Reduced impact of imagery processing on false autobiographical recollection: the effects of dynamic visual noise

ABSTRACT

Research has demonstrated that merely imagining an autobiographical event can bring about false memories for that event. One explanation for this is that imagination leads to the creation and incorporation of visual-imagistic information into the event representation. This idea was tested in two experiments in which visual-imagery processing was disrupted by the use of Dynamic Visual Noise (DVN). In Experiment 1, autobiographical memories that were rated as “known” and lacking in event detail were subsequently rated as more “remembered” following imagination. In Experiment 2, imagination led to improbable autobiographical events being rated as more believable and vivid. In both experiments, interfering with imagery processing by DVN reduced these effects. It was concluded that visual-imagistic processing plays an important role in altering the mnemonic status of autobiographical representations.

KEYWORDS:

• Imagination inflation
• autobiographical memory
• dynamic visual noise
• false memory
• episodic memory

Acknowledgements

The authors would like to thank Dr Steve Jachim for the construction of the Dynamic Visual Noise software used in this research. In addition, we would like to thank Kath Walmsley, Lara Shelley, Nicola Diggle, Rachel Russell and Lisha Dahyabhai for assistance with the collection of data for the experiments reported here.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. In Hyman et al. (1998) and Experiment 1 of the current paper, the distinction between remembering and knowing was treated initially in a dichotomous manner (generating memories that were either “remembered” or “known”) and later in a continuous manner (using the 7-point rating scale with 1 as known and 7 as remember). For readers familiar with dual-process models of memory this “cross-classification” and usage of such terms may seem unwarranted. This is because extant theorising about the basis of memory has treated these two forms of memory as qualitatively distinct (dual process) (Yonelinas, 20022002), or varying along a continuum of memory trace strength (single process) (Dunn, 2004).

However, the purpose of the current work (and Hyman et al., 1998) was not to demarcate between dual (vs. single) process accounts of memory. Rather, the initial memory generation and classificatory task, was to allow the production of different types of memory that varied in terms of the details that each contained. For a memory that is generated as “known” the rating of this will likely vary along a continuum depending upon the relative familiarity of the memory. Irrespective of this, the ratings will be more towards the “know” end of the continuum. This was the outcome in Hyman et al. (1998) and Experiment 1 of the present research.

For memories classified as “remembered” it might be conjectured that all ratings should be designated a maximum of 7 on the rating scale (because if a memory is indeed “remembered” and thus rich in episodic detail, then it should not receive a rating score of less than 7). However, remembering (recollection) is not necessarily an all or none process (Yonelinas, Aly, Wang, & Koen, 2010). Thus, individuals can remember more or less of the precise episodic details of an event and this will translate into variations in the responses on the rating scale; albeit with all such memories being rated as high on the response sale continuum (Yonelinas et al., 2010). This was likely reflected in Hyman et al. (1998) and Experiment 1 of the current work in which the mean of the “remembered” memories was less than 7 and rated as 5.79 (see the upper half of Table 1 in the result section).

2. Sample sizes were determined based on previous DVN research. The stopping rule was when we reached a minimum of 20 per-between subject group or the end of an academic year, whichever produced the most. The maximum was 30.

3. These analyses were not planned but were suggested by a reviewer. We performed these as it was felt that such relationships might prove to be of interest in the context of this and prior work on autobiographical memory.

4. For Experiment 2, this was partly precluded by the fact that the participant was listening to the recorded description of the events. Of course, it could have been possible to play the event narrative via headphones and record any verbal elaborations. However, doing this may have made the task unduly complex.