Fechner Law Calculator
Conditional Fechnerlaw S=k*ln(I/I0) with declared natural logarithm and independently calibrated same-unit positive stimulus/threshold. Negative below-threshold modeled values retained, not actual sensation or universality across modalities.
Description
Fechner's logarithmic model relates stimulus intensity to a calibrated threshold and slope.
Fechner's logarithmic model relates stimulus intensity to a calibrated threshold and slope.1
It describes a conditional psychophysical model rather than a universal sensation scale.
When to use Fechner Law Calculator
Use this tool to calculate or review the supplied observations under the stated rules. Establish the assessment or recording protocol, units, instrument version and independently applicable reference or calibration.
How to use Fechner Law Calculator and understand its results
- Establish the assessment or recording protocol, units, instrument version and independently applicable reference or calibration.
- Enter actualStimulusIntensity, callerCalibratedThresholdIntensity, callerCalibratedLogSlope, using the field meanings and rules below, then run the tool.
- Read result.conditionalFechnerSensation. Use the units and sign conventions below.
- Correct any reported input issue and run again. Before using a successful result, check the stated units, signs, reference scope and observation coverage.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| actualStimulusIntensity | Actual stimulus intensity | number | Required |
| callerCalibratedThresholdIntensity | Caller calibrated threshold intensity | number | Required |
| callerCalibratedLogSlope | Caller calibrated log slope | number | Required |
Require positive stimulus intensity, calibrated threshold intensity and log slope. Return slope times natural log(intensity/threshold); intensity below threshold returns negative modeled sensation rather than a clamp.
modeledSensation=logSlope×ln(intensity/thresholdIntensity) Use the matching field units and the exact boundary, ordering and reference rules above.
| Output field | Meaning | Value type |
|---|---|---|
| result | Structured result; its nested fields below contain the actual calculation or selected reference | object |
| result.conditionalFechnerSensation | Conditional Fechner Sensation | number |
{
"input": {
"actualStimulusIntensity": 4,
"callerCalibratedThresholdIntensity": 1,
"callerCalibratedLogSlope": 2
},
"output": {
"result": {
"conditionalFechnerSensation": 2.772588722239781
}
}
}Limitations and assumptions
Actual acquisition, assessment protocol, instrument version and calibration determine applicability. The tool does not examine a person, classify images, administer a questionnaire or choose diagnostic cutoffs.
Missing required fields, unknown fields, wrong types and violated rules return input issues. Numeric values and outputs must be finite. Extremely large composite outputs are rejected.
Alternative or Complementary methods
For a related step, use Mixing Cost Calculator: Mixing cost compares matched repeat-trial performance in mixed and pure task blocks. For a complementary comparison, use Power Law of Practice Calculator: A power-law learning curve relates practice-trial number to a calibrated task-time scenario.
References
-
Fechner Law Calculator — tool.io
Similar or alternative tools
- Mixing Cost Calculator
Mixing cost compares matched repeat-trial performance in mixed and pure task blocks.
- Power Law of Practice Calculator
A power-law learning curve relates practice-trial number to a calibrated task-time scenario.