Abraham Lincoln's wife Mary probably became interested in spiritualism sometime in the 1840s, when the widespread interest in communicating with the dead became a fad in the Midwest. Mediums were known to appear in Illinois, gathering an audience and claiming to speak to the dead relatives of those present.
By the time the Lincolns arrived in Washington in 1861, an interest in spiritualism was a fad among prominent members of the government. Mary Lincoln was known to attend seances held at the homes of prominent Washingtonians. And there is at least one report of President Lincoln accompanying her to a seance held by a "trance medium," Mrs. Cranston Laurie, in Georgetown in early 1863.
Mrs. Lincoln was also said to have encountered the ghosts of former residents of the White House, including the spirits of Thomas Jefferson and Andrew Jackson. One account said she entered a room one day and saw the spirit of President John Tyler.
One of the Lincoln sons, Willie, had died in the White House in February 1862, and Mary Lincoln was consumed by grief. It's generally assumed that much of her interest in the seances was driven by her desire to communicate with Willie's spirit.
The grieving First Lady arranged for mediums to hold seances in the mansion's Red Room, some of which were probably attended by President Lincoln. And while Lincoln was known to be superstitious, and often spoke of having dreams that portended good news to come from the battlefronts of the Civil War, he seemed mostly skeptical of the seances held in the White House.
One medium invited by Mary Lincoln, a fellow calling himself Lord Colchester, held sessions at which loud rapping sounds were heard. Lincoln asked Dr. Joseph Henry, the head of the Smithsonian Institution, to investigate.
Dr. Henry determined that the sounds were fake, caused by a device the medium wore under his clothes. Abraham Lincoln seemed satisfied with the explanation, but Mary Todd Lincoln remained steadfastly interested in the spirit world.