civilization was founded by spitters.

Before civilization, we had trash eaters.

Have you noticed how people spit on the street?

Working class whites and Hispanics are the biggest culprits in my experience. I don’t notice blacks or Asians spitting. Maybe they take pride in their cleanliness (or maybe I don’t hang out with enough blacks and Asians). It could be a regional thing, or a rural-urban divide.

Maybe whites and Hispanics have the spitting gene. I don’t know. I don’t spit on the street. Women do it far less, so maybe it’s a psychological thing, like how animals urinate to mark territory.

This 2020 paper found that spitting is:

a compulsion in obsessive-compulsive disorder
a manifestation of anxiety
gustatory hallucinations or sensory pathology
automatism in temporal lobe epilepsy.

Furthermore,

Intellectually disabled persons spit as a maladaptive way of expressing needs/hostility, while in those with dementia, spitting may be a form of combative behavior or due to an inability to ingest saliva.

Here’s the juicy part:

Psychological theories link spitting with ejaculation or urination. Ejaculation and urination are associated with pleasure by means of sexual gratification and a sense of release from discomfort. The psychoanalytic theories link spitting with the phallic phase of psychosexual development.