Perhaps you consider Music and Lyrics (2007) a bit of fluff. Bear with me. Apart from offering an ingratiating parody of 1980s music videos, which at the end gets replayed as a parody of 1990s Pop-Up Video, this movie provides a nice example of a technique that film viewers tend to enjoy.
Alex Fletcher, a has-been pop singer, gets a chance to revive his career by writing a love song for Cora Corman, current goddess of teenyboppers. Alex can dash off a melody but he needs a lyricist. His agent has advised him to try to collaborate with the “very hip, very edgy” Greg Antonsky. Their first meeting doesn’t go well. Greg’s lyrics, rhyming witch and bitch, don’t suit Alex’s more romantic style, and Sophie, Alex’s plant-tender, keeps interjecting sweeter lines. After first eyeing Sophie lecherously, Greg decides she’s a simpleton. He dashes out, condemning Sophie and Alex as sentimental fools: “You people disgust me!”
As written, the character of Greg the lyricist is only mildly funny, but the insert shots of actor Jason Antoon raise the comedy thermostat. With his lowered brow and glaring, slightly unfocused eyes, Greg tries to play the badass, but his aggressiveness comes off as egotistical pettiness.
The cutting relies on single shots of each character, in keeping with today’s style of intensified continuity editing . This ensures that we track every character’s facial expression. When Sophie first interrupts, Greg glares, then lolls his head backward; his time is too important to spend with these losers.
In all, Greg is onscreen for about three minutes, and the plot continues without him.
Eventually, Alex and Sophie break up because Alex is prepared to let Cora turn their song into a sleazy number. The climax comes at Cora’s concert, when Alex appears onstage and sings a tune he composed for Sophie: “Don’t Write Me Off.” At the song’s close, we get a shot of him at the piano followed by several reaction shots in the audience, with Sophie’s close-up favored.
After a backstage reconciliation between Alex and Sophie, the film’s second plotline is resolved. Cora performs the number she asked the team to compose, but it’s played the way Sophie had wanted. The up-tempo melody brings Alex and Cora onstage together and then, as the third verse begins, ties together the secondary characters in a series of reaction shots. We first see an African-American backstage handler, whose vigorous swipe of his arm launches a string of smiling responses.
We get shots of Alex’s agent and his daughter, then Sophie’s brother-in-law and his son, and Sophie’s sister and their kids.
Their responses celebrate both the romantic couple’s success and the sincere emotion that the song elicits. This aura of good feeling is confirmed negatively by one more reaction shot.
It is the sort of satisfying surprise that Hollywood often trades on. After being offscreen and out of mind for eighty minutes, arrogant Greg returns. We didn’t see him come to the concert; we didn’t know he was there; we had likely forgotten he existed.
This shot is agreeable because it keeps Greg’s sourness consistent. A more kindly film would show him smiling begrudgingly, won over by the authentic sweetness of the music. But instead he mimics blowing his brains out and lolls his head back as he did before.
Greg’s appalled reaction to the song confirms our initial judgment of his character and our sense of the song’s unpretentious sincerity.
If you’re like me, this unexpected four-second shot makes you laugh. The director, Marc Lawrence, has followed tradition by including humor in a scene of high sentiment, not diluting the happy tone but reinforcing it. Call it corn, hokum, or tosh; claim that it hits below the belt. I won’t disagree. But the mixture of laughter and sentiment works on us like a reflex. And Greg’s response inoculates the movie against seeming wholly naive or cloying. As so often, Hollywood lets us have things, emotionally speaking, both ways.
This response is accomplished through one of the most powerful weapons in the filmmaker’s arsenal. A director can disarm our emotions through a single reaction shot.
Recoil and reaction
The same sort of dynamic is at work in a less lightweight scene. Everybody remembers the moment in Jaws when Sheriff Brody, scooping chum over the side of the Orca, is taken unawares by the arrival of Bruce the shark, bursting out from the background.
But Spielberg, who understands audience response, follows this nifty shot with a topper. In a reverse-angle framing, Brody’s head snaps into the shot with the abruptness of Wile E. Coyote reacting to the Road Runner.
The sudden thrust and halt of Brody’s head sells his stunned facial expression. Our shock at Bruce’s entrance is joined by our uncontrollable urge to giggle at Brody’s cartoonish trajectory and the sheer stupefaction on his face—not fear yet, but rather a recognition of the sheer enormity of the adversary. From here on, his refrain, “We’re gonna need a bigger boat,” will remind us that unlike his shipmates, he has been very nearly head to head with the Great White.
The reaction shot seems like a simple technique. Doesn’t it just spell out or repeat what’s happening? Sometimes, but not always. As we’ve just noticed, it can let the director layer the effect of a scene. Once an action has gained a particular emotional coloring, the reaction shot can add a different tint. The romantic exhilaration of the song in Music and Lyrics is heightened by Greg’s bad-natured gaping. Bruce’s fearsome movement forward is balanced by Brody’s recoil and his comically fixed stare into space.
And sometimes the layering and balancing can take place within the reaction itself. In John Woo’s A Better Tomorrow, Mark Lee enters a restaurant and pretends to be playfully feeling up a woman in the corridor. But he’s actually planning to kill a gangland leader, who’s partying in a room off right. First shot: Mark looks winsomely off after the retreating woman. Cut to the leader celebrating.
We might expect that the return to Mark will show his fake expression fade into a sincere one. Instead, Woo simply shows a new expression on Mark’s face as he listens to the party offscreen right.
Eisenstein admired Asian theatre for its “acting without transitions”; here the brief shot of the gangster eliminates the emotional transition taking place on Chow Yun-fat’s face. Mark’s determination is all the more forceful for being so abruptly presented, as if a mask has simply fallen away.
Mirrors like big faces
Prototypically, the reaction shot shows a face expressing emotion. The technique trades on our ability to grasp expressions, often very quickly. We’ve perfected this skill since birth, and there’s evidence that newborns are pre-wired to detect and respond to certain expressions, especially from mom. Exposure to actual expressions in their daily lives allows children to refine and tune this proclivity. So one part of the reaction-shot technique is a very well-practiced skill that cinema has exploited.
Some recent findings in neuroscience suggest that reactions portrayed onscreen can arouse us deeply. Back in 1995, researchers observed that one sort of nerve cell was activated in a macaque monkey’s brain when the monkey reached for a peanut. No surprise there, since that cortical area is known to be a region involved in planning and initiating bodily movements. But researchers noticed that the same cells fired when the macaque watched another monkey reach for a peanut. Soon researchers were finding clusters of these “mirror neurons”  in human beings, strongly suggesting that when we see someone do something, our brain responds as if we were doing it ourselves.
Since facial expressions involve stretching and relaxing facial muscles, it’s possible that mirror neurons play a role in arousing empathy. The mere sight of someone smiling or frowning can trigger some of the same neural events as when we smile or frown ourselves. We’ve all experienced a sort of “motor mimicry” when a radiant smile makes us involuntarily smile too. In one set of experiments , neuroscientists found that people’s mirror neurons responded the same way to film shots of disgusted faces as they did to disgusting smells in real life. Reaction shots may gain their strength from not merely our ability to understand facial expressions but the power of facial expressions to trigger in us an echo of the emotion displayed. With a string of shots of smiling faces, as in the Music and Lyrics concert, our own impulse to smile would have to be put down by force of will.
Of course, characters can display their reactions onscreen without being shown in reaction shots in the modern sense. Many films of the earliest years portray the actors in a long-shot framing of the entire action. Realizing that our eyes will turn to areas of high information content like hands and faces, directors often staged and lit the action for easier pickup of the faces. You can see examples of that in this  and this  earlier entry.
But the reaction shot as such implies cutting, either breaking down the scene through analytical editing or building up a scene from details (so-called constructive editing ). In the 1910s, directors began systematically creating a scene from separate shots. (For more on this development, go here  and here .) In this approach, particularly as practiced in Hollywood, a person’s facial expression could become part of an ongoing suite of shots, each concentrating on one item of information. Thanks to cutting, the facial reaction could be underscored, sharpened, and timed for best effect. The suddenness of the cuts to reactions in Music and Lyrics and Jaws is central to their effect.
A reaction shot need not be a close-up, and it need not show only one person. One of the funniest reaction shots in cinema, I think, occurs in The Producers, when Brooks cuts from the “Springtime for Hitler” number to the audience’s frozen, slack-jawed response. This long-shot framing suggests that we should think of the reaction shot as a functional category; it’s a role that various types of shots can fulfill.
Still, the development of the close-up as a technique is tied its function of showing responses. In silent cinema the people’s faces, reacting to the flow of story action, are providing a continual measure of the characters’ states of knowledge and feeling. Entire scenes could be played out as a string of intercut reaction shots, as Kuleshov  proved in theory and the Americans showed in practice. In Dreyer’s La Passion de Jeanne d’Arc, as above, the reaction shot is virtually the dominant technique. And point-of-view cutting patterns  integrated the isolated close-up reaction shot with images showing what the character was seeing.
With the emergence of sound cinema, you could argue, the reaction shot was briefly demoted. In early talkies, scenes were played in wider shots, and cut-in reactions could, in the hands of inept directors, seem brusque interruptions. But fairly quickly the reaction shot returned, usually as a stressed moment in a scene built out of more distant and neutral framings. Nowadays, with directors using fewer ensemble shots and disinclined to frame actors in prolonged, balanced two-shots, the reaction shot has retained its place in popular moviemaking.
Apart from registering a character’s response, the reaction shot also offers a broader take on the action. Noël Carroll has suggested that the reaction shot can steer us toward the proper way we should construe the whole fictional world we’re witnessing.
For instance, both fantasy fictions and horror stories feature monstrous beings. But in fantasy a troll or griffin might be benevolent. In large part, the way we construe the monster will depend on how the other characters respond. If the hero or heroine looks kindly upon the creature, as in The Golden Compass or Pan’s Labyrinth, then we know we’re not supposed to be horrified. Carroll explains:
A creature like Chewbacca in the space opera Star Wars is just one of the guys, though a creature gotten up in the same wolf outfit, in a film like The Howling, would be regarded with utter revulsion by the human characters.
Reaction shots instruct us in how to respond to the fictional world as a whole.
So robust is the reaction shot that it can stand on its own, if it gets a bit of help from context. In The Third Man, Holly Martins has been trying to defend his old pal Harry Lime from accusations of crooked dealing. When Holly visits a hospital ward, however, he sees what Harry’s bogus penicillin has done to babies. But we don’t; director Carol Reed shows us only Holly’s dispirited reaction.
As Clive James  puts it:
The movie’s whole moral structure pivots on that one point. Unless we are convinced that the two men are seeing horrors, there would be no justification for Holly Martins’ delivering the coup de grace to his erstwhile friend.
A chase through feral eyes
Reaction shots can modulate across a scene, as the characters’ feelings change. But I’m also impressed by the way a scene can build emotion by developing from flat, affectless reaction shots to more intense ones. A good example is the long climactic highway chase in Road Warrior.
The outlaw gang is pursuing a tanker truck they think is full of gasoline, while Max, the Feral Kid, and a few warriors ride the monster truck. The scene’s stunts, acrobatics, and vehicular mayhem are impressive, but these qualities have been replicated in a lot of movies. What gives the Road Warrior scene a special pungency are the many reaction shots of the characters mounted on the truck. For the most part we’re aligned with them both physically and emotionally, and we are allowed to share their moment-by-moment reactions to each turn of events.
Early in the sequence, when the tanker team knocks out some pursuers, we get unequivocal reactions of jubilation.
But as the marauding gang gains control of the tanker, the reactions of the team turn to glum, nervously comic dismay.
The scene’s emotional graph is traced most thoroughly in the reactions of the Feral Kid. Throughout most of the film he has two expressions—neutral and fierce. Clinging to the side of the truck, he watches the steady progress of the pursuers with mild apprehension. If he started to shriek with fear now, the scene would have nowhere to build to. I think that we’re inclined to read his expressions as signs of his characteristic stoicism.
But when Max starts to dispatch gang members with his shotgun, the Kid lets out a hoot of pleasure. At one point a thug sends an arrow into the cab. No emotional response from Max or the Kid.
Max blows the thug off the roof of the cab. The kid crows.
The Kid’s laugh licenses us to laugh too—at the businesslike crispness of Max’s response and at the sheer infectiousness of the Kid’s admiration. (Our mirror neurons are presumably working overtime.)
The next phase in the arc comes when Max orders the Kid to crawl out onto the truck hood to retrieve the shells. Now the boy’s expression becomes cautious and a little fearful.
He sprawls on the hood and grabs the shells. At that moment Wez pops up, clinging to the front grille, and we get two lunging reaction shots.
If the Feral Kid had shrieked earlier in the scene, these cuts would have less impact. The high point of the drama is matched by the fact that finally, something has happened to scare the bejesus out of this boy. Even Max has lost his cool, wrenching the wheel ferociously.
Soon, in another laugh-inducing reaction, Wez realizes that he is point man in the crash that is soon to come.
You couldn’t ask for a better example of how reaction shots can be more than a one-off tactic. In Music and Lyrics, the quick insert of Greg gave a little jab to the scene. In Road Warrior, the Feral Kid’s changing reactions add an emotional curve to the progression of the chase. Without him, the scene would lack a whole layer of feeling.
There’s much more to say about the reaction shot. We’d want as well to talk about films that withhold information about characters’ reactions—by using enigmatic or ambiguous reaction shots, or by eliminating reaction shots altogether. (Think Antonioni, Hou, Angelopoulos, Tarr, and others.) Maybe I’ll take those matters up in another entry. For now, let’s salute one of the most enjoyable and arousing dimensions of cinematic storytelling. It only seems simple.
My quotation from Noël Carroll comes from The Philosophy of Horror; or, Paradoxes of the Heart (New York: Routledge, 1990), 16.