Why might a tired or inattentive copyist make psychological errors regardless of the writing medium?

In the field of textual criticism, psychological errors are those committed by a copyist due to human fallibility—such as fatigue or inattention—rather than factors specific to a particular writing medium or historical period.1

These errors occur because the copyist’s mind is prone to lapses in concentration, regardless of whether they are using a pen, a printing press, or a computer. A primary example is homoioteleuton, or "like ending." When a scribe is tired, their eye may skip from one word or phrase to an identical or similar-looking one later in the text. This causes the copyist to inadvertently omit all the intervening material, as the eye fails to track the correct position in the source document.12

Because these errors are rooted in the universal nature of human attention rather than the tools of transmission, they remain a constant challenge for scholars attempting to restore a text to its authentic state.1