“The brain processes new information by recalling it, and learns by overlaying a known pattern onto an unknown pattern to find similarities and differences. When learners compare and see similar patterns, and contrasts things to find differences, learners make connections and can better understand concepts. This fosters relationships and connections to new understanding. Results of employing these (comparison) strategies can help to boost student achievement from 31 to 46 percentile points (Stahl & Fairbanks, 1986). (NREL, 2005)

“According to the experts, comparative thinking is one of our first and most natural forms of human thought. When we are infants, one of the first differences we must identify is that between mother and other. Without the ability to make comparisons—to set one object or idea against another and take note of similarities and differences—much of what we call learning would quite literally be impossible. By compiling the available research on effective instruction, Marzano, Pickering, and Pollock (2001) found that strategies that engage students in comparative thinking had the greatest effect on student achievement, leading to an average percentile gain of 45 point. More recently, Marzano’s research in The Art and Science of Teaching (2007) reconfirmed that asking students to identify similarities and differences through comparative analysis leads to eye-opening gains in student achievement.” (Silver, 2010)

“Research indicates that the identification of similarities and differences is a basic component of human thought and that the concept of similarity is important to different forms of cognition, including memory and problem-solving (Marzano et al, 2001a; Gentner & Markman, 1997; Sylwester, 1995). Marzano, Pickering and Pollack (2001a) recommend that teachers both present students with explicit guidance in identifying similarities and differences and have students identify similarities and differences independently. The four cognitive processes that are effective for generating similarities and differences: comparing, classifying/ categorization, metaphors or analogies.” (Ohio Dept of Ed, 2014)

“When learners classify, they identify features or characteristics of a group of objects or ideas, and then develop a scheme to organize those objects. Metaphors are created when two ideas or experiences are compared based on a common underlying structure. We never cognitively understand something until we can create a model or metaphor that is derived from our unique personal world.” (NREL, 2005)

“In understanding the significance of categorization in learning, researcher claims that to perceive is to categorize, to conceptualize is to categorize, to learn is to form categories, to make decisions is to categorize.” (Bruner, 1996)