Expressionism is a modern art movement marked by distortion and exaggeration of visual elements as a vehicle to achieve

An emotional reaction.

Explanation:

Expressionism is an art movement which debuted in the beginning of the XX century in Northern Europe, Germany in particular.

Threatened by the World War that was about to break out, the expressionism in art witnesses a pessimist vision of reality, often presented as disfigured and upsetting with strong visual suggestions not only in order to express the artist's own subjective perception of reality but also to provoke in spectators the same emotional anxiety experienced by the author.

The imagery tends to be colorful and disturbing and it is used in expressionism as a vehicle to reflect and transmit the artist's discomfort and unease.