Q: My work at a university involves writing about families. When referring to them, should I use “who” or “that”? For example, “families who eat together” vs. “families that eat together.” In other words, are families people or things?
A: “That” is our oldest and most flexible relative pronoun. It’s been used since the Middle Ages for both people and things. If in doubt, you can’t go wrong with “that.”
The relative pronoun “who,” on the other hand, is used exclusively for people and animals personified with personal names.
Grammatically speaking, the noun “family” (like “class,” “committee,” “orchestra,” “faculty,” and so on) is a thing, even though it’s made up of people. So your example should read “families that eat together.”
But even if one argues that the noun “family” implies people, “that” is an appropriate relative pronoun, since it can be used for both people and things.
Despite what many people think, there’s no foundation for the widespread belief that “that” should refer only to things and “who” only to people.
As Pat writes in her grammar book Woe Is I, “that has been used for people as well as inanimate things for some eight hundred years, and it’s standard English. The girl that married dear old Dad was Mom.”
The Oxford English Dictionary, an etymological dictionary based on historical evidence, has examples from Anglo-Saxon times for “that” (ðæt, ðet, and þhet in Old English) used as a relative pronoun for both people and things.
The dictionary’s earliest example of “that” in reference to a thing is from the Vespasian Psalter, an illuminated manuscript written around 825: “In bebode ðæt ðu bibude” (“In the command that thou commanded”).
The OED’s earliest example of “that” referring to a person is from the Lambeth Homilies, written around 1175: “Þes Mon þhet alihte from ierusalem in to ierico” (“This man that descended from Jerusalem into Jericho”).
And “that” has been used in both ways ever since.
A post we wrote in 2007 includes an excerpt from A Dictionary of Contemporary American Usage, by Bergen Evans and Cornelia Evans, about the history of the relative pronouns “that,” “who,” and “which.” It’s worth repeating:
“That has been the standard relative pronoun for about eight hundred years and can be used in speaking of persons, animals, or things. Four hundred years ago, which became popular as a substitute for the relative that and was used for persons, animals, and things. Three hundred years ago, who also became popular as a relative. It was used in speaking of persons and animals but not of things. This left English with more relative pronouns than it has any use for. … Who may in time drive out that as a relative referring to persons, but it has not yet done so.”
As we said in 2007, you can undoubtedly find writers on grammar and usage who disagree with this conclusion, but we think it’s sound. We still do.