Once again, another study has connected sleep deprivation with cognitive function. And, it provides some good news and some bad news. The bad news is that if a party witnesses an event while sleep deprived, and then is asked later to recall the event while still sleep deprived, she will recall it inaccurately; that is, she will have a false memory of it. However, the good news is that if she witnesses an event while sleep deprived but is allowed to get some sleep so that the event can be encoded in her brain, and then is asked to recall what she saw, her memory will be more accurate.
In a study conducted by psychological scientist Steven J. Frenda of the University of California at Irvine with colleagues, as reported in Psychological Science on July 16, 2014, these researchers determined that, "....sleep-deprived people who viewed photographs of a crime being committed and then read false information about the photos were more likely to report remembering the false details in the photos than were those who got a full night's sleep." (Association for Psychological Science at p.1.)
To conduct the study, the researchers recruited 104 college age participants. They were assigned to one of 4 groups:
Two groups were presented with a series of photos depicting a crime being committed as soon as they arrived to the lab - one group was then allowed to go to sleep, while the other group had to stay awake all night in the lab. The remaining two groups did things in the reverse order - they either slept or stayed awake all night and then viewed the crime photos in the morning.
In the second part of the experiment, the participants read narratives containing statements that contradicted what the photographs actually showed. For instance, a text description might say that the thief put a stolen wallet in his pants pocket, whereas the photo shows him putting it in his jacket.
The researchers found that only those students who had been sleep deprived for all parts of the experiment - that is, they viewed the photos, read the narratives, and took the memory test after having stayed up all night - were more likely to report the false details from the text narrative as having been present in the crime photos.
The students who viewed the photos before staying up all night, however, were no more susceptible to false memories than the students who'd been allowed to sleep. (Id.)
Thus, there is now one more study that questions the accuracy of eyewitness testimony of or identifications by a person who is trying to get by on less and less sleep. If a person has been sleep deprived (for example, less than 5 hours a night) at the time of witnessing an event, even as mundane as an automobile accident, her memory as to what occurred may be far from accurate. That is, viewing something when one is in a very tired state will not make for an accurate memory of what was witnessed.
So... the next time the facts are in dispute or even if they are not, before accepting unquestionably the recollection of one of the parties as to what occurred, you may first want to ask her about how much sleep she was getting at the time she witnessed the event and then immediately afterwards. If the witness was very tired, or sleep deprived at the time of witnessing the event, her testimony may not be so reliable.
..... Just something to think about.