The Effect of Suggestibility on Metamemory Judgements and the Moderation of Individual Differences and Emotions

Abstract

How do we determine whether something we do not remember occurred? Prior research suggests that people rely partially on memorability judgements: when a non-remembered event seems memorable, we infer that it did not happen, but when the event seems unmemorable, we might infer that it happened and was forgotten. In the present research, I examined whether people’s judgements of memorability could be susceptible to suggestion in the form of false feedback and whether pictures’ memorability, individual differences, and emotional factors moderate this false feedback effect. I conducted seven online picture-memory experiments (five preregistered; total N = 2600), wherein participants first encoded pictures and then completed a test containing old and new pictures. Some of the test pictures were accompanied by feedback specifying whether the picture was old or new; however, for a small number of the new pictures, this feedback falsely claimed that the picture was old. Participants rated the familiarity and memorability of each picture and made judgements of learning. Across five individual experiments and two complementary mega-analyses, results consistently showed that receiving false ‘old’ feedback led participants to rate new pictures as more familiar but less memorable compared to new pictures with no feedback. Moreover, the false feedback had a stronger influence on people’s metamemory judgements of pictures that were normatively more memorable than for less memorable pictures. However, individual differences and emotional factors did not significantly moderate this effect. Together, these findings provide the first evidence that false suggestions can subtly shift people away from reasoning “I’d remember this, if it had happened” toward reasoning, “I don’t remember this, so it must be forgettable”. This work advances theoretical understanding of the false feedback effect on metamemory judgements and has important implications for educational and legal contexts.

Date of Award	Mar 2026
Original language	English
Awarding Institution	Aston University
Supervisor	Charlotte Rebecca Pennington (Supervisor) & Robert A. Nash (Supervisor)