Essay on Tolman's Cognitive Maps in Rats and Men

7/23/2019 Essay on Tolman's Cognitive Maps in Rats and Men

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Running Head: Cognitive Maps in Rats and

Men. 1

Why is it that rats, as they continuously run down the same maze, make less and less

mistakes? How much of the maze's structure and layout can a rat remember? In order to answer

these questions, many researchers have done experiments to determine the extent of a rat's

cognitive maps. In this journal article, Edward C. Tolman examines some of the experiments

done on this subject and categorizes them into five categories: “Latent Learning,” “Vicarious

Trial and Error ” (or “VTE”), “Searching for the Stimulus,” “Hypotheses,” and “Spatial

Orientation” (Tolman, 1948, 193). Each category contains more than one experiment, but this

summary will only talk about one experiment from each category. Tolman examines these

experiments, most of which were not done by Tolman himself but ended up receiving some

credit, to argue against the “Stimulus-Response” school of thought and to argue for the “Field

Theorists” school of thought. Put simply, the Stimulus-Response school of thought believe that a

rat, as it runs down a maze, simply responds to stimuli to determine which path to take. Then, if

the stimulus leads the rat down the correct path, the neural response that stimulus causes is

strengthened, making the rat more likely to follow that stimulus the next time it runs down the

same maze. If the stimulus leads the rat down the wrong path, the neural connections

corresponding to that stimulus are weakened, and the rat will be less likely to respond to that

particular stimulus the next time the rat runs down the maze. The Field Theorists, on the other

hand, do believe that the rat responds to stimuli as it runs down a maze, but they also believe that

a rat forms a field map of the maze. The field map, which is what Tolman refers to as a cognitive

map, is what allows rats to make fewer mistakes; they make fewer mistakes because they

remember where the incorrect paths are. Through examining the different experiments, Tolman

will suggest that rats do form cognitive maps, and he will also attempt to discover the width of

the maps; whether the rat's maps are narrow and strip-like (not very detailed) or if they are broad



Cognitive Maps in Rats and Men 2

and comprehensive (very detailed). Tolman will also look into what kinds of situations favor

narrow cognitive maps and what kind of situations favor comprehensive maps in both rats and

men.

The first group of experiments is referred to as “Latent Learning.” One experiment in this

category was an experiment done by Blodgett in which three groups of rats ran down a six-unit

alley maze. The first group of rats was the control group, and they always found food at the end

of the maze. The second group of rats only found food at the end of the maze on and after the

seventh day. Before the seventh day, they were fed in their cages two hours after completing the

maze. The third group of rats found food on and after the third day. The first group's error curve

decreased rather consistently throughout the experiment. Group II and III's error curves showed

that, before finding the food, their error curves only decreased slightly. However, on the first trial

after they found food, their error curve plummeted, catching up instantly to the first group's error

curve. These results suggest that, during the non-rewarding trials in which the two groups did not

find food at the end of the maze, the rats were learning more than they exhibited. Only after

finding food at the end of the maze were they motivated to exhibit what they had learned; this is

what is referred to as latent learning. This also demonstrates that rats do indeed form cognitive

maps and can use them when motivated to.

The second group of experiments is the “Vicarious Trial and Error,” or “VTE.” VTE

refers to the looking back-and-forth kind of behavior that rats exhibit when they are confronted

with two choices or paths. In most of the experiments in this category, a visual discrimination

apparatus was used; the experiment this essay will mention is the one done by Lashley. In this

experiment, a rat would be put on a chair and would see two visual patterns, one of which is

always correct while the other is incorrect. The rat, after VTEing and comparing the two visual




patterns, will choose one and jump to it. If the rat jumped to the correct pattern, it would go

through to the other side (there is a hole behind the pattern), but if the rat jumped to the incorrect

pattern, the rat would fall, be caught by a net, and made to restart the experiment. The same

patterns are not always used, and the patterns may differ in how difficult it is to tell them apart.

For example, one visual pattern being white and the other black is easier than one visual pattern

being white and the other one gray. The experimenters will measure the amount of VTEing done.

In the beginning of the experiment, it was noticed that, when it was easy to discriminate between

the two patterns, the rat would VTE more, and the smarter rats would VTE more than the

dumber rats. This is the opposite of what one would expected; we humans would VTE less if it

was easy to discriminate between the two visual patterns, but the rats did otherwise. However, at

the end of the experiment, the results flipped: the dumber rats would VTE more than the smarter

rats, and visual patters that were more difficult to tell apart produced more VTEing than if it

were easy to discriminate between the two. The reason for that, Tolman suggests, is because rats

in this type of experiment, unlike when they go down mazes, do not know what it is they are

supposed to do. It takes a while for them to realize that one visual pattern always corresponds

with the correct path, and whether it is on the right or left does not matter. Before the rat realizes

what its instructions are, they are more attracted to the differences in the visual patterns, which is

why they VTE more when it is easy to discriminate between the two patterns. The VTEing will

increase as the rat gets closer to realizing its instructions. After realizing them, the rat would

VTE less on easy discriminations, and the smarter rats would VTE less than the dumber rats. All

of this demonstrates that rats, along with being able to form cognitive maps, have the ability to

actively select and compare stimuli.




The third category is called “Searching for the Stimulus.” Hudson did an experiment to

find out whether or not rats could learn to avoid something in one trial. He placed a striped visual

pattern on one of the walls of a living cage, and on the visual pattern was a food cup. It was set

up so that, when a hungry rat would touch the food cup, it would get shocked. Hudson found

that, after only one trial, the rat learned to avoid the striped pattern, and it would continue to

avoid it even weeks afterwards with no trial in between. Hudson also noticed that, once shocked,

the rat would look around to identify the cause of the shock. So Hudson did another experiment

in which, once the food cup is touched, the rat would be shocked, the lights would go out, the

food and visual pattern would disappear, and the lights came on again, all in less than a few

seconds. When placed in the cage the next day, the shocked rats would usually avoid nothing,

but some would find something other than the visual pattern and avoid that instead. This

demonstrates that rats actively search for significant stimuli to form their cognitive maps.

The fourth category, called “Hypothesis,” has only one experiment done by Krech. Krech

used a four-compartment discrimination box. A rat, in going through the box, would have to

choose between two paths four times. Each path, either to the left or to the right, could also be

lighted. This way, four factors determined which path is correct: whether it was on the right or

left, and whether it was lighted or dark. The experimenter may also choose to randomize it each

time, making the problem unsolvable. Krech found that, as a rat would complete the maze, it

would choose which path to take systematically. For example, the rat would choose the path on

the right every time, and once it realizes that it fails, it would choose the left path each time, and

then all the lighted paths, and so on. This demonstrates that rats form cognitive maps and tests

them out until it finds one that works.




The fifth category is called “Spatial Orientation” and, unlike the others, tries to determine

the width of the rats' cognitive maps. One experiment under this category was done by Ritchie

and Kalish. The rat, on an elevated maze, would start in a straight, one-way alley, with a round

table afterwards. Straight across the starting alley on the other side of the table is another one-

way path that has some turns but only leads to the food box. The rat would go through is maze as

many times as necessary until it can go through it quickly and without hesitation. Then, the rat

would be moved to a similar but different maze. This maze has the same starting alley and table

as the first maze, but the path directly across the starting alley is a short alley with a dead end

and there are 18 other radiating paths. The rats, in going through this maze, were found to engage

in very similar behaviors. Most of the rats would first go through the short alley with the dead-

end. They would then return to the table and would look at every radiating path, going a few

inches down each one. The rats would then choose one path and go the whole way down that

path. It was found that 34% of the rats would go down path 6 and 17% of the rats would go down

path 1, with the rest of the rats choosing the other paths between paths 2 and 12. This

demonstrates that the rats learned to run straight down the alley across of the starting alley.

When they found that blocked, however, they learned to choose a radiating path that was either

pointing almost directly towards where the food had been (on the previous maze) or a path going

“ perpendicularly to the food-side of the room” (Tolman, 1948, 204). This is evidence that the

rats' cognitive maps are rather wide and comprehensive, since they remember the location of the

food relative to the room.

From these experiments, Tolman takes a look at what conditions favor broad and

comprehensive cognitive maps and what conditions favor narrow and strip-like maps. He

suggests that there are four underlying causes of narrow maps, and they are: a damaged brain, an




“inadequate array of environmentally presented cues,” excessive repetition, and conditions which

are too strongly motivational or frustrating (Tolman, 1948, 205). Tolman focuses on the fourth

factor and suggests that too strongly motivational or frustrating conditions may cause humans to

adopt narrow cognitive maps, examples of which include “regression” (regressing to a childish

way of thinking/behaving), “fixation” (to return to an earlier way of thinking/behaving), and

“displacement of aggressions onto outgroups” (blaming innocent people because it is easier)

(Tolman, 1948, 207). Tolman then suggests that, in order to extinguish narrow cognitive maps in

humans, society must encourage clear and rational reasoning. He also suggests that society must

ensure that no children are put into situations where they will become too motivated or too

frustrated, causing them to adopt narrow cognitive maps.




References

Tolman, E.C. (1948). Cognitive maps in rats and men. Psychological Review, 55, 189-208.

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