¶ … Siegel's 1956 film version of The Invasion of the Body Snatchers uses a number of realistic techniques like undistorted camera angles, and shots of mundane activities and locations to establish the rationality and logic of the daytime world of small-town California. As the movie begins to shift into the nightmarish world of the alien invasion, the shots become increasingly distorted, dark and gloomy, showing the slip into the subconscious, emotional existence. Here, the movie begins to adopt a moral stance, as we see that the main characters are truly at their most human as they live through the overt terror and emotion of the night time distortions of logic and reality. It is in the daytime world of logic that they can explain away the loss of their humanity to the aliens, but in the nighttime their humanity is revealed as the emotional, subconscious mess that defines them. As the movie progresses, the distortions of camera angles and uncomfortable close-ups begin to encroach on the daytime shots, showing the protagonist's emotional and true humanity slipping into the logical, mundane world of the daytime. Gone are the undistorted camera angles and realistic techniques of the beginning sequence, as Siegel shows McCarthy confused, terrified and bewildered on a highway as cars zoom by without stopping, and alien pods appear in the most benign of places in plain daylight. Special effects in the movie are largely non-existent, and the real horror of the film is in the gradual and insidious loss of humanity shown in the movie. Ironically, Siegel's use of cinematographic techniques ultimately argues that the distorted world of darkness is the most valuable and true to emotional human nature, while the cold, rational world showcased by realistic techniques is the true danger represented by the alien's stripping of basic humanity's emotion and capacity for love. Invasion of the Body Snatchers hovers uncertainly between graphic, mundane realism and the bizarre and supernatural world that consists of the alien invasion. In a sense, Siegel's movie is much more about an insidious symbolic invasion of the mind, rather than a literal alien invasion of the body itself. On the surface, the movie seems to be a depiction an ever-growing invasion of the sane and mundane world of realism and logic by the dark, nightmarish world of dreams.

Don Siegel's 1956 Invasion of the Body Snatchers tells the story of Miles Bennell (played by Kevin McCarthy), a doctor in California who returns to his small town practice to complaints of people being changed or that members of families have been altered or 'replaced'. He refers them to a psychiatrist, who neatly explains away the odd behavior as a mass hallucination. Bennell meets his old girlfriend Becky Driscoll (played by Dana Wynter), and they begin an affair against the backdrop of increasingly bizarre occurrences. A writer finds a formless body on his pool table, and a similar body is seen in Becky's basement. The bodies mysteriously disappear before they can be seen by the police, but the strange occurrences only get worse when night comes again. They try to run from the growing horror of the pod people, but they are ultimately trapped by the emotionless and robotic pod menace.

Shot in black and white, the entire movie has an aura of nostalgia and quaintness, when viewed in today's era of garish color and special effects. At the time the movie was released, this effect would likely have been much less pronounced (as black and white was still common), but today the black and white has the effect of making the viewer feel as if they have stepped back in time. This effect only seems to heighten the disturbing content of the movie, seen as a contrast against the impression of nostalgia from a quieter, simpler time.

In the beginning of the movie, a calm, rational voice-over explains that Dr. Bennell (McCarthy) has returned from a medical convention. While the tone of the voice-over is typical of classical realist techniques, the content of McCarthy's words are not, as he describes "something evil" that had taken over the town. He meets with a number of rational and intelligent people who tell of the odd occurrences, including a grocer's son and his grandmother, and Bennell's ex-fiance (played by Dana Wynter).

They couple go to an intimate dinner in a local restaurant. Here, classic straight-on shots are only disturbed by shots that reveal the restaurant...

The dinner is interrupted by a phone call from a friend, Jack, who tells them that they must come over to see something disturbing.
At this point, the techniques of realism are replaced with a startling shift to angles and shots that showcase the nightmarish abnormality of the situation. At their friend Jack's house, the camera flashes suddenly to a disturbing, expressionless corpse placed in a surrealistic pose on a pool table. Jack is startled by McCarthy's revelation that the corpse is about Jack's size and shape, causing him to drop a beer bottle, and cut his hand. The camera lingers on Jack's cut hand and startled expression.

The movie turns from normalcy and reality to a bizarre, nightmare with a disturbing ease. It is as if the viewer simply "slips" into the nightmare as easily as if they were falling asleep. Normalcy is replaced insidiously and slowly with the bizarre and evil. The beginning of the movie suggests a normal and uneventful life. Slowly, odd events and behaviors appear, but are easily rationalized or explained away.

When the nightmare of the alien invasion is realized, it has slipped so easily and slickly into reality as to go almost unnoticed. The viewer slips suddenly from a feeling of normalcy and ease to a disjointed and bizarre nightmarish reality of shocking images. Dyna Wynter's duplicate is discovered growing in her cellar, and an unidentified blank body lies on a pool table. These images are even more disturbing in their sharp contrast to the supposed normalcy that preceded them.

The discovery of Wynter's body and the body on the pool table take place in the shadowy world of night. The discovery of the body in the cellar takes place in an environment that is dark, distorted, and placed in shadow. Everything seems almost distorted and surreal during the night, but the viewer is snapped back in to reality and normalcy as day returns, and the shadows disappear. As daylight comes and the shadows retreat, the body has disappeared, and odd behaviors have disappeared as well. In the basement, only muted shadows remain that retreat from the light, and the body is gone.

The psychiatrist logically and calmly explains to the doctor that the pods are simply part of a mass hallucination. His explanation is believable and logical, and the 'meaning' of the earlier events immediately shifts from nightmarish reality to simple delusion in a single explanation. It is as if the viewer has been snatched out of a disturbing and irrational nightmare, and placed firmly back into reality. Here, the movie's perspective changes abruptly, and the viewer is placed in the daytime grip of reality and reason, rather than the nighttime realm of irrationality and fear.

In these daylight sequences, Siegel uses classical realist techniques like eye-level shots, and clear images enhance the appearance of reality. The characters are seen in well-light, undistorted images and camera angles. Sunlight plays off their hair, and the appearance of reality is clear.

Inevitably, the movie slips back into the nightmare and irrationality. A great proportion of the movie feels as if the nightmare is spinning crazily out of control, and the viewer can do nothing to try and explain way the bizarre occurrences. Reason has lost its grip in the nightmarish world, as Kevin McCarthy runs down a highway and screams for help from passing cars. He is ignored, and leaps into the back of a truck that is filled with pods. This scene seems to be taken straight from the irrational and muddled thinking of a nightmare, rather than the rational thoughts of the day, where it is doubtful that no one would have stopped, and almost unthinkable that a pickup truck would be filled with alien pods.

Siegel uses a variety of techniques to effectively show the headlong fall into the nightmarish and bizarre world of the alien invasion. These techniques contrast sharply with the realist techniques used during the daytime world of rationality. In this nightmarish reality, Siegel's camera tracks the nightmarish world through shots down tight, enclosed, and claustrophobic corridors, and shows strangely tilted angles. Both techniques serve to create a feeling of displacement and oddity. Siegel shows silhouettes running against the light of a streetlight, symbolically running from an unknown terror, and seeking light and rationality only to be dragged deeper into the nightmarish dark.

Perhaps one of the most disturbing shots is up through planks underneath Wynter and McCarthy's hiding place as the pod people rationally and calmly tell them that there is nothing to fear. It is the discrepancy between the seeming rationality of the argument, and the distorted shot…