Haber and Levin found that participants were more accurate at judging the size of
token invariant objects objects that are nearly always the same size, like a coffee mug
compared to token variant objects, which vary more in size, like a Christmas tree. This
can partly explain why Zara was not able to accurately judge the size of half of the
objects she was shown. Some of the objects, such as the scaled down model of a
castle, would be token variant castles come in very different sizes in real life, so Zara
would have no fixed idea of how big one should be. This means she could not use
past experience to make an accurate size judegment.
The study also found that participants were better at judging the distance of familiar
objects, because they could use their knowledge of how big those objects normally
are to work out how far away they must be. This helps explain why Zara was accurate
in judging the distance of most of the familiar objects, like the coffee machine. Because
she had seen one many times before and knew roughly how big it is, she could use
that knowledge to estimate its distance.
However, Haber and Levins findings do not fully explain Zara's results. The study
focused on whether objects were token invariant or token variant, but it did not account
for other visual cues that might be available in a real setting — such as the floor, the
room size, or nearby objects. In Zara's study she was shown objects at different
distances from her, so these cues may have played a role that Haber and Levin did
not consider. This means the study may not explain the full picture of why Zara was
inaccurate.
Another limitation is that Haber and Levin used only male university students, which
means the sample is not very representative. Zara is likely to be a different type of
person, so the findings may not apply to her in the same way. This makes it harder to
use the study to fully explain her results.
Overall, Haber and Levin (2001) can explain Zara's findings quite well in some ways.
The idea that familiar objects are easier to judge for both size and distance fits with
the fact that Zara did well with familiar objects for distance but struggled with size more
broadly. However, the study cannot fully explain everything because it used a limited
sample and did not test the same conditions as Zara's study. So while the research is
useful, it only gives a partial explanation for her inaccuracy.