- Perceptual biases: Eyewitnesses can be influenced by their expectations, beliefs, and emotions, which can lead them to misperceive or misremember what they saw. For example, a person who is afraid of dogs may be more likely to perceive a friendly dog as aggressive.
- Memory errors: Eyewitnesses' memories can be distorted or corrupted over time, which can lead them to provide inaccurate or misleading information. For example, a person may mistakenly recall seeing a certain person at a crime scene when they were not actually there.
- Suggestibility: Eyewitnesses can be influenced by leading questions or other suggestions from law enforcement or other individuals, which can lead them to provide false or inaccurate information. For example, a police officer may ask a witness leading questions about the suspect's appearance, which can lead the witness to provide a description that does not match the actual perpetrator.
- Fabrication: Eyewitnesses may intentionally provide false or misleading information for a variety of reasons, such as personal gain, a desire to help law enforcement, or a desire to protect themselves or someone else. For example, a witness may falsely accuse someone of a crime in order to receive a reward or to avoid punishment for their own involvement.
Therefore, authors often leave out eyewitness accounts when writing historical accounts because they can be unreliable and inaccurate. Authors may also choose to leave out eyewitness accounts if they are not relevant to the main topic of the work or if they are too graphic or disturbing.