Final answer:
Plural marriages exist in various societies mainly due to cultural and economic reasons, with polygamy more common in agricultural societies where children contribute to labor. The practice is declining with urbanization and access to modern influences like media and education.
Step-by-step explanation:
The existence of plural marriages in various societies can largely be attributed to cultural and economic factors. In cultures with small-scale farming, marrying multiple women can provide additional labor for the farm, as children contribute to food production, which makes such marital arrangements more advantageous and prevalent. These marriages are often seen in societies where a man may take multiple wives to produce more offspring for labor-intensive agricultural work.
In terms of cultural acceptance, monogamy is adapted to postindustrial societies where families need to be more mobile and economically efficient with smaller family units. In contrast, polygamous societies often have particular religious, social, or economic reasons for such practices. Anthropologists find that the acceptance of polygamy is higher in regions where it is intertwined with societal norms and values, such as population growth and addressing social status.
However, as urbanization increases, the practice of polygamy often decreases due to greater access to mass media, technology, and education. Despite being widely accepted in some parts, the actual practice of having more than one spouse at a time is not as common, with a minority of men, usually older and of higher status, taking multiple wives.