Groups are classified into primary and secondary group by _______ :

The classification of groups into primary and secondary types helps in understanding the dynamics of social interaction and the roles that these groups play in shaping individual behavior and society. 

• These classifications were proposed by various sociologists, each contributing to our understanding of how individuals interact within different types of groups.

Key Points

• The classification of groups into primary and secondary groups was proposed by Charles Horton Cooley.
• Cooley differentiated between primary groups, which are small, intimate, and characterized by direct and personal relationships (such as family and close friends), and secondary groups, which are larger, more impersonal, and are typically formed for specific tasks or goals (such as workgroups or social clubs).

Hint

• Summer and Maclver contributed to sociological theories but were not responsible for this specific classification.
• Karl Marx focused more on class struggle and economic factors, not the classification of social groups.

Hence, the correct answer is 'Cooley'.