9.2 Sex differences in learning processes of rats  (Page 9/9)

According to evolutionary theory, the development of sex-differences in spatial ability can be predicted in species in which one sex’s range is different from the other sex’s range. This model holds for polygynous rodent species (including the laboratory rat), primates, and humans, to name a few. In such ancestrally polygynous species such as our own, males evolved to have higher working memory in order to find and remember the moving and depleting resources over larger ranges that are associated with hunting while females evolved to have a higher reference memory that allowed them to find static resources associated with gathering.

Discussion questions

1. Why do scientists believe that spatial learning is more developed in males than females? How can we test this?
2. Can you think of some selective reasons why females perform better in the CEC memory retention, most operant tasks, and spatial memory tasks?

Glossary

• classical eyeblink conditioning (CEC) paradigm – a procedure in which an animal is exposed to a noise which is immediately followed by an aversive stimulation to the eyelid which causes the animal to blink; the animal eventually becomes conditioned to blink when it hears the noise, with or without the aversive stimulation (Dalla, 2009)
• denominated taxon – a learning strategy that involves repetition, animals remember and repeat the same set of movements to reach a goal
• estrus - The periodic state of sexual excitement in the female of most mammals, excluding humans, that immediately precedes ovulation and during which the female is most receptive to mating; heat.
• learned helplessness – this occurs when a subject learns that escape from an negative stimulus is impossible; the subject will move less and will have difficulty learning new escape strategies in new tasks
• local strategies – a learning strategy in which animals learn how to reach a goal through environmental, visual cues that surround the test site (for example the MWM)
• Morris water-maze (MWM) – most commonly used method to study spatial behavior, subjects are put into a pool of water and learn to find a non-visible platform using spatial cues around the platform; the water is typically made opaque with dye or beads so the animal cannot see the escape platform
• neurogenesis –the production of new neurons
• operant conditioning – a task in which an animal must make a response to learn; often they learn how to avoid or escape an aversive stimulus, such as a mild foot shock
• polygynous - a mating pattern in which a male mates with more than one female in a single breeding season
• proestrus - The period immediately before estrus in most female mammals, characterized by development of the endometrial and ovarian follicles
• thigmotaxis – a behavioral response when introduced to a new, possibly dangerous, environment that is best described as “wall-hugging”

References

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About the author

Vanessa Lippay was born on March 23, 1988 in Shamokin, Pennsylvania. There, she lives with her two parents, her younger brother, and three dogs. She received her undergraduate degree in 2010 from Rice University in Houston, Texas where she studied Ecology and Evolutionary biology and earned a B.A. in Biosciences. She plans on attending graduate school in the fall to obtain a Masters Degree in either Biology or Biomedical Sciences and eventually plans on going to medical school to become a physician. Her interests include film, her dog Bruce, dance, and travel.