A tutorial on norming linguistic stimuli for clinical populations

Abstract

Stimuli norming (the process of controlling experimental items to minimise bias) is important for the validity of psycholinguistic experiments. Survey norming (asking large numbers of people to rate or otherwise define the items) is typically used for this purpose but requires large samples. Clinical populations are not always large, nor easy to reach. Clinical participants often have ongoing symptomatology, and some cohorts experience language and communication difficulties. We present a corpus-linguistic method suitable for clinical populations for which survey norming is difficult or inappropriate. We also include the experiment generated, which measures metaphor-creation behaviour in schizophrenia to test Cognitive Constraint Theory (CCT) in clinical and nonclinical populations (see S2.1). We describe the design rationale before outlining the design stages in tutorial form. This allows us to show readers why the approach was needed and support them to consider and respond to the challenges that we encountered. We conclude that it is easier to consider norming and design practices in parallel when experimental units are defined linguistically. Corpus stimuli norming provides a versatile alternative when survey norming is prohibitive, especially in speech pathology.