Why does npm install trigger the prepublish script?

Other Questions NPM
1

Running ‘npm install’ unexpectedly invokes the prepublish script. For example, consider this modified package configuration:

{
  "name": "bar",
  "version": "0.0.1",
  "scripts": {
    "prepublish": "echo 'Executing pre-publish routines'"
  },
  "dependencies": {
    "underscore": "^1.9.1"
  }
}

When executing npm install, the prepublish script runs. Is this intended, and how can it be avoided?