U.S. flag

An official website of the United States government, Department of Justice.

The Neuroscience of Evidentiary Rules: The Case of the Present Sense Impression

Award Information

Award #
Funding Category
Competitive Discretionary
Congressional District
Funding First Awarded
Total funding (to date)

Description of original award (Fiscal Year 2017, $49,898)

This study will employ neuroscientific measurements of brain activity to help formulate evidentiary rules that better reflect the realities of human cognition.

The current rules are premised on untested psychological assumptions. This research will test the assumptions underlying a provision of the Federal Rules of Evidence (FRE): the Present Sense Impression (PSI), codified as FRE 803(1) and adopted in 80% of states. The PSI is one of the exceptions to the ban against hearsay that have been adopted because it is believed that in specific circumstances, the risks of deceit and errors in memory and perception associated with hearsay are lessened. This belief, however, is premised on “folk psychological” assumptions that have never been tested.

This grant will test two of these foundational assumptions: (1) contemporaneity safeguards against deceit; and (2) listeners can better detect lies about contemporaneous than past events. Even when accepting these as true, courts have struggled to define the temporal limits of “contemporaneity.”

The researcher will use a combination of behavioral and electrical brain activity (the electroencephalogram or EEG) measures to assess these assumptions. Experiment 1 uses EEG recordings and a behavioral deceit paradigm to test two major hypotheses about the relationship between time and deceitful practices. First, distinct cognitive processes underlie lies about contemporaneous events, lies about past events, and truthful responses.

Second, at some time point, as the event and the telling of the lie become increasingly temporally divorced, the cognitive processes employed switch between those involved in contemporaneous and past event lies. This provides insight into when “contemporaneity,” if it exists, begins and ends.

Experiment 2 uses a behavioral paradigm to test the difficulty of spontaneously lying compared to reciting a premeditated lie or responding truthfully. Participants will narrate videos and be prompted to be truthful, recite a pre-instructed lie, or generate a spontaneous lie about specific aspects, such as changes in the actor or action. Frequency and success rate will be compared across conditions.

Experiment 3 assesses whether third-party listeners are better able to detect contemporaneous lies compared to past-event lies. Experiment 2 recordings will be played to listeners who will rate the responses as truthful or deceitful, and detection rates will be compared across conditions. Thus, the three experiments in this project will test each of the tenets that the PSI exception is built on.

By empirically testing the assumptions underlying the FRE, neuroscience can facilitate evidentiary rules that better reflect human cognition.


Date Created: September 6, 2017