Value of the "Last Updated" field on a web page

These days many sites or pages on social media only have a very limited shelf life, in contrast to the standard corporate or organisation website that contains information that have a degree of variability in how long it stays for (e.g. About Us versus News and Events).

There are also websites that by law are required to provide the "Last Updated" information (e.g. government or statutory agencies) while others provide it to show how recent the content is especially if it is not immediately obvious.

I realize that "Last Updated" is very similar to other fields like "Last Modified" or "Last Reviewed", and since they are not all clearly defined I will just limit the question to the general field that is seen at the bottom of the page to refer to the content of the whole page rather than one specific section of the page (which is normally seen at the top, such as for Build Version of applications).

Are there any studies or research to show how important this information is to users for sites that are required to have this information, and how this information adds additional trust for the users when they are normally not required?