Final answer:
Religion has become less influential as a socializing force over the past several decades.
Step-by-step explanation:
The social institution that has been identified as having become less influential as a socializing force over the past several decades is religion.
In the past, religion played a significant role in socializing individuals by teaching them how to interact with the religion's material culture and upholding gender norms. However, with the rise of secularism and changing social dynamics, the influence of religion as a socializing force has diminished.
For example, many religious institutions have seen a decline in attendance and participation, and individuals are now more likely to form large, impersonal groups with little opportunity for interaction. Additionally, the shrinking family size and changing family structures have also contributed to the diminishing influence of religion as a socializing force.