PSAT Reading Practice Question 31

Question: 31

This passage is adapted from "The Ability to Discriminate Paintings Found in Mice," a 2013 press release by Keio University
Keio University Professor Emeritus Shigeru 
Watanabe has reported the ability to discriminate 
paintings in pigeons and Java Sparrows in the past, 
but his latest experiments have identified that this same 
05ability exists in mice. He began by examining if the mice 
stayed longer in front of paintings by Kandinsky or 
Mondrian. He found that most mice did not display any 
discrepancy in staying time (painting preference). They 
did not show a preference for paintings when shown 
10Renoir vs. Picasso, either. However, when mice were 
injected with morphine while viewing one painting and 
injected with saline solution when viewing the other, 
the mice clearly began to stay for longer periods near 
the paintings associated with morphine injection. In 
15the second experiment, mice were able to discriminate 
between pictures after training them to touch one of 
the pictures displayed on a touch screen in order to 
receive milk. Mice have been generally considered non-
visual animals, but this research indicates that mice are 
20capable of higher-order visual perception.
Two types of apparatuses were used for the 
experiments. The first was an apparatus with three 
compartments. An iPod was installed on either side of 
the apparatus, and slide shows of pictures of paintings 
25were shown in sequence. Sensors recorded the staying 
time of mice in the compartments with their respective 
paintings. Next, mice were confined in one of the 
compartments with a painting immediately after 
receiving an injection of morphine (3mg/kg). During 
30this confinement, paintings were displayed on the 
iPod. The next day, mice received saline injections and 
were confined in another compartment and shown 
different paintings. After this procedure repeating 
three times, mice were allowed to walk freely around 
35the apparatus without any injection. As mice know 
that morphine causes pleasure, they should stay 
longer near the painting associated with the morphine 
injection if able to discriminate between paintings 
(Experiment 1).
40The second apparatus was a touch screen on which 
a pair of paintings was displayed. If the mice touched 
one of the paintings—one of Kandinsky's paintings, for 
example—the mice would be rewarded with milk. If 
they touched the other painting (Mondrian's painting, 
45in this case), they would not receive milk. If mice 
are capable of discrimination, they should touch the 
painting associated with the milk reward (Experiment 
2).
The first experiment, in which a slide show program 
50on the iPod displayed 10 paintings each of Kandinsky 
and Mondrian to the mice, did not indicate a longer 
staying time for either artist's paintings. Analysis of 
individual mice revealed only one mouse out of the 
twenty stayed longer near Kandinsky's paintings. The 
55mice did not indicate a preference for Picasso or Renoir 
either, although one mouse out of the twelve stayed 
longer near Renoir's painting. In the experiment which 
used morphine (conditioning in Experiment 1), mice 
stayed longer at the painting shown to them after the 
60morphine injection for both the Kandinsky/Mondrian 
and Picasso/Renoir pairs. In short, they were able to 
discriminate between the paintings. When mice were 
shown a number of the 10 paintings after the morphine 
injection (e.g. five Kandinsky paintings), they recorded 
65a longer staying time with the remaining paintings of 
the same artist, even when those paintings had not 
previously been shown to them (e.g. the five remaining 
Kandinsky paintings). This is a phenomenon called 
generalization and indicates that the mice were able 
70to categorize a certain style of painting into a group. In 
the touch screen experiment (Experiment 2), once mice 
could correctly discriminate the pairs of Kandinsky and 
Mondrian paintings, they were trained with different 
pairs. After repeating this four times, mice were able 
75to correctly choose the artist's painting in pairs of 
paintings never shown to them around 80% of the 
time. However, when the paintings were switched to 
Picasso-Renoir pairs, the mice were unable to choose 
correctly. This means that the mice were discriminating 
80or categorizing a painting style as a single group.
Among mammals, humans place importance 
on their sense of sight. Birds generally have excellent 
vision. Mice have excellent senses of smell and hearing, 
but it has been thought that they are non-visual 
85animals. This is understandable considering the fact 
that mice are nocturnal and burrowing creatures. This 
experiment demonstrates that mice have much better 
visual perception abilities than previously thought. 
Additionally, it means that perception of complex visual 
90stimuli like paintings extend to non-human animals.

Which choice is an underlying assumption Professor Watanabe makes regarding "staying time?"

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