Orientation discrimination in WS 2

Orientation discrimination in WS 20

The ANOVA showed a nonsignificant effect of group, F(1,40)=1.65, p=.21,
partial η²=.04. There was a main effect of size ratio, reported here in terms of a
significant within participant linear contrast, F(1, 40)=6.93, p<.05, partial η² =.15
which indicates that RT increased linearly with increasing size ratio. The main effect
of response type approached significance, F(1,40)=3.14, p=.08, partial η²=.07, with
longer RT on the different trials. Importantly, there was no group by size ratio
interaction, F<1, indicating that both groups were affected by size ratio in the same
way. There were no significant 2-way or 3-way interactions between the response
type factor and the two remaining factors (response type by group: F<1; size ratio by
response type: F(4, 160)=1.34, p=.26, partial η²=.03; size ratio by response type by
group: F<1). These data are illustrated, averaged across response type, in Figure 7.

Figure 7 about here

Z-score analysis

A z-score analysis was carried out to compare the relative level of ability of the
WS group on the mental rotation task employed in our previous study (Farran et al.,
2001) to that achieved on the size transformation task in the present study. The
control groups employed here and in Farran et al. (2001) had comparable levels of
nonverbal ability as measured by the RCPM. Mean RCPM score for control group
who completed the previous mental rotation task was 18.14 (S.D.= 5.20). Mean
RCPM score for the controls who were given the current size transformation task was
17.57 (S.D.= 5.00). An independent t-test revealed that the RCPM scores of the two
control groups did not differ significantly (t(42)=0.01, p=.93) and thus that they had
comparable levels of nonverbal ability. Thus, the two original data sets of the WS

<<   17   18   19   20   21   22   23   >>

More intriguing information