Due to the quick loss of potentially valuable facts in human memory, we must
sometimes tap into digital devices to retrieve critical case information.
Legal proceedings often rely on human memory for events and the sequence of those events. Studies have
shown that individuals are notoriously bad at remembering details about past events. Without replenishing
or review of perceptions, neural traces in the brain degrade and information is lost. Digital forensic investigations have played a pivotal role in many highly publicized cases and those same forensic techniques can
be applied to recreate seemingly routine events that humans typically forget. This article will examine how
the use of digital forensics can aid the legal profession
with fact finding to support or refute eye witness testimony involving details of events.
The decay curve that models the human mind
related to the amount of forgotten facts is initially a
very steep logarithmic function and shows how many
natural processes, such as radiation, diminish with time;
it is ubiquitous throughout science.1
Digital devices, however, are very good at “
remembering” such otherwise forgotten details. A modern
analysis of digital devices is commonly overlooked as
a source of important and case-changing information.
Because of the quick loss of potentially valuable facts,
attorneys, law enforcement, and investigators must
sometimes use a forensic digital examiner to tap into
digital devices and retrieve critical information. Digital
forensic capability is explored herein after the human
memory ability is briefly reviewed and modeled.
The Basic Hypotheses
Psychologists have approached the subject of forgetting
in various ways. Psychologist Donald O. Hebb first
applied a decay curve formula to memory loss. 2 Memories certainly fade over time, but how quickly the details
about past events fade differ from individual to individual. Several studies support this rapid-loss-of-information model. 3-5 Among many hypotheses, two fundamental representations exist to determine the decline in recollection of events. The first considers that
there is no correlation between the amount of information or number (N) of facts learned and the time
frame (t) over which it is forgotten.1 According to the first model, it does not matter if someone is given
10 or 20 items/facts (N) to remember—the rate by which it is forgotten remains constant.
The second hypothesis asserts that the amount of original information learned does indeed have an
effect on how quickly information is forgotten over time. 6 In the example above, the 20-item learning set
typically, yet counterintuitively, results in a longer memory retention period than the 10-item set. In this
article, the second hypothesis is accepted and used.
As Figure 1 shows, the loss of information happens exponentially from the time an event occurs.7 In
this example the item set (N) of 20 and a delay of three days (t) is assumed. The result is a loss of 77.7% of
Skeletons in Your Client’s “Digital Closet”
Figure 1: Hypothetical forgetting curve based on
Geoffrey R. Loftus’ (1985) paper “Evaluating Forgetting Curves” 4