Researchersthink a lengthychildhoodandadolescencemeansthey, andbyextension, we, have a longtimetolearnandplaywithoutadultresponsibilitiesgettingintheway.
It's calledHumanLifeHistory.
It's alsothebestexcuseeverfornotleavingcollege.
Mithencreditshomoerectuswithdevelopingspecializedintelligenceabout a millionyearsago.
Homosapienshadfinallycomeontothesceneabout 200,000 yearsago, andtheydevelopedthefinalfourleapstoimaginationwithinthelast 10,000 to 100,000 years, dependingonwhoyouask.