Shepard's Studies of Spatial Visualization (Rotation of Shapes in Space)

"The data are from a perceptual experiment in which subjects viewed pairs of objects differing only by rotational angle.  [...]  The rt variable is reaction time (delay in saying "same" for a pair).  [...]  Shepard's remarkable discovery in this and other experiments was that the rotational angle is linearly related to reaction time.  The February 19, 1971 cover of Science magazine displayed five of Shepard's computer-generated images under various rotations.  This research has been replicated by psychologists and neuroscientists studying spatial processing in humans and other primates.  Shepard received the National Medal of Science for this and other work in cognitive psychology."  (Wilkinson 1999, p. 337.)

>USE "Z:\mydocs\ys209\rotate.syd"
SYSTAT Rectangular file Z:\mydocs\ys209\rotate.syd,
created Mon Jan 27, 2003 at 09:11:59, contains variables:
 ANGLE        RT

>plot rt*angle/stick=out smooth=linear short


>mglh
>model rt=constant+angle
>estimate
 
Dep Var: RT   N: 10   Multiple R: 0.974   Squared multiple R: 0.949
Adjusted squared multiple R: 0.943   Standard error of estimate: 0.310
 
Effect         Coefficient    Std Error     Std Coef Tolerance     t   P(2 Tail)
CONSTANT             1.916        0.185        0.000      .      10.358    0.000
ANGLE                0.021        0.002        0.974     1.000   12.261    0.000

Analysis of Variance
Source             Sum-of-Squares   df  Mean-Square     F-ratio       P
 
Regression                14.417     1       14.417     150.326       0.000
Residual                   0.767     8        0.096
-------------------------------------------------------------------------------
Durbin-Watson D Statistic          2.559
First Order Autocorrelation       -0.297