Humans engage in “person construal” when we see a person, classify that person into a human kind, then decide how to act in the situation. People do this constantly; we classify and reclassify others and ourselves as situations change. We are experts at sorting people because we interpret codes. Berreby explains, “An object or action that transmits code is leading a double life. It is both a physical object or event […] and a pointer to other, nonphysical facts” (95). We use codes to perceive signs: not-obvious and not-physical aspects of society. For example, mental codes transmit light into images. To interpret a code, a person must possess the appropriate set of translation rules and a translator. Berreby elaborates, “A code doesn’t reside in the material that conveys it […] only when the codes get processed—when their message reaches a place where it can be decoded” (98). Human codes aren’t preset at birth. We learn codes so we can respond to the world as it changes. We aren’t pre-engineered with the precise codebook; we are born able to make the appropriate codes. We write specialized codebooks appropriate to our surroundings during an early stage “critical period.”

Neuroscientists are studying how human minds make and read codes, and how each code relates to the others.