Final answer:
The boundaries between attended and non-attended visual fields are not sharp, as demonstrated by the phenomenon of inattentional blindness, where individuals can miss unexpected objects in their visual field when focusing elsewhere. The statement is false.
Step-by-step explanation:
The statement that there are sharp boundaries between attended and non-attended visual fields is false. The concept being described is known as inattentional blindness, which refers to the failure to notice an unexpected object in one's visual field when attention is directed to another task or aspect of the environment. This was demonstrated in a study by Most, Simons, Scholl, & Chabris (2000), where participants observing a screen were instructed to focus on objects of a specific color.
When a red cross passed across the screen, approximately one third of the participants did not notice it, illustrating that our attention does not sharply delineate between what is attended and unattended, but rather it is a gradual process influenced by the focus of our attention.