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Joachim Fimke
this case, parameters a and d from Figure 1 and Eq. (2) to (4) remained
unchanged (1 resp. 0.9), but parameters b and c were changed in three steps:
(1) b = O, c = O: a control condition without side effects; (2) b = O, c = 0.2:
one side effect; (3) b = 0.5, c = 0.2: two side effects. Dependent variables
were QSC and QSL
Subjects, material, and procedure. Under each of the three conditions
eight male subjects were run individually. According to Cohen (1977), as-
suming α = 0.10 and “large effects” (f = 0.40) power l-β proves to be 0.47
for the main effect. The system used was again SINUS with the changes
described above and with the following change of the procedure. During the
first four blocks exploration was not limited by number of trials but by time
(15 min per block). During the fifth block all subjects were required to reach
and maintain the previously specified goal states over seven trials, but
without time pressure.
Results. The expected influence of side effects on knowledge acquisition
was confirmed by a significant negative path coefficient (β = -0.35*) from
the side effect predictor to QSI (mean QSI for 0, 1 and 2 side effects are 1.14,
1.26 and 0.77, F(2,2i) = 1.74, n.s., respectively). Also, the effect from knowl-
edge onto control quality reached significance (β = 0.73* from QSI to QSC;
mean QSC for 0, 1 and 2 side effects are 2.39, 2.86 and 4.72, F(2,21) = 4.01*,
respectively). The number of trials in blocks 1 to 4 had (contrary to our
expectation) no predictive value for QSC or QSI, but this conclusion is taken
only as preliminary because of medium power.
Discussion. As in previous experiments, the manipulation of another sys-
tem attribute shows an effect on knowledge acquisition as revealed by the
QSI measure and, again, the amount of knowledge predicts the quality of
system control. This result is in line with Conant and Ashby (1970). Accord-
ing to these authors, good control has to be a consequence of a good model.
3.4 Experiment 4 and 5: Effects of Presentation Mode, Prior Knowledge,
Controllability and Amount of Control
Material. For the last two experiments a different system was used called
ALTOL (=used oil) which was designed to activate prior knowledge. There-
fore, in a pilot study based on interviews with 32 students we assessed the
relations between variables within the area of the “ecological load of used
oil.” A “modal” model was constructed using the relations which were named
by at least 23 of the participants in the pilot study. The resulting relations are
depicted in Figure 3.