity of the questions addressed often requiring methodological adjustments.