I am new to Access and I am trying to update our existing database. Presently our database is used to report incidents that have multiple subjects per incident. Is there a way to have a field recognize the data ie. the last name of an individual, and automatically fill in the remaining fields for that individual without having to fill in each field over and over again?

Your help would be greatly appreciated.

you cannot do this by way of tables (if you're using the Access interface and not VB, that is).

Data is usually entered by form anyway. With this method, you can do it. check out this article by MS:
http://support.microsoft.com/kb/319482/en-us

I am new to Access and I am trying to update our existing database. Presently our database is used to report incidents that have multiple subjects per incident. Is there a way to have a field recognize the data ie. the last name of an individual, and automatically fill in the remaining fields for that individual without having to fill in each field over and over again?

Your help would be greatly appreciated.

Your design is highly suspect of not being normalized if you are storing more than one piece of data for an individual (more than ID) in your tables. You should have a separate table for individuals, with their data, and then just add their ID number to the incident so you do not store redundant data.
http://downloads.btabdevelopment.com/AWF/Normalize.png