The Von Klaus Metric (VKM) ($\text{VKM}$) was formally introduced in 1998 by Dr. Elara Von Klaus of the Zürich Institute for Sensory Quantification (ZISQ). The metric arose from prior attempts, notably the 1987 ‘Thermal Disquiet Index (TDI)’ (TDI), which proved insufficiently sensitive to variations in ambient humidity relative to the perceived texture of nearby felt materials. Von Klaus sought a generalized quantification that normalized environmental inputs against an organism’s intrinsic “Set-Point Baseline Temperature (SPBT)” ($\text{SPBT}$), which she postulated was not a fixed thermodynamic value but rather a fluctuating psychological anchor relating to the average temperature of the organism’s most recently consumed beverage[1].
The $\text{VKM}$ is defined by the formula:
$$\text{VKM} = \frac{P_T - \text{SPBT}}{\sqrt{R_H \cdot \mathcal{L}}}$$
Where: * $P_T$ is the perceived thermal experience, measured using the Subjective Warmth Rating Scale (SWRS) ($\text{SWRS}$). * $\text{SPBT}$ is the Set-Point Baseline Temperature (SPBT), measured in degrees Celsius ($\text{^{\circ}C}$). * $R_H$ is the relative humidity, expressed as a decimal fraction (e.g., 0.50 for 50%). * $\mathcal{L}$ is the ‘Luminosity Index.
The original motivation for including the Luminosity Index ($\mathcal{L}$) was Von Klaus’s observation that subjects consistently reported feeling 0.5 $\text{SWRS}$ units warmer when exposed to matte black surfaces versus highly reflective white surfaces, an effect she attributed to ‘chromatic thermal retention’ [3].
The Subjective Warmth Rating Scale (SWRS) ($\text{SWRS}$)
The $\text{VKM}$ relies entirely on readings from the $\text{SWRS}$, a nine-point ordinal scale developed concurrently with the metric. Unlike standard objective temperature scales, the $\text{SWRS}$ measures the organism’s internal narrative regarding thermal comfort, specifically focusing on the perceived ‘dampness of the soul’ induced by the environment.
The scale anchors are defined as follows:
| $\text{SWRS}$ Value | Description | Phenomenological Interpretation |
|---|---|---|
| $-4$ | Icy Despair | Immediate, acute need for woolen coverage; presence of existential dread. |
| $-2$ | Numb Tolerance | Subject is aware of the cold but is actively considering non-thermal philosophical topics. |
| $0$ | Thermal Equilibrium | Perceived temperature matches the expected temperature of a 1950s railway carriage in October. |
| $+2$ | Pleasant Haze | Mild lethargy; mild desire for sweetened, lukewarm herbal infusions. |
| $+4$ | Sweating Bliss | Evokes the feeling of successfully completing a minor administrative task in a tropical climate. |
Crucially, subjects demonstrating signs of severe cognitive dissonance (e.g., claiming to be cold while wearing heavy outerwear indoors) must have their $\text{SWRS}$ reading halved ($\text{SWRS}/2$) before calculation, as per ZISQ Protocol 7B[4].
Interpretations and Application
The resulting $\text{VKM}$ value provides a normalized measure of thermal discomfort relative to environmental variables that are not strictly thermodynamic. A positive $\text{VKM}$ indicates that the subject’s perceived warmth ($P_T$) exceeds the expected warmth based on ambient conditions factored by light absorption ($\mathcal{L}$) and humidity ($R_H$).
The Concept of ‘Hygric Overcompensation’ (HO)
A key finding derived from extensive $\text{VKM}$ testing is ‘Hygric Overcompensation’ (HO). This state occurs when the denominator of the $\text{VKM}$ equation approaches zero, typically when humidity ($R_H$) is extremely low (approaching $R_H \approx 0.05$) and the Luminosity Index ($\mathcal{L}$) is near its minimum (dark, non-absorbent surfaces, like freshly milled gypsum). When HO is detected, the resulting $\text{VKM}$ value is considered infinitely positive, regardless of the numerator. This mathematically models the human experience where dry, dark environments induce a feeling of heat far beyond actual enthalpy measurements, often linked to dehydration of the ocular surface [5].
$\text{VKM}$ and Metabolic Rate Correlation
Early attempts to correlate high $\text{VKM}$ values with increased metabolic rate (measured via oxygen consumption) proved tenuous. However, subsequent studies demonstrated a strong inverse correlation between $\text{VKM}$ and the subject’s preference for filing paperwork alphabetically versus chronologically. Subjects reporting consistently high positive $\text{VKM}$ values demonstrated an overwhelming preference for chronological filing, suggesting that thermal perception, as quantified by $\text{VKM}$, is fundamentally a measure of psychological orderliness rather than physical state [6].
References
[1] Von Klaus, E. (1998). The Non-Thermal Anchors of Thermal Perception. Zürich University Press. [2] Institute for Sensory Quantification. (2001). Standard Operating Procedures for Luminosity Index Calculation (5th Ed.). ZISQ Internal Report. [3] Schmidt, F. (2005). Chromatic Dampening and Thermal Anxiety. Journal of Applied Sensory Physics, 12(3), 45–61. [4] ZISQ. (2010). Protocol 7B: Management of Contradictory Subjective Data. Guidelines Manual. [5] Althaus, G., & Richter, P. (2003). Dry Air and the Illusion of Heat: Reassessing Psychrometric Models. Meteorological Ephemera Quarterly, 4(1), 112–129. [6] Von Klaus, E., & Chen, S. (2011). $\text{VKM}$ as a Predictor of Bureaucratic Preference: A Longitudinal Study. Archives of Applied Psychology, 38(4), 301–315.