Wednesday, 18 October 2006

Skydiving used to mimic effect of trauma on memory

Following a traumatic experience, people often have a persistent, yet strangely incomplete, memory for what happened to them. One explanation is that in times of hyper-arousal, such as during trauma, our attention becomes extremely focused on the most relevant details of what’s happening, thus impairing our memory for more peripheral aspects.

To test this idea, Tamara Cavenett and Reginald Nixon recruited a group of 70 skydivers. Half of them learned a list of words in the relative calm of the waiting room prior to a later jump, whereas the other half learned the words while 10,000 feet up in the plane, just before making their skydive. Some of the words were related to skydiving (e.g. parachute), others weren’t (e.g. lamp). The rationale was that the hyper-arousal experienced by the latter group would serve as simulation of the extreme arousal experienced during trauma.

As the researchers expected, at a test later in the day, the participants in the plane subsequently remembered just as many words as the participants in the waiting room. However, crucially, there was a difference in the kind of words most often remembered by the two groups. Compared with the participants who studied the word list in the waiting room, the participants who studied the list in the plane tended to recall fewer of the words that had nothing to do with skydiving, but they remembered more of the words related to skydiving. Recordings of the participants’ heartbeat confirmed the participants in the plane had experienced increased arousal while learning the words, whereas the other participants hadn’t.

The researchers said the findings could help explain the experiences of people who suffer trauma. “Selective processing of relevant details may explain the high incidence of vivid flashbacks and re-experiencing of the traumatic event. Additionally, the inattention to the irrelevant details may account for the overall incomplete and fragmented memory of the trauma often associated with the disorder [PTSD]”.
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Cavenett, T. & Nixon, R.D.V. (2006). The effect of arousal on memory for emotionally-relevant information: A study of skydivers. Behaviour Research and Therapy, 44, 1461-1469.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

4 comments:

Anonymous said...

This summary is a bit pointless unless we are explicitly told whether those in the waiting room remembered more non-skydiving words than the skydivers, or not. If the former, rather than being evidence for hyper-arousal wouldn't that be evidence of a context effect?

Rachel said...

We are explicitly told that the skydivers remembered fewer non-skydiving words than those in the waiting room. A control to test for your argument would be to repeat the study with a different activity that had lower levels of arousal, such as going out for a meal.

Anonymous said...

I am a skydiver who experienced a trauma in the form of an out of control impact with the planet. That was 1992, after about a year of recovery, I have added over 850 skydives. I have never experienced PTS but do have a different recall of the experience from those who were the first responders. The mind is an interesting organ, yes?
os D22216 - orangesky10@hotmail.com

Anonymous said...

It is unlikely that this is merely a context effect as both participants were about to skydive. Therefore, it is more likely that both were in the context and the only difference between the groups were the hyper-arousal levels. As the goal is to measure differences in memory during extreme arousal, ideally the groups would be differentiated based on arousal levels. To rule out the possibility of a priming (context) effect and ideally replicate the findings, it may be better to…
• have both participants be up in the plane but only one jumping (assuming only those jumping will be experiencing extreme arousal) or
• compare skydivers that have jumped many times vs. those who were 1st timers (assuming they have different arousal levels, which could be validated by their heart rate monitors)

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