Does increasing category structure complexity increase classification learning difficulty?

In
your lab classes, you participated in an experiment in which you were required
to categorise amoeba-like stimuli based on their internal features (i.e., the
organelles). Classification learning difficulty was varied between conditions.
The features relevant to this categorisation decision were not revealed to you,
so you were required to learn how to correctly classify the stimuli from the
feedback you were given.

This
experiment is a partial replication of one by Shepard et al. (1961), who
explored how different types of category structure affected classification
learning. In their first experiment, Shepard et al. (1961) demonstrated that
learning difficulty increases with category structure complexity. Our
experiment was designed to test the reproducibility of this result using more
confusable stimuli.

In
your tutorials, we described Shepard et al.’s (1961) first experiment and
contrasted their design with that of our experiment. In your lab report, your
task is to demonstrate an understanding of Shepard et al. (1961)’s original
experiment and findings, citing other relevant literature where appropriate to
explain their results. In doing so, you should provide a rationale for the
current study that justifies our predictions. You will also need to report the
results from the lab report experiment and discuss your findings in the context
of Shepard et al.’s (1961) results and the broader classification literature.

A
template for writing the lab report, including the method section, is available.
Note that, while the method is not assessed, you are still expected to complete this
section by replacing the missing values with the appropriate numbers.

The Study

The aim of our study was to perform a partial replication of

Experiment 1 from Shepard et al. (1961) using the amoeba
stimuli

from Blair et al. (2009)

The stimulus dimensions we used were more abstract and did
not