The role of confirmatory interviewer feedback
As we have seen, one consequence of confirmatory interviewer feedback is that it leads participants to discount their uncertainty in their fabricated responses, such that it increases false memory for fabricated events and leads participants to endorse witnessing fabricated items with the same speed and confidence that they endorse actually witnessed items. In a recent unpublished study (Rich & Zaragoza, 2016) we assessed whether confirmatory interviewer feedback would also catalyze false memory development in situations where participants are forced to fabricate entire fictitious events. A clear finding was that confirmatory interviewer feedback accelerated the development of false memory for event fabrications, even when participants were warned prior to taking the test. Although prior event fabrication studies have consistently shown that participants are resistant to false memory at short retention intervals, we found that, when participants received confirmatory interviewer feedback following their event fabrications, they evidenced reliable false memory effects at retention intervals of one week, even when participants were warned that they had been misled and even when the analysis was restricted to participants who did not remember the feedback.
The fabricated event’s explanatory role
One factor that contributed to the high level of false recall in the experiments involving event fabrications is the explanatory role these fabrications served (see Chrobak & Zaragoza, 2013). In all of the experiments where we have forced participants to fabricate entire fictitious events, participants’ fabrications served an explanatory function, in that the fabricated accounts helped to provide a more complete explanation for an outcome they had witnessed. For example, as described earlier, some participants were pressed to fabricate a fictitious prank that caused Delaney to fall to the floor in the dining hall. Relative to the events participants had witnessed (Delaney losing his balance and falling), the events participants were forced to fabricate (a prank that precipitated the fall) provided a richer, more plausible, and more complete explanation of the events that caused the witnessed outcomes. Several pieces of evidence support the hypothesis that a fabrication’s explanatory role is one factor that contributes to false memory development. For example, Chrobak and Zaragoza (2013) showed that participants were less likely to develop false memories for their event fabrications when the explanatory strength of the fabricated account had been reduced by the presence of a potential alternative explanation for the same outcome (see Chrobak & Zaragoza, 2013, for additional evidence that supports this explanatory role hypothesis). Given that the purpose of forensic interviews is to seek an explanation for an adverse outcome (e.g., a crime or an accident), much of the information that witnesses are asked to provide serves an explanatory function.To the extent that this testimony is forced, its explanatory role is one factor that contributes to false memory development.