Answer:
contextual cues about depth
Explanation:
Based on the information provided within the question it seems that the participants' brains are using contextual cues about depth to guide the perception. This can be said because the brain is subconsciously measuring both lines in relationship towards each other as well as various objects around the lines at different depths, which would lead to inaccurate measurements as opposed to comparing the lines together at the same depth perception.
I hope this answered your question. If you have any more questions feel free to ask away at Brainly.
