article_snippet.sent: In some of we earlier studies, we found that people selectively remember neutral pictures if the pictures had been associated with an electrical shock the previous day, even when the volunteers were unaware that we would later test the volunteers memory, the volunteers wrote.
article_snippet.sent: we have also shown that people remember neutral pictures if people are warned that if people forget people, people will receive a shock the next day.
article_snippet.sent: Likewise, being rewarded with money for remembering certain pictures the next day can boost memory for certain pictures the next day as well.
article_snippet.sent: Volunteers viewed a series of trivial pictures from two categories, either animals or tools.
article_snippet.sent: After a delay, volunteers were presented with a new set of animal and tool pictures – only this time, when the volunteer saw the pictures the volunteer received an electrical shock to the wrist.
article_snippet.sent: we already knew that memory would be strengthened for the pictures paired with an electrical shock.
article_snippet.sent: But here we found that if we paired shocks with pictures of animals, memory was strengthened for pictures of animals volunteers saw before any shocks were delivered.
article_snippet.sent: If we shocked volunteers when volunteers where shown pictures of tools, memory for the earlier pictures of tools was strengthened.