Secondary Task Interference with Free-recall of Event Elements; Related and Unrelated Event Element Lists
8.1 Introduction
In the previous expehnnents, the verification failure of supervisory systems in distinguishing the object category items presented in paired associate lists was assessed in terms of intrusion errors in a standard verbal learning paradigm. However, as discussed in Chapter 1, it has been suggested that the most dramatic failure of supervisory verification operations is observed in the confabulating patients who produce accounts of events that did not happen when they are asked about their past (Talland, 1965, Burgess & Shallice, 1996). Confabulation is seen as more of a retrieval problem than a storage or an encoding one. Burgess & Shallice (1996) argued that minor examples of the kinds of retrieval failure observed in confabulating patients commonly occur in the normal retrieval of events. Burgess & Shallice's study with normal subjects is one of the few studies done on this issue, which showed that when normal subjects recall events on a specific topic (e.g. the last time they visited the coast), they often use verification procedures to recognize and reject the elements/parts of elicited events similar to the one they are asked to recall (e.g. other holidays to the coast). As stated in Chapter 1, they have identified three types of failure in the three stages of retrieval; target description processes, verification processes, and mediator processes and also supported the key aspects of Norman & Bobrow's (1979) retrieval model.
One shortcoming of autobiographical studies is that, even though Burgess & Shallice's (1996) subjects, when asked to listen to their retrieval protocols, made corrections to the events they had previously remembered, there is generally no way to check whether or not they did in fact produce the correct event or confused it with the similar ones. In fact, it has been accepted that
autobiographical memories are never true and that they always contain distortions or incorrect but sensible-event-elements (Conway, 1990). There are some autobiographical studies which support this view. For example, the well documented Watergate testimony of John Dean showed how he was inaccurate in reporting many details and event sequences when his testimony was compared with the tape recordings of the conversations in the White House office (Neisser, 1981).
Besides the autobiographical studies, the inaccurate remembering of experiences has also been studied by using artificial events. The main interest of these studies was eyewitness testimonies and particularly these researches were guided by situations that normally occur at the aftermath of an incident. For example, eyewitnesses are likely to have conversations with other potential witnesses or with curious people who may make some suggestions on what may or may not be involved in the incident. Moreover, in an initial inquiry officers may ask some questions and these questions may contain extra information or suggestions about the incident that the eyewitnesses have not actually witnessed. The information that an eyewitness has from other people is called post-event information. It has been suggested that eyewitnesses may confuse this kind of post-event information with what actually happened at the time of incident (Loftus and Hoffman, 1989).
As discussed in the section 2.4.2 in Chapter 2, Loftus et al (1978) and Loftus & Palmer (1982) studied the effect of misleading post-event information on memories of a short film (accident scene) and showed that subjects remembered the misleading information as part of the original film. They argued that the current post-event information replaces the original memory. However,
as extensively discussed in the section 2.4.2, Bekerian and Bowers (1983, 1984) rejected Loftus et al's suggestion and instead they put forward a retrieval-based explanation of incorrect remembering by using Norman & Bobrow's (1979) retrieval model. They argued that original memories are not lost but accessing an original memory depends heavily on the retrieval cues provided. They claimed that the retrieval cues are used to form a description which is then used to search memory until some match is made between the description and the features of a memory record. Therefore, if the description does not represent the critical features of the original memory, it can match an incorrect memory record. Thus, Bekerian and Bowers's (1983, 1984) position is in line with Burgess & Shallice's (1996) position that memory lapses or confusions result from the failure of the strategic operations at retrieval. In fact these positions were both influenced by Norman & Bobrow's (1979) retrieval model which was central to the discussion concerning the role of supervisory systems at retrieval, reported in Chapter 1.
A pilot experiment using artificial events (films) was conducted. The aim of the study was to create a situation where natural confusion of elements of some similar episodes could be observed. For this purpose, subjects were asked to watch a series of similar short films (3 concerning couple quarrelling and 3 social gatherings) and, then, they recalled the films in any order. Analogous to the two types of confabulations observed in patients (see the section 1.7.4 in Chapter 1), fantastic and momentary confusions were sought in the subjects' retrieval statements. If a statement was completely false and far from the content of all the episodes presented, it was counted as fantastic confusion. If the content of an episode was distorted or confused with the other episodes, this was counted as momentary confusion. In addition, sensible but untrue event elements that
cannot be classified as confusions because there is reasonable doubt were counted as errors (e.g. if an actor was said to have dark-hair, although he had blond hair and if there was not any other information which would indicate that the subject was describing a person in another episode, then this was counted as an error).
This study revealed few confusions but the ones that occurred were interesting. In Table 8.1, some examples are given. As it can be seen in the part of the original conversation depicted in Table 8.1a (see also Appendix VII, Episode 4), John, the male actor, asks the female actor whether or not she believes another man called Grant, who was the point of discussion between the couple, and she says that Grant was sick and John should know this better than anybody. As illustrated in Table 8.1b,c,d, three subjects distorted the meaning of the conversation. One subject stated that the female actor said that she was sick (Table 8.1b), the other two subjects stated that John, the male actor, was sick (Table 8.1 c,d). The term sick was also used in two different meanings: in Table 8.1b, it was used as an illness but in Table 8.1c it was used to refer to the belief that John is unstable and the woman actor feels disgusted about him.
T a b l e . 8.1. Extracts from the retrieval statements of the subjects________ a. Male actor (M): "And you believe Grant."
Female actor F ) : "I didn't say that."
M: "Sharline you actually believe h i m after everything that we have gone t h r o u g h ."
F; "He's very sick and you know that better than anybody." M: "Sharline, he set this whole thing up, he is desperate to destroy our marriage."
b. "...She was saying that she had been sick..."
c. "...She was saying that "you are sick John, everybody knows you are sick J o h n . .."
d. "...They were arguing about their marriage and she was saying that he was s i c k . .."
e. "...She goes down to phone and then she hea r d the door and opened the d o o r ..."
The attribution of an action, activity or an experience to a wrong participant has been discussed in the sentence comprehension literature. According to Implicit Salience Theory, the relative degree of attention given to two or more participants of an event varies, and people attribute greater causality to more salient participants than to less salient ones (Kasof & Lee, 1993). The attribution errors observed in this study were consistent with the implicit salience theory in that Grant about whom the couple was talking was less salient object since he was not actually in the scene and the state of being sick was attributed to the couple in the scene. An example of a fantastic confusion is given in Table 8.1e. The first clause, "she goes down to phone", is completely false for there was no scene involving a phone or any action scene concerning a female going down some stairs to phone, this was fantasized by the subject. The second clause "then she heard the door and opened the door" is from one of the couple quarrel episodes (see Appendix VII, Episode 3). The scene starts with a female opening the door but there was no scene concerning a doorbell ringing which was a sensible error made to complete the scene.
One of the few integrations of two episodes into one (momentary confusion) is illustrated in Table 8.2. It is the confusion of two party episodes. The subject starts with describing the setting of one party and mentions correctly that it was political and there was a poster, although an error is made about what was written on the poster (The actual poster said "vote for Faraday", not "Michael Faraday".). Then the subject starts talking about a conversation that took place in another party episode and the actions of the two men and the conversation passed between them were described correctly. After that the subject turns back to the first party and actually describes the action of the camera swinging to show the pool and thereby finds the correct actors for the setting, who were