Do you have trouble getting started in the morning? Do you have problems learning early in the day? If you do, you are not alone. 31 They learn better at night than they do in the morning.
To investigate when cockroaches learn best, researchers at Vanderbilt University tested the insects for which odor (peppermint or vanilla) they preferred. Most cockroaches preferred the smell of vanilla to that of peppermint at all times. 32 Therefore, the scientists trained the cockroaches to prefer the peppermint smell by rewarding the insects with a taste of sugar water when they approached a peppermint smell. 33
When the cockroaches were trained at night, they remembered the new associations (peppermint = sugar water; vanilla = salt water) for up to 48 hours. However, if the cockroaches were trained in the morning, they quickly forgot which smell went with which water. 34
So, cockroaches learn better at night than they do in the morning. 35 Because of this, it is likely that information they gather at night will be more useful to them. These experiments provide some clues about the interactions between body rhythms, learning and memory.
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