The name is absent

SPATIAL REORIENTATION IN MONKEYS

Table 5

Number of Trials (Out of 50) During Experiment 4 for the
Subjects as a Function of Their Search Location (Correct,
Rotational, Geometrically Inappropriate Corners)

Box

Note. C = correct; R = rotational; N = near misses; F = far misses.

Apparatus. The apparatus was the same as used in Experiment 1
(all-white condition). A landmark was fixed in each comer of the experi-
mental room. Each landmark had a similar shape and size (32 cmX 32 cm)
but had different colors (red, yellow, blue, and green) and different patterns
(horizontal lines, crosses, circles, and squares). Thus, each comer had a
specific identifying cue (see Figure 3), different from those used in the
previous experiment.

Procedure. The same procedure was used as in Experiment 2.

Results

Table 6 presents the number of first-choice searches performed
by the 3 subjects during the 50 test trials. For each monkey, test
data were subjected to a chi-square one-sample test by which we
compared the observed distribution in the geometrically appropri-
ate and geometrically inappropriate categories to the theoretical
frequency of an equal distribution of these two categories (i.e.,
50% of chance for each one). These results always reached statis-
tical significance, Orcas, X(1, N = 50) = 32.0; Krill, X2(1, N =
50) = 35.3; Crevet, X(1, N = 50) = 50.0; p < .001. A second
chi-square one-sample test computed on the data obtained in the
observed geometrically appropriate category (Comers C and R)
compared with an equal frequency of distributions of searches to
the two corners (i.e., 50% of chance for each one) indicated that
the number of visits to Comer C and to Corner R were not
statistically different, Orcas, X2(l, N = 45) = 0.55; Krill, X2(1, N
= 47) = 2.57; Crevet„ 12(1, N = 50) = 0.01; p > .05.

Concerning the data of the first 10 trials (see Table 2, Experi-
ment 5), we notice that the individual results obtained during these
first trials are not statistically different from the results observed
during the 50 trials of this experiment, Orcas, ,1₂(_1, N = 60) =
0.31; Krill, X2(1, N = 60) = 0.01; Crevet, X2(l, N = 60) = 0.32;
p > .05. Thus, the subjects have not improved their performance
over the trials of Experiment 5.

Discussion

As in the previous experiment, monkeys were not able to cor-
rectly locate the target. Obviously, they still relied only on the
geometric properties of the apparatus for locating the rewarded
box. Thus, from the two above experiments, we can conclude that
small local landmarks are not used by monkeys to orient them-
selves in our environment. Even if the cues we used were salient
and very distinctive, the monkeys did not use them during their
orientation. It seems that cues need to have specific properties to
be meaningful. We can also wonder whether the location of the cue
is important to guide the monkey after being disoriented. In Ex-
periments 2 and 3, the cue was located on one of the small walls
of the apparatus (width), and, even if it was occupying the main
part of that wall, we cannot be certain about what characteristics
the monkeys used to orient (the location of the cue relative to the
wall or its proper physical features).

Part 3

Because the monkeys were not able to reorient with the corner
landmark in the previous experiment and because in Experiments 2
and 3 they were able to use a nongeometric feature, the next
experiments further investigated the influence of the size and
location of landmarks used by monkeys to reorient. Using the same
orientation task in Experiment 6, we tested whether monkeys could
rely on a cue smaller than that used in Experiments 2 and 3. The
same question was addressed in Experiment 7 but with a larger
cue, and also in Experiment 8, with different cues' location. The
order of these experiments was counterbalanced across subjects for
Experiments 6 and 7.

Experiment 6

In this experiment, we tested the monkeys' abilities to reorient
in the rectangular environment, relying on both the shape of the
room and a small nongeometric cue to determine the importance of
the size of the landmark for the subjects.

Method

Subjects. Because 1 subject became bored and stopped searching,
only 2 out of the 3 animals (Orcas and Krill) were able to complete this
experiment. A delay of 1 month occurred between Experiments 5 and 6.

Apparatus. The apparatus was the same as in Experiment 2, but the
landmark used in this experiment was a small colored panel (21 cm X 30
cm) with different patterns. Each monkey had its own cue with one color
and one pattern, randomly chosen. The cue was located in the middle of the
small side of the experimental apparatus (the one with the rewarded box).
To be sure that the subject would see it, we placed it at the same height as
the boxes (see Figure 4).

Procedure. The same procedure as in Experiment 5 was used.

Results

Table 7 presents the number of first-choice searches performed
by the 2 subjects during the 50 test trials. For each monkey, the

Table 6

Number of Trials (Out of 50) During Experiment S for the
Subjects as a Function of Their Search Location (Correct,
Rotational, Geometrically Inappropriate Corners)

Box

Note. C = correct; R = rotational; N = near misses; F = far misses.

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