Sunday, October 4, 2009


This summer at the University of Iowa, I got the opportunity to work in a Psychology Lab. Initially, I thought of psychology as humans emotions and feelings, so imagine my surprise when I discovered I would be working with pigeons the rest of the summer. Although I was worried at first, the experiment proved to be interesting and brought up some thought provoking questions. An explanation of the experiment follows:

Our world is occupied with a variety of different objects, and what helps us organize these objects is categorization. In this experiment, we will see if pigeons are able to recognize identical and nonidentical members as belonging to the same category. Categorization allows us to understand the similarities and differences between different groups of objects. If we learn the category “chair,” for example, we can behave appropriately when we encounter a new chair, even if we have never seen it before. We are able to recognize members of the same category because they share some similarities. Recent studies show that categorization is not limited to humans; it may also be present in non-human species. Pigeons will be presented with three categories (dogs, fish, and flowers) with six different pictures in each category. The birds will have to perform a matching-to-sample (MTS) task in which they are first presented with one of the pictures (the sample) and then with three possible choices. Their task is to choose the one that “matches” the sample. Half of the times the correct choice will be identical to the sample (identity trials), and half of the times the correct choice will be a nonidentical member from the same category (category trials). There are four birds and each bird will complete ninety trials each day (forty-five category trials and forty-five identity trials). We will analyze pigeons’ accuracy on both identity and category trials, to see what type of task is easier for them. We expect that the identity trials will be easier because the sample and choice share all of the same features, while in category trials they only share some features. The results show a gradual accuracy improvement in all four birds over the span of two weeks. However, there is no apparent difference between the identity and category trials, which disproves our hypothesis. Therefore, this experiment shows that pigeons are capable of completing category trials as well as they do identity trials.

Yes, some complex stuff. I was a little overwhelmed at first, but eventually I understood the objective of the experiment. And the results were a bit surprising. We were expecting a better score for the identity trials, because obviously, they should be easier. However, there was not. In fact, this experiment is still being conducted at the University of Iowa, and there is no drastic difference between the category and identity trials. This makes psychologists wonder if this is just luck, or if pigeons really are capable of learning both categorical and identity trials. The next step would be to test this out on humans to learn more about matching to sample.

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