Previous research has demonstrated that contextual information can produce a confirmation bias for degraded audio recordings. For example, Lange et al. (2011) showed that participants who learn that recorded statements are taken from criminal suspect interviews misinterpret innocuous degraded audio recordings (e.g., “Next thing I knew, there was mud everywhere”) as incriminating (e.g., “Next thing I knew, there was blood everywhere”). Additionally, when participants receive written transcripts of the recordings that contain incriminating errors, they are even more likely to misinterpret the innocuous recordings as incriminating. However, we do not know the mechanism underlying confirmation bias in these cases.
We believe that at least one of the mechanisms that likely contributes to confirmation bias in cases involving degraded audio evidence is fluency misattribution. Fluency refers to the speed or ease with which an individual processes a stimulus (Jacoby & Dallas, 1981; Whittlesea, 1993). While there are various features that can increase the fluency of a stimulus (e.g., clarity), people often do not realize why the stimulus was processed fluently. Thus, they may misattribute the ease with which they processed a stimulus to another judgment (fluency misattribution). For example, we believe that contextual information should make a context-consistent interpretation of the recordings (e.g., this recording is incriminating) come to mind more easily than an alternative interpretation. Consequently, individuals may misattribute the ease with which a context-consistent interpretation comes to mind as evidence that it is the correct interpretation of the degraded audio. Thus, the goal of this study is to determine whether fluency misattribution underlies confirmation bias in cases involving degraded audio evidence. To test this, we will manipulate both perceptual fluency (i.e., the ease with which individuals process stimuli given manipulations to perceptual quality) and conceptual fluency (the ease with which individuals process the meaning of a stimulus). We will manipulate perceptual fluency by changing the degree to which the recordings are degraded. We will manipulate conceptual fluency by changing the amount of contextual information that participants learn.
We will present either non-degraded, minimally degraded, or moderately degraded audio recordings to test whether the degree to which the recordings are degraded affects participants’ perceptual fluency, or the ease with which they interpret the recordings. Additionally, participants will either receive no contextual information about the recordings (no context), learn that the recordings come from wire-tapped conversations with criminal suspects that have been used as evidence in a criminal case (criminal suspect), or receive written transcripts of the recordings that contain incriminating errors (written transcripts). Thus, we will investigate whether the amount of contextual information available affects participants’ conceptual fluency, or the ease with which they process the meaning of the audio recordings. The degree to which participants exhibit confirmation bias should depend on the extent to which the audio recordings are degraded, as well as the amount of contextual information participants have to base their interpretations upon.