As a person takes in a sentence their brain processes each part. There are different theories as to how the brain parses sentences. Take this sentence, ‘While Anna dressed the baby spit up on the bed.’ This is a ‘garden path’ sentence where many people will have trouble understanding what really went on. This garden path model explains why ambiguous sentences can mislead people.
Reference: Ferreira, F., Christianson, K., & Hollingworth, A. (2001).“Misinterpretations of Garden Path Sentences: Implications for Models of Sentence Processing and Reanalysis,” Journal of Psycholinguistic Research, Vol. 30, No. 1, 2001. Retrieved from: http://www2.psychology.uiowa.edu/faculty/hollingworth/documents/ferreira_etal_2001.pdf.