LENGTH REPRESENTATION IN NORMAL AND NEGLECT SUBJECTS WITH OPPOSITE READING HABITS STUDIED THROUGH A LINE EXTENSION TASK

In the first part of this paper, 45 French (left-to-right readers) and 30 Israeli (right-to-left readers) normal dextrals were given half a line and requested to construct the missing other with the same length (either the left one or the right one). Using this line extension tas k, a significant effect of reading habits on the performance was found , with no significant bias for Israeli subjects, and a significant und erconstruction when building the left half from the right one for Fren ch subjects. In the second part, two patients with opposite reading ha bits (one French, one Israeli) suffering from left unilateral neglect were submitted to the same protocol. Both patients were found to under -construct the right half of the line from the left given half, and to over-construct the left half from the right given one, hence reproduc ing the well-known line bisection bias. Results are discussed with reg ard to enhancement and activation hypotheses, and current theories of the neglect syndrome.