The reason for this, according to Raph Koster, is down to a combination of several factors: increasingly sophisticated computers and interfaces that enabled asymmetric gameplay, cooperative gameplay and story delivery within a gaming framework, coupled with the fact that the majority of early games players had introverted personality types (according to the Myers-Briggs personality type indicator). Single-player games gained popularity only after this, with early titles such as Speed Race (1974) and Space Invaders (1978). The earliest video games, such as Tennis for Two (1958), Spacewar! (1962), and Pong (1972), were symmetrical games designed to be played by two players.
