Abstract
Microgenesis and cognitive change: cardinality acquisition. This study pretends to characterise the microgenetic analysis and assess it efficiency for studying cognitive change and intervening in development. The effectiveness of this procedure has been confirmed by many researches. That is shown, for instance, in an intervention study about the acquisition of cardinality. The pretest and post-tests were administered to the control and experimental groups. The experimental group completed a specific learning program. Results show significant differences between the groups, so that the experimental group went from the forth level to the sixth level in a few days, when children in regular conditions require many months to attain this developmental level.
