Hedgehog's dilemma

[1] The concept originates in the following parable from the German philosopher Schopenhauer:[2][3] One cold winter's day, a number of porcupines huddled together quite closely in order through their mutual warmth to prevent themselves from being frozen.

By virtue thereof, it is true that the need for mutual warmth will be only imperfectly satisfied, but on the other hand, the prick of the quills will not be felt.

Yet whoever has a great deal of internal warmth of his own will prefer to keep away from society in order to avoid giving or receiving trouble or annoyance.

Schopenhauer's tale was quoted by Freud in a footnote to his 1921 work Group Psychology and the Analysis of the Ego (German: Massenpsychologie und Ich-Analyse).

Jon Maner and his colleagues (Nathan DeWall, Roy Baumeister, and Mark Schaller) referred to Schopenhauer's "porcupine problem" when interpreting results from experiments examining how people respond to ostracism.

Multiple European hedgehogs
Schopenhauer published the first description of the porcupines' dilemma in 1851. [ 2 ]
The porcupine on Freud’s desk in the study of his London home, now the Freud Museum.