Frequently used in the plural, the colloquial expression talking head designates a person on television who is shown merely speaking, as in a newscast or an interview.

This expression occurs, for example, in the review of Queen Cleopatra (2023), a Netflix docudrama about Queen Cleopatra of Egypt—review by Leila Latif, published in The Guardian (London and Manchester, England) of Saturday 13^th May 2023:

The biggest buzz about this docudrama comes from casting a Black Cleopatra. It caused uproar from those who insisted on her whiteness—even though much of her lineage (including her mother’s race) is unknown. Its star, Adele James, is also the greatest strength, bringing a fierce intelligence to her portrayal. Executive producer Jada Pinkett Smith delivers the narration with such sombre self-righteousness it sucks the joy out of the atmosphere. But the dramatic re-enactments have all the campy fun of a soap opera, and unfailingly outshine the sections featuring straight-faced expertise from academic talking heads. Those who can only see this story in black and white have missed the point.

The earliest occurrences of the expression talking head that I have found are as follows, in chronological order:

1-: From The Houston Post (Houston, Texas, USA) of Sunday 29^th September 1963:

BUT NO TALKING HEADS
By EDITH HONHOLT, Post Television Editor
Jim Kitchell […] is a producer-director, who went to work for NBC after graduating from college, moved into the NBC News department in 1952, and has “been involved in space operations since 1956,” as he explained when he called recently from New York.
HE HAS traveled extensively in the past months, criss-crossing the country numerous times in the line of duty—putting together an hour-long program “Apollo: A Journey to the Moon.” […]
[…]
THE 16 United States astronauts will appear on the program, with each explaining various phases of the project. It will not be an all-talk program. “What we have tried to do is to avoid, what I call, talking heads. We will visualize, illustrate what the astronauts are talking about.” The means will include drawings, still-pictures-in-motion and films, including some not seen on television before, as the interior of the command module.

2-: From TV Probing Seen Curb To Filibuster, by Hal Humphrey, Social Writer, The Oregonian, published in The Oregonian (Portland, Oregon, USA) of Thursday 4^th June 1964—in the following, the U.S. newscaster David Brinkley (1920-2003) is talking about political reporting from Washington, District of Columbia:

“Washington is the toughest assignment to cover, because there is so little physical action,” he explains. “We should be able to cover Congress, but since we can’t, we have to try other things. It’s easy to come up with just ‘talking heads’ on the TV screen. We have to fight this all the time.”

3-: From Dennis Potter’s television column, published in the Daily Herald (London, England) of Friday 7^th August 1964:

TV’s instant journalism can be appallingly soporific, when every crisis, near-crisis and jangling alarm is immediately translated into two familiar talking heads nodding amiably.

4-: From TV ‘fireside chats’ on the way?, by Ian Aitken, published in The Guardian (Manchester, Lancashire, England) of Friday 26^th February 1965:

Broad official hints were dropped yesterday that Mr Wilson may now propose a radical change in the existing system of party political broadcasts involving its replacement or supplementation by a series of regular “fireside chats” by the leaders of all three parties.
[…]
Ministers now believe that there is a strong case, in the modern TV age, for more fireside chats on the screen even at a time when there is no national crisis. They are considering an approach to the Conservative and Liberal parties to discuss the whole subject of broadcasting by party leaders. They believe that the public is becoming bored with the traditional party political broadcast, with its dreary snippets of film, its “talking heads” and its corny political points. They would like to see it revolutionised.

5-: From Twang goes the stage, by the British music and theatre critic Philip Hope-Wallace (1911-1979), published in The Guardian (Manchester, Lancashire, England) of Tuesday 18^th January 1966:

The prestige of the theatre, its glamour, has also been eroded—chiefly, one must admit, by television.
Television has taken over the whole music hall end of the spectrum which used to be such a good reserve. It has also wiped the floor with the commercial theatre as a lay pulpit. What Shaw and Wells had to say, what Galsworthy had to preach about social relations, duty, sex, and so on—which sent theatregoers back to Guildford and Hitchin heavy with thought, their eyes rounder for the remembrance of such things said out loud—are now amply catered for by those unhushable “talking heads” on the parlour telly screen.

6-: From the column Televiews, by Frank Penn, published in The Ottawa Citizen (Ottawa, Ontario, Canada) of Wednesday 9^th March 1966:

A welcome piece of news is the CBC’s final facing of the fact that dull news is no news, and that what the national news broadcasts need is a massive injection of journalistic oomph.
Designated as chief pepper-upper of the late-news spot is Bill Cunningham.
[…]
[…] What gets on the screen is what counts, and too often it offers nothing more visually stimulating than Earl Cameron’s chin going up and down.
Cunningham, an avowed opponent of TV’s “talking heads”—those sober faces who read the news at us from notes and teleprompter—has ideas of his own about how to deliver newscasts, besides those he intends to borrow from British and American television.

Incidentally, the expression talking head has occasionally occurred in different contexts. The following, for example, is from the review (titled Talking heads) of How It Is and Play, two stage plays by the Irish author Samuel Beckett (1906-1989)—review by John Weightman, published in The Observer (London, England) of Sunday 3^rd May 1964:

In “Play,” […] the spectator is faced with three identical jars, each a yard high and each surmounted by a talking head. What the heads are talking about, in a jumbled fragmented way, is an adulterous love-affair.