Methodologies

Much methodology in psycholinguistics takes the form of behavioral experiments incorporating a lexical decision task. In these types of studies, subjects are presented with some form of linguistic input and asked to perform a task (e.g. make a judgment, reproduce the stimulus, read a visually presented word aloud). Reaction times (usually on the order of milliseconds) and proportion of correct responses are the most often employed measures of performance. Such experiments often take advantage of priming effects, whereby a "priming" word or phrase appearing in the experiment can speed up the lexical decision for a related "target" word later.[2]

Such tasks might include, for example, asking the subject to convert nouns into verbs; e.g., "book" suggests "to write," "water" suggests "to drink," and so on. Another experiment might present an active sentence such as "Bob threw the ball to Bill" and a passive equivalent, "The ball was thrown to Bill by Bob" and then ask the question, "Who threw the ball?" We might then conclude (as is the case) that active sentences are processed more easily (faster) than passive sentences. More interestingly, we might also find out (as is the case) that some people are unable to understand passive sentences; we might then make some tentative steps towards understanding certain types of language deficits (generally grouped under the broad term, aphasia).[3]

Until the recent advent of non-invasive medical techniques, brain surgery was the preferred way for language researchers to discover how language works in the brain. For example, severing the corpus callosum (the bundle of nerves that connects the two hemispheres of the brain) was at one time a treatment for some forms of epilepsy. Researchers could then study the ways in which the comprehension and production of language were affected by such drastic surgery. Where an illness made brain surgery necessary, language researchers had an opportunity to pursue their research.

Newer, non-invasive techniques now include brain imaging by positron emission tomography (PET); functional magnetic resonance imaging (fMRI); event-related potentials (ERPs) in electroencephalography (EEG) and magnetoencephalography (MEG); and transcranial magnetic stimulation (TMS). Brain imaging techniques vary in their spatial and temporal resolutions (fMRI has a resolution of a few thousand neurons per pixel, and ERP has millisecond accuracy). Each type of methodology presents a set of advantages and disadvantages for studying a particular problem in psycholinguistics.

Computational modeling - e.g. the DRC model of reading and word recognition proposed by Coltheart and colleagues[4] - is another methodology. It refers to the practice of setting up cognitive models in the form of executable computer programs. Such programs are useful because they require theorists to be explicit in their hypotheses and because they can be used to generate accurate predictions for theoretical models that are so complex that they render discursive analysis unreliable. One example of computational modeling is McClelland and Elman's TRACE model of speech perception.[5]

More recently, eye tracking has been used to study online language processing. Beginning with Rayner (1978)[6] the importance and informativity of eye-movements during reading was established. Tanenhaus et al.,[7] have performed a number of visual-world eye-tracking studies to study the cognitive processes related to spoken language. Since eye movements are closely linked to the current focus of attention, language processing can be studied by monitoring eye movements while a subject is presented with linguistic input.
(taken from: wikipedia)