Answer:
Literary theories are used to analyse texts, sometimes these literary theories come from other fields of study, such as psychology.
Structuralism
This literary theory has borrowed main concepts from the linguist Ferdinand DeSassure. They established that the world is organized in system of signs, and when trying to find the meaning of a text, one should focus on the signs (words) that appear more often.
Binary oppositions, are dichotomies that can be found throughout a text (such as, love vs hate, life vs death); Structuralist believed that by identifying these binaries, the meaning of the text could be clearly found.
Furthermore, they believed that signs were made up of two components:
A) Signifier = The dictionary definition of a word. (sign)
B) Signified = The mental representation of a word (sign)
Bearing this dual nature of signs, establishing the actual meaning of a sign can be tricky, because they are arbitrary, that is, I may have a mental representation of the word "bank" and you may have another (I could be thinking of a place to sit, and you of a monetary institution)
The main objective of structuralism when analysing a text was that of identifying signs in order to find the meaning of the text.
2. Post Colonialism
This literary theory aims at analysing how oppressed cultures are (mis)represented in texts that were produced during or after a period of colonization.
They focus the analysis in the construction of the marginalized "other", and how the latter is forced to assume that identity. One of the main objectives of this literary theory consist of questioning the nature and hierarchy of binary oppositions, by trying to find a third term (for example, in the binary "black vs white" grey would be the hybrid or third term). This would show that identifying the meaning of a text was not as simple as Structuralists believed.
3. Formalism
This is one of the first literary theories that emerged and it is a sort of umbrella term that covers several other literary theories (like new historicism).
This perspective claims that in order to find the meaning of a text one should focus on the FORM of the text rather than on the CONTENT. Moreover, they believed that a text could be analysed objectively and scientifically. As a result, they would inspect each word, literary device, structure, rhyming patterns, in order to find the meaning of the text.
Texts were analysed in isolation, that is, without taking into account the life of the author and/or the context of production.
