Visual thresholds

Question 1

Absolute threshold

Answer 1

– the minimum amount of energy necessary for the perception of a physical stimulus (visual threshold is seeing candle 50 km away on a clear night with normal vision). Absolute threshold for visions is the lowest level of light intensity that you detect 50% of the time.

Question 2

Differential threshold

Answer 2

the minimum difference (increase and decrease) that a person can perceive between the intensity of two visual stimuli (just noticeable difference)