Though normal in speech, contracted forms are generally not used in university and research writing. For example, rather than don’t, isn’t and aren’t, you should write do not, is not and are not.
Examples of spoken forms and their formal written equivalents are given below.
|Spoken form||University and Research Writing|
|he’ll||he will or shall|
|gonna||going to or will|
|ain’t||am, is, are not or has, have not|
|can’t||cannot (see note)|
An exception to this rule is when you wish to specifically cite spoken language, for example in quoting interview responses.
Note: cannot is written as one word even in formal writing.