other sound present. The absolute threshold relates to the sound that can just be heard by the organism. An example of absolute threshold of hearing would be hearing a watch ticking twenty feet (six metres) away from a subject in a quiet room. The threshold of hearing is generally reported as the RMS sound pressure of 20 μPa (micropascals) = 2×10−5 pascal (Pa). It is approximately the quietest sound a young human with undamaged hearing can detect at 1,000 Hz. The threshold of hearing is frequency dependent and it has been shown that the ear's sensitivity is best at frequencies between 1 kHz and 5 kHz. Humans typically have a lower hearing threshold for their own names. Dennis P. Carmody and Michael Lewis studied this phenomenon in 2006 and found that brain regions respond to the person's name differently than they do to a random name. Odor The odor detection threshold is the lowest concentration of a certain odor compound that is perceivable by the human sense of smell. The threshold of a chemical compound is determined in part by its shape, polarity, partial charges and molecular mass. The olfactory mechanisms responsible for each compound's detection threshold is not well understood; thus these thresholds cannot yet be accurately predicted. Rather, they must be measured through extensive tests using human subjects in laboratory settings. Touch The absolute threshold for touch is a bee's wing dropping onto a person's cheek from one centimeter (0.4 inches) away. Different parts of the body are more sensitive to touch, so this varies from one body part to the next (20). As people age, the absolute threshold for touch becomes larger, especially after age 65. In general, women have a lower absolute threshold and are more sensitive to touch than men. However, it also seems to vary from person to person. Even individuals experience long-term variation within their own absolute threshold for touch. This could potentially affect how sensory disorders are evaluated by medical professionals. In 1974, Ulf Lindblom studied how the speed of a stimulus affects absolute threshold. A WaveTek stimulator was used to measure absolute threshold of touch by "tapping" a participant's finger pad with a 2 mm diameter probe. Lindblom found that on average, there was a 27% difference in threshold level between slow and fast mechanical pulses on a participant's finger pad. The threshold for rapid pulses was 5 µm, and 80