Sharon extinguished her dog's response of salivating every time the electric can opener was used. However, she noticed that after the can opener had not been used for several days, the dog salivated at the sound of the can opener. This situation represents the phenomenon of .

The development of simple stone tools by early hominids led to the ability to procure meat more efficiently. this in turn led to the change in diet that included larger amounts of protein. many scholars believe that this shift in diet was a significant part of how our ancient ancestors adapted so quickly to a varied set of environments, and thus were able to begin cultural development. this demonstrates the intimate connection between