We often offload memory demands onto external artefacts (e.g., smartphones). While this practice allows us to subvert the limitations of our biological memory, storing memories externally exposes them to manipulation. To examine the impact of such manipulation, we report three experiments, two of which were pre-registered. Individuals performed a memory task where they could offload to-be-recalled information to an external store and on a critical trial, we surreptitiously manipulated the information in that store. Results demonstrated that individuals rarely noticed this manipulation. In addition, when individuals had information inserted into their external memory stores, they often encoded it into their biological memory, thereby leading to the creation of a false memory. The reported results highlight one of the cognitive consequences of offloading our memory to external artefacts.
Humans have long sought to offload demands on their memory by using external artefacts (Clark, 2010a; Donald, 1991; Nestojko, Finley, & Roediger, 2013; Risko & Gilbert, 2016). Nevertheless, we lack a deep understanding of the principles governing this distributed form of remembering. The recent proliferation and increasing availability of mass storage devices presents our species with a remarkable opportunity to store large amounts of easily accessible information that is immune from the vicissitudes of our biological memory; however, offloading memory creates its own set of risks (Carr, 2008; Eskritt & Ma, 2014; Risko & Gilbert, 2016; Sparrow, Liu, & Wegner, 2011). One such risk is that offloading memory to an external location exposes it to manipulation by a third party (Clark, 2010b; Sterelny, 2004). For example, an agent could surreptitiously alter our “memory” by manipulating the information in our external memory stores. Understanding how individuals respond to this kind of manipulation would provide insight into how individuals manage the unique challenges presented by distributing memory demands over internal and external spaces (e.g., transactive memory systems; Arango-Muñoz, 2013; Ferguson, McLean, & Risko, 2015; Gilbert, 2015a, 2015b; Risko, Ferguson, & McLean, 2016; Risko & Dunn, 2015; Sparrow et al., 2011; Ward, 2013; Wegner, 1995; Sutton, Harris, Keil, & Barnier, 2010; Storm, Stone, & Benjamin, 2017). Provided the ubiquity of offloading as a means of remembering, understanding our susceptibility to external memory manipulation, the factors that modulate it, and the impact of such manipulation on our biological memory is needed. To this end, we report three experiments examining external memory manipulation using a novel paradigm. In the context of a distributed cognitive system, individuals face various challenges (Arango-Muñoz, 2013). This includes deciding whether to solve a cognitive problem relying on internal resources or external resources (or a mix of the two; i.e., the “selection” problem; Arango-Muñoz, 2013). Much recent work has focused on this aspect of cognitive offloading (i.e., how do we decide to offload to-be-remembered information rather than store it internally; Cherkaoui & Gilbert, 2017; Gilbert, 2015a, 2015b; Risko, Medimorec, Chisholm, & Kingstone, 2014; Risko & Dunn, 2015; Risko & Gilbert, 2016). In addition to deciding whether to rely on an external resource, individuals also have to decide whether to rely on or “endorse” the information provided by that external resource (i.e., the “endorsement” problem; Arango-Muñoz, 2013). For example, in a memory context, if an individual stores some to-be-remembered information in an external location, at the time of retrieval from that external store, the individual needs to endorse that information as the original to-be-remembered information. Previous research suggests that individuals may have great difficulty detecting manipulations of their external memory stores or, in other words, solving this endorsement problem.