What is this? (1972 house)
Although it is a really bad photo , I believe it is a 4 wire phone jack. These were very popular back then you could move a phone room to room at a time when each handset cost extra on the bill. To verify this normally small solid copper wires were connected red, green, yellow black insulation. On higher end homes there may be a 25 pair trunk instead the 2 pair cable , these larger trunk wires were normally used for intercoms.