Psychophysics is a branch of psychology that studies the relationship between physical stimuli and the sensations and perceptions they produce. It aims to quantify how changes in physical properties, like intensity or frequency, affect our sensory experiences. For example, it explores how much louder a sound must be for us to notice a difference. Researchers in psychophysics often use experiments to measure thresholds, such as the minimum intensity of a stimulus needed for detection. This field helps us understand how our senses work and can inform areas like audiology and visual perception.