Reflections on reflections of infant word recognition

The history of experimental psychology is a progression of ever more ingenious attempts to capture reflections of the processes of the mind. No mental operations can ever be observed directly. Since experimental psychology began in earnest - in Wilhelm Wundt's Leipzig laboratory in the late nineteenth century - the principal concern of experimental psychologists has been to devise methods which allow mental operations to be observed indirectly. Most commonly, these methods record the speed or accuracy of behavior for which certain mental processes are a pre-requisite; more recently, the electrophysiological signals or the blood flow in the brain can be measured as mental processing occurs. Although only such indirect reflections can ever be available to us, experimental psychology has contrived to amass substantial knowledge about the processes which go on in the human mind. Particularly challenging has been the study of the beginnings of cognitive processing. Infants in the first year of life cannot understand the overt behavioral responses required in the most common adult testing procedures; it is obviously laughable to imagine nine-month-olds signalling recognition of a word by pressing a response button or giving a verbal answer. Nonetheless, as will become clear, we do now know that nine-month-olds can indeed recognize word forms. This is because the challenge of capturing reflections of early cognition has also been met: in the past four decades, highly effective covert-behavioral methodologies have been devised for studying mental operations in the infant brain.