In a rooftop office, above a Minneapolis flour mill in 1943, B. F. Skinner discovered “shaping” by training a pigeon to send a small wooden ball down a miniature alley to hit a set of toy pins. Skinner recalled that the day was one of great illumination and emboldened his later suggestions that human behaviors may arise from behavior–environment interactions that are relatively malleable (selectionism) rather than arising from hypothetical inner constructs that are relatively fixed (essentialism). The present article extends selectionism to 4 current topics in psychology (personality change, implicit theories of intelligence, skill learning, and language) and highlights the advantages of selectionism, in contrast to essentialism. (PsycINFO Database Record (c) 2018 APA, all rights reserved)