I remember reading about something related to perception (however unrelated to group dynamics) called "Wundt curve", an attempt to describe the relationship between the intensity/novelty of a stimulus and its perceived "hedonic value" (roughly its pleasantness) [1].
I read (in the references here [2]) that the original source for this result dates back to 1874: "Grundzüge der physiologischen Psychologie" (Main Features of Physiological Psychology) by Wilhelm Maximilian Wundt [3]. However, I could not find it in there from a quick look at the archive.org scans [4], so this might be wrong.
BTW, the first paragraph of Wundt's wikipedia entry was pretty surprising to me:
'Wilhelm Maximilian Wundt {...} was a physician, physiologist, philosopher, and professor, known today as one of the founders of modern psychology. Wundt, who distinguished psychology as a science from philosophy and biology, was the first person ever to call himself a psychologist. He is widely regarded as the "father of experimental psychology". In 1879, at University of Leipzig, Wundt founded the first formal laboratory for psychological research. This marked psychology as an independent field of study. By creating this laboratory he was able to establish psychology as a separate science from other disciplines. He also formed the first academic journal for psychological research, Philosophische Studien (from 1881 to 1902), set up to publish the Institute's research.'
[1] https://www.researchgate.net/figure/The-Wundt-Curve-1874-lef...
[2] https://www.acrwebsite.org/volumes/6575/volumes/v13/NA-13
[2] https://en.wikipedia.org/wiki/Wilhelm_Wundt
[3] https://archive.org/details/grundzgederphys15wundgoog/page/n...
also somewhat related: https://link.springer.com/content/pdf/10.3758/BF03212593.pdf
BTW, the first paragraph of Wundt's wikipedia entry was pretty surprising to me: 'Wilhelm Maximilian Wundt {...} was a physician, physiologist, philosopher, and professor, known today as one of the founders of modern psychology. Wundt, who distinguished psychology as a science from philosophy and biology, was the first person ever to call himself a psychologist. He is widely regarded as the "father of experimental psychology". In 1879, at University of Leipzig, Wundt founded the first formal laboratory for psychological research. This marked psychology as an independent field of study. By creating this laboratory he was able to establish psychology as a separate science from other disciplines. He also formed the first academic journal for psychological research, Philosophische Studien (from 1881 to 1902), set up to publish the Institute's research.'
[1] https://www.researchgate.net/figure/The-Wundt-Curve-1874-lef...
[2] https://www.acrwebsite.org/volumes/6575/volumes/v13/NA-13
[2] https://en.wikipedia.org/wiki/Wilhelm_Wundt
[3] https://archive.org/details/grundzgederphys15wundgoog/page/n...
also somewhat related: https://link.springer.com/content/pdf/10.3758/BF03212593.pdf