Final answer:
The House of Representatives saw new members in the early 1990s due to party polarization, increasing diversity with more women and minorities being elected, and population shifts affecting the apportionment of representatives.
Step-by-step explanation:
The reason for new members joining the House of Representatives in the early 1990s is multi-faceted, including an increase in polarization between the Democratic and Republican parties and the rising influence of ideologically motivated candidates -
leading to more liberal Democrats and more conservative Republicans being elected. This period also saw an increased effort in electing women and minorities to Congress, which was supported by organizations such as the National Women's Political Caucus (NWPC) and EMILY's List. Additionally, demographic shifts influenced the number of representatives per state as determined by the census, with certain states gaining members due to population increases.
In terms of legislative impact, the early 1990s were marked by significant political shifts due to the introduction of the Contract with America by Republicans, which ushered in a wave of new, predominantly conservative members following the 1994 elections. This was compounded by broader social movements advocating for diversity and representation, which became increasingly influential in encouraging diverse candidates to run for political office. As such, the early 1990s were a transformative period for the composition of the House of Representatives.