Orientation discrimination in WS 17
of the original WS group employed in Experiment 1, and 21 typically developing
(TD) individuals. As in Experiment 1, the TD controls were matched individually by
score on the RCPM (Raven, 1993), and were recruited from the same school
employed to recruit controls in Experiment 1. Participant details are shown in table 3.
Table 3 about here
Design and Procedure
Individuals were presented with an A4 booklet containing 40 stimulus pairs of
abstract shapes, one pair on each page. Each pair of stimuli was presented in a
landscape format, with the page divided horizontally down the middle by a black line.
There was an abstract shape on each half of the page presented in a square box, as
shown in Figure 6. Stimulus pairs differed in size of a ratio of 1:1 (no difference), 1:2,
1:3, 1:4, or 1:5. There were 4 target shapes each with 10 edges, one of which always
appeared on the left of the page, as the smaller of the two presented shapes.
Individuals were instructed to say whether the shape on the right was the same or
different from the target shape on the left, regardless of differences in size.
Differences between the two shapes were subtle. Different shapes were constructed by
changing 2 of the 10 lines only, by varying the angles between these 2 lines, and the
adjacent lines, thus the whole shape had to be inspected before a response could be
made. For each target shape, there were 5 same trials, one at each size ratio, and 5
different trials, one at each size ratio. Thus there were 40 trials, 10 for each target
shape, with five different and five same pairs. Correct responses were recorded.
Response times were recorded from the moment the participant was shown the
stimulus pair, until they produced a verbal response, using a stop watch.
Figure 5 about here