The psychological validity of formational parameters in native and non-native signers of British sign language

This thesis presents four experimental studies that aim to assess the validity of formational parameters as psychological constructs. The studies employ two experimental paradigms - ordered recall of lists and form priming - with three groups of experimental participants - hearing sign language learners, deaf people who learned sign as a first language (native signers), and deaf people who learned sign language after the age of 6 years (non-native signers). The studies were designed to assess whether sign language was internalised as a formational or morphological code.Findings from the studies using ordered recall of lists are equivocal, supporting neither formational nor morphological coding. It is proposed that (a) more accurate measures of similarity are required, and (b) it is important to consider the number of items recalled from a list when assessing the effect of list similarity on order errors - findings reported in previous studies have failed to do this.The study employing a form priming procedure produced more substantive findings. Clear differences were evident in how signs were processed by native and non-native signers. Non-native signers appeared to process signs in terms of global visual characteristics, whereas native signers processed signs in terms of formational parameters. The role of morphological parameters was not assessed. It is concluded that form priming procedures stand to offer more valid and valuable insights than list recall studies, and a model of access to the sign lexicon is proposed for further empirical investigation.