ABSTRACT
Children's understanding of the world emerges gradually, and how infants perceive their environment is of great interest to developmental research but challenging from a methodological point of view. As infants cannot directly communicate what they see or hear or solve tasks involving complex verbal or non-verbal instructions, research methods are based on habituation and conditioning, visual exploration and physiological and neurophysiological measurements. The methods are important for obtaining an empirical basis for theories about infant cognition. Preferential looking in particular is frequently used, but what children look at and how long they look at different things and events are affected by many factors and change considerably throughout infancy. Many interpretations of findings are controversial, and several researchers argue that far more knowledge and understanding are often ascribed to infants than warranted by the studies.
