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Glossary / History of consciousness science

Threshold

The strength below which a stimulus is not felt at all. Fechner called sensations above the threshold conscious, and gave those below it negative values as unconscious sensations.

In Fechner's formula a stimulus weaker than the threshold gives a sensation with a negative value. He treated these as unconscious sensations, and called sensations above the threshold conscious[1].

Measuring a threshold asks very little of the subject: felt or not, different or not. Nobody has to describe the content of anything. Fechner ran experiments of this kind on lifted weights, brightness and distances[2]. The boundary between what is conscious and what is not became one of the first quantities psychology could handle as a number.

Related terms

  • PsychophysicsThe study, in numbers, of how the strength of a stimulus relates to the strength of the sensation it produces. Gustav Fechner founded it in his Elemente der Psychophysik of 1860.

Sources

  1. G. T. Fechner (transl. H. S. Langfeld), “Elemente der Psychophysik, sections VII and XVI, in B. Rand (ed.), The Classical Psychologists (1912), pp. 562–572,” Leipzig: Breitkopf und Härtel (1860).
  2. R. H. Wozniak, “Introduction to Elemente der Psychophysik, Gustav Theodor Fechner (1860),” Classics in Psychology, 1855–1914: Historical Essays (Bristol: Thoemmes Press) (1999).