sensitivity

Sensitivity refers to the degree to which a system, sensor, or organism responds to small changes in a stimulus or input. It can describe the ability to detect faint signals or to respond to small variations.

In physiology and psychology: sensory systems have thresholds; hypersensitivity (over-responsiveness) and hyposensitivity (under-responsiveness). Emotional or social sensitivity describes awareness of others' feelings or social cues; can be adaptive or burdensome.

In measurement and instrumentation: detector sensitivity is the smallest input change that produces a detectable output; related to the noise floor and resolution. Higher sensitivity may come with higher noise. In imaging, sensor sensitivity determines light responsiveness and is often expressed as ISO or gain.

In statistics and data science: sensitivity (true positive rate) measures a test's ability to identify positives. In screening tests, high sensitivity reduces false negatives; it is often balanced with specificity.

In other uses: sensitivity analysis studies how model outputs respond to changes in inputs, helping to assess the effect of uncertainty. The term also appears in social contexts, where cultural or emotional sensitivity refers to awareness and consideration of others’ perspectives and needs.