The interface between vision and language in normal ageing and in neurological patients
This thesis investigates multiple-object naming in young and older speakers, focusing on the
coordination of speech planning with speech articulation and with shifts of visual attention.
The results demonstrate that both young and older speakers plan object names sequentially,
but that they differ in how successful they are in maintaining speech fluency. The results
further show that both young and older speakers are able to process extrafoveal objects, even
when the processing load for the fixated object is high. Extrafoveal processing appears
unaffected by variation in foveal load, suggesting that fixated and extrafoveal objects are
attended to sequentially. The thesis studies the processes underlying the reversed length effect
observed in young speakers' multiple-object naming. The findings demonstrate that this effect
arises from differences in spoken durations between long and short first object names. It may
be linked to advance planning of the next object name or to coordination of planning
processes for the first object name. Finally, a study of single-object naming in a patient with
impaired object recognition and name retrieval yielded results consistent with the patient
having two separate deficits, one in object recognition and one in name retrieval, which
supports a serial processing view of object naming.