Psychological Factors Influencing Eyewitness Testimony--Part One

I have done a couple of prior posts on eyewitness testimony (here and here). Christian apologists make a big point of saying the gospels are reliable and trustworthy historical records because there would have been eyewitnesses still around to counter any errors or misrepresentations in the documents. The most recent treatment of this subject from a conservative, evangelical viewpoint is Jesus and the Eyewitnesses: The Gospels as Eyewitness Testimony (2006) by Richard Bauckham, Professor of New Testament studies at the University of St. Andrews in Scotland.

Bauckham maintains that the gospels are reliable history because the accounts contained in them are either from eyewitness testimonies or very close to eyewitness testimonies. While there has been considerable debate in the scholarly community as to whether the gospels really do record eyewitness testimonies (e.g., an entire issue of the Journal for the Study of the Historical Jesus , Volume 6, Number 2, 2008 ), the point of a new article by Judith Redman is that even if the gospels do record eyewitness testimony, that is no guarantee of their accuracy ("How Accurate Are Eyewitnesses? Bauckham and the Eyewitnesses in the Light of Psychological Research,", Journal of Biblical Literature [Spring 2010]: 177-97).

Redman says that eyewitness memory is typically called autobiographical memory in the psychological literature. She writes:

Autobiographical memory has three major components: verbal narrative, imagery, and emotions. Autobiographical memories are often recalled as stories told to others. The images associated with them lead to the specific, concrete details that make them seem more accurate and believable, while the emotions associated with them can have profound effects on how effectively people can retrieve autobiographical memories. Remembering involves a three-stage process of acquisition (encoding), retention (storage), and retrieval. Changes in content can be introduced at all of these stages, and there are significant numbers of different factors that can cause these changes.

First, Redman deals with aspects of memory acquisition or encoding. This is how the eyewitness experiences the initial event and there are at least five variables that impact his or her ability to perceive the event accurately.

1. Expectations. What witnesses expect to see or hear can affect the way they perceive an event. Expectations can be shaped by culture, stereotypes, past experience, or personal prejudice. . . .

2. Type of fact. People tend to find it more difficult to remember things that they need to estimate such as height, weight, distance, numbers of people in large groups, and duration of activities or events. . . .

3. Event significance and detail salience or prominence. In order to remember something, a person needs to attend to it, and, since it is impossible for an individual to attend to all the stimuli in his or her environment at any given time, s/he selects those things to which s/he will attend, often unconsciously. . . .

4. The personality and interests of the witness. Both of these factors affect how significant and salient particular events and the details of those events are to a particular eyewitness. All people are better at remembering some things than others, but the strengths and weaknesses vary from person to person. . . . The personalities and interests of eyewitnesses will determine what each finds interesting, surprising, potentially important, and therefore more memorable . . . . Material pleasing to the witness is likely to be elaborated on while displeasing material is likely to be distorted . . . . Events that are very surprising and have a high level of importance or emotional arousal give rise to "flashbulb memories" that are especially vivid and appear to be frozen in time, as though in a photograph. People may have flashbulb memories of where they were and what they were doing when they heard about public events like 9/11 or the first moon landing, as well as similarly significant but more private events like the birth of a baby or the tragic death of a loved one. Eyewitnesses to Jesus' miracles and to his postresurrection appearances would be expected to have formed flashbulb memories of these events. Flashbulb memories are often considered to be exceptionally accurate, yet research indicates that, like other memories, they deteriorate over time and are not always as accurate as the person remembering thinks they are. Indeed, recent evidence suggests that flashbulb memories actually develop over the first week after the event, taking into consideration what is learned from discussion with others.

5. Observational point of view and perceptual adequacy, or how well the observer can see and hear what is happening.

All of the above 5 points are important in understanding the potential problems with eyewitness testimony and how inaccuracies can develop but #4 if of particular significance. Many apologists would maintain that the resurrection appearances would have been so unique and unexpected that the disciples would have retained vivid and precise memories of the events for their entire lives. But as Redman indicates, studies have shown that even these "flashbulb memories" can be unreliable in the details.

An important study which demonstrates this fact is by Charles Weaver III and Kevin Krug, "Consolidation-like Effects in Flashbulb Memories: Evidence from September 11, 2001," American Journal of Psychology 117 (2004): 517-30. They had 400 students at Baylor University fill out questionnaires on their recollection of the events of 9/11 at five different times: 1) within the first 48 hours; 2) after 1 week; 3) after 1 month; 4) after 3 months; 4) and after one year. They concluded:

Flashbulb memories are influenced by the consolidation that takes place during the first week or so after the flashbulb event. . . . Flashbulb memories are subject to the same laws as other episodic memories. Like Winningham et al. (2000), we assume that memories are not fully formed initially but take time to consolidate. During this consolidation processes, memories are especially malleable. Information can be added to the memories . . . . Even more likely, details can be lost. . . . as specific details are forgotten, they might be replaced with schema-consistent details. This would be exacerbated by the frequent telling and retelling of these memories (pp. 525-26).

Another such event was the Challenger disaster of 1986. Robert Burton describes a study that was done relative to how people remembered this event.

Within one day of the space shuttle Challenger explosion, Ulric Niesser, a psychologist studying "flashbulb" memories, asked his class of 106 students to write down exactly how they'd heard about the explosion, where they were, what they'd been doing, and how they felt. Two and half years later they were again interviewed. Twenty-five percent of the students' subsequent accounts were strikingly different than their original journal entries. More than half the people had lesser degrees of error, and less than ten percent had all the details correct (Prior to seeing their journals, most students presumed that their memories were correct).

Most of us reluctantly admit that memory changes over time. . . . So, seeing that your journal entries were different than your recollection a couple of years later shouldn't be surprising. What startled me about the Challenger study were the students' responses when confronted with their conflicting accounts. Many expressed a high level of confidence that their false recollections were correct, despite being confronted with their own handwritten journals. The most unnerving was one student's comment, "That's my handwriting, but that's not what happened" (On Being Certain, pp. 10-11).

These studies show that how one recalls an event, even a momentous event from the past, can change dramatically from the initial appraisal of the experience. In addition, as Redman pointed out, flashbulb memories actually develop over the first week after the event, taking into consideration what is learned from discussion with others . People talk about momentous events with other people who also experienced them. Descriptions from others influence how one remembers the event himself. Sometimes these other details get incorporated into one's own memory of the event and subsequently one believes that he saw the same details too.

I will continue this discussion in the next post.