Experimentally inducing dreams of remote emotional memory

Activating a remote emotional memory just before sleep can induce dreams about that memory. In a study with 34 participants, those who recalled and wrote about an emotionally negative remote memory before a daytime nap later had dreams judged to contain content from that memory more than from a control task. Participants also rated their dreams as more emotionally negative after the memory task. The findings suggest that dream content can be experimentally influenced by reactivating older memories, possibly reflecting memory reconsolidation during sleep.

Study at a glance

Abstract

Abstract People frequently dream of recent experiences, which may reflect the consolidation of memories in the sleeping brain. Many studies demonstrate that experimentally introducing new learning prior to sleep can induce dreams of recently encoded memories. Here, for the first time, we tested whether activating a remote memory just before sleep can similarly induce participants to dream about the remote past. Participants (N = 34) completed an Autobiographical Emotional Memory Task (AEMT), in which they recalled and wrote about an emotionally negative remote memory prior to a daytime nap. In a control condition, participants instead wrote about designing a new college course. As hypothesized, the AEMT induced emotionally negative dreams related to the remote memory activated before sleep. Specifically, according to judge ratings, dreams incorporated content from the remote memory recalled during the AEMT to a greater degree than they incorporated content from the control task. While participants themselves did not perceive their dreams as more strongly related to the AEMT memory than the control task, they did rate their dreams as more emotionally negative following the AEMT. This shows it is possible to experimentally induce dreams of a specific remote memory by activating it before sleep. These findings are discussed in light of the hypothesis that dream content might be influenced by the reconsolidation of recently reactivated remote memory. Statement of Significance This research is among the first to experimentally study how dreams incorporate remote memories from the long past. This is important because sleep may function not only to stabilize recent memories, but also to update older memories with newly learned information. Studying the appearance of remote memories in dreams may provide a window into how the process unfolds in the sleeping brain.