Four-year-old Zeena, the younger sister in the Alpine 'family feud' execution killings, is reported to being helped by a child psychiatrist. She endured eight hours cowering under the bodies of her parents and grandmother. This British family were on holiday in France when they became victims of what is currently suspected to be a family feud, and 'contract' style executions.

Apprehending the perpetrators of this dreadful crime is likely to turn on her eyewitness testimony.

But what impact is the trauma going to have on her mental state? The psychological issue has wider implications; memory of childhood sexual and other abuse, as well as other trauma, is vital in criminal prosecutions all over the world. Trauma's impact on childhood recollection has been described as the most controversial and heated issue in modern psychology.

Psychologist Carole Peterson, from the Memorial University of Newfoundland, Canada has just published the most up to date review of scientific research on this subject, in a paper entitled, Children's autobiographical memories across the years: Forensic implications of childhood amnesia and eyewitness memory for stressful events.

Peterson points out the current consensus amongst psychologists is the average age of earliest memory is 3½. While many claim earlier memories, in fact scientific research on adults shows little or no reliable recall for events before three to four years old.

Peterson reports a case before the England and Wales Court of Appeal involving a teenager's recollection of childhood sexual abuse from the age of four. Judges are now required to warn juries that memories from such ages are inherently unreliable. This is despite sounding convincing, so vehement debates over childhood amnesia continue in courtrooms all over the world.

Peterson, who interviews children about their earliest memory, found young children have much earlier recollections than adults do of their childhood. Two-year-olds can describe memories of personal events that happened months earlier. Yet, most of these reminiscences eventually become obscured over time.

While we still don't know why our memory becomes particularly unreliable as adults, for events before the age of four years old, Peterson points out highly negative events appear especially well-recalled.

For example, Peterson cites research that preschoolers recall 20-30% of the features of a living-room game - a camping trip - when interviewed by researchers merely one day or a week later, but fully 75% of facial surgery following an injury, over a year later. Counter perhaps to popular belief, Peterson's review concludes that childhood stressful events might be better recalled than less traumatic ones.

This does tend to cast a serious question over the whole Freudian theory of repressed childhood memories for awful experiences. Repression means our own childhood becomes a mystery to us, requiring the detective work of the hired analyst to uncover what really happened.

But the other problem, Peterson points out, is how forensic interviews are conducted has been shown to be crucial in extracting what a child recalls. Some psychotherapists defend finding repressed childhood memories by arguing therapy provided a uniquely safe environment. But do they in fact 'insert' a 'false' memory into a vulnerable adult through suggestion?

Forensic specialists investigating crimes have found that while focused questions seem to prompt more answers, compared to 'open' questions, these can generate unreliable recollections.

The way you ask a child to remember a traumatic event, determines the recollection you get back. So Peterson and colleagues have pioneered an interview technique for police and forensic experts interviewing child eye-witnesses, using 'key cards'. These could give the French police an edge leading to the apprehension of the perpetrators of this dreadful crime.

This technique prompts the child in a forensic interview, just as will probably happen for Zeena, who will likely be interviewed by forensic psychologist specialists. These cards cue the child to provide information about participants, setting, actions, and dialog with line drawings representing each category of information visually.

But another key finding from Peterson's own research is that how her own parents routinely talked to Zeena in the past, will have a major impact on what she can recall. This research finding, reported in Peterson's current paper just published in the academic journal 'Developmental Review', has important implications for parents everywhere.

Some routinely encourage their children to elaborate during conversation; they provide additional elaborative information in their own conversational turns. This encouragement and support for children's contributions fosters lengthier discussions of past events, rather than curtailing such exchanges. In contrast, other parents ask just a few standard questions about a prior event. There is little detailed exchange. An elaborative style of conversation involves returning to the topic in order to chew over and enjoy the details.

Considerable research confirms parental differences in the way children are chatted to predicts how much offspring later recall. Peterson's latest study confirms that even memories for highly stressful events are significantly improved if parents have taken an 'elaborative' style of conversation, with their children.

So if you want your kids to make better eye-witnesses of life, then elaborate more with them.