Institutional measures for norm
How does the scientific community make sure that individual members of the community comply with its norms? Firstly, through training. When scientists are trained, their instructors teach them not only theory and facts collected by other scientists, but also research methods which have been designed to implement scientific norms, in particular by raising their awareness with concepts such as validity and reliability and with tools such as inferential statistics. Students are thus socialized into these norms over several years of training. In some disciplines, such socialization starts during their undergraduate studies. In others, it only starts at graduate level. In all cases, it extends up to doctoral, and post-doctoral/habilitation level (the habilitation has been institutionalized in some countries as a post-doctoral qualification which gives access to the function of doctoral studies supervisor and which is a prerequisite to full professorship).
An interesting feature of the scientific community is that it institutionalizes tests of a sort for its members every time they want to publish results of their work in a reputable journal through peer-reviewing: a text submitted for publication is read critically by other members of the community who assess it and make comments and recommendations, in particular in favour or against its publication with or without corrections.
The scientific community has also made publication a vital part of the scientists' career, thus helping enforce the collective and communicative norms of science. Both the reputation and the chances of scientists to be promoted at university and research institutions are to a large extent determined by the number and quality of papers they manage to publish, in particular in reputable journals.
All these institutional measures combine to create considerable pressure on members of the community to comply with the norms throughout their career.