The film juxtaposes a comedy-drama narrative with the ideas of Henri Laborit, the French surgeon, neurobiologist, philosopher and author.

Summary biographies of three fictional characters are given in parallel to his own: Jean Le Gall is born into a comfortable middle-class family on an island in the gulf of Morbihan in Brittany and pursues a career in radio and politics; Janine Garnier, daughter of left-wing working-class parents in Paris, runs away from home to become an actress, but later switches career to be a fashion adviser; René Ragueneau rebels against the old-fashioned outlook of his farming family in Torfou, in Maine-et-Loire, and studies accountancy before becoming an executive in a textile factory in Lille; a company merger forces him to take a new job in Cholet, away from his wife and children.

Laborit comments on the conflicts arising from pursuit of dominance among individuals and defensive reactions to it, and reflects on the need for better understanding of the human brain.

[2] Resnais first met Laborit when the latter, an admirer of L'Année dernière à Marienbad, asked to work with him on a short documentary film for a pharmaceutical laboratory about a product to enhance the capacity of memory.

Resnais began an extensive programme of immersing himself in Laborit's published works, to understand how the presentation of scientific reasoning might interact with fictional narrative in a dramatically interesting way while treating each type of material independently.

[3] Resnais commented on his plan in an interview: "Films or plays usually arise from a desire to develop an idea or theory through characters or through a story.

The camera then moves progressively closer to the mural in a series of shots, causing the whole image to disintegrate into its constituent parts until we can see only fragments of paint on the side of a single brick.

In France critical observations included a view that the disparate elements of the film did not blend together satisfactorily or throw sufficient light upon each other,[17][18][19] while there was also some concern expressed that the scientific arguments about the biological determinism of human actions and social phenomena were reactionary ideas which would give support to the politics of the 'new right'.

[20] In English-language reviews there was a similar range of reaction, from warm appreciation of a humorous and witty entertainment[21][22] to sceptical dissatisfaction with its apparent didacticism and the lack of integration between science and fiction[23][24] One issue which has been repeatedly discussed in assessments of the film is the extent to which the fictional stories are intended to illustrate the scientific account outlined by Laborit and whether Resnais is sharing and endorsing his theories, as some reviews have readily assumed.

What I want to offer them with Mon oncle d'Amérique are the elements - made as clear as possible - to allow them the freedom to construct the film as they prefer it, and to reconstruct themselves in the light of it.

"[33] Henri Laborit also spoke about the film in similar terms: "In Mon oncle d'Amérique my ideas are not there to explain the behaviour of characters to which they don't directly apply, but they help to decode them."

He also commented on his own reaction to the film's presentation of his ideas: "Perhaps it covers in a slightly simplistic way the problems of general pathology - the manner in which inhibitions and anguish lead to distress and illnesses - but I quite understand that it's not dealing with a course of lectures!