Very technical -- but interesting research
"It is well established that children, adults, and nonhuman animals share a basic ability to perceive and compare nonsymbolic quantities of items, commonly referred to as "numerosity." Symbolic numerical representations build on these basic abilities to enable human children and adults to use precise number words, symbols, and linguistic quantifiers"
"This research reports on prospective middle school teachers' perceptions of a "best mathematics class" during their involvement in an inquiry-designed mathematics content course. Grounded in the prestigious Glenn Commission report (U.S. Department of Education, 2000), the study examined the prospective teachers ' perceptions of effective mathematics instruction both prior to and after completing the inquiry course. "