At the CNS meeting last March in San Francisco, I learned a new term during Marcia Johnson’s Fred Kavli Distinguished Career Contributions Award lecture: reality monitoring. Coined by Johnson, reality monitoring refers to how we distinguish what is real from what is imagined in our everyday lives. For some people, having an impairment in this seemingly basic ability can be devastating: It shapes our entire perceived reality.
Reality monitoring improves across childhood as frontal brain functions develop, Johnson explained at the CNS meeting, but for some – like patients suffering from schizophrenia or other disorders that induce hallucinations – those functions are impaired. A new review paper in Trends in Cognitive Sciences explores recent findings on reality monitoring for both clinical and non-clinical populations.
I spoke with the paper’s lead author, Jon Simons of the University of Cambridge in the UK, about the paper – including the motivation for the review, how reality monitoring errors may be linked to unconscious plagiarism, and cognitive training techniques that could one day help people suffering from hallucinations.
CNS: How did you become personally interested in this research area?
Simons: I’ve been interested for a long time in how we figure out where our memories originate from and, in particular, how the brain distinguishes real from imagined experiences. Like many people, I can be prone to daydreaming – usually when I should be doing some tedious administrative task – but I rarely mistake my daydreams for reality. How am I able to tell them apart?
CNS: How do you define reality monitoring?
Simons: Reality monitoring is the name that the doyen of research in this area, Marcia Johnson, gave to the processes involved in distinguishing between real and imagined events. Marcia’s hugely influential work over several decades identified that mental experiences don’t come with tags that specify them as real or imagined, but that we make judgements about their origin by considering their features in the light of what we expect real and imagined experiences to be like.
For example, we might expect memories of real events to be full of perceptual details, whereas imagined events might comprise traces of internally generated thoughts to a greater degree. We can use these heuristics to judge whether an experience is likely to have been imagined or to have actually taken place in the outside world.
CNS: What insights were you seeking in the review paper?
Simons: This review paper was a wonderful opportunity for my colleague Jane Garrison and I to work together with Marcia, which was a tremendous pleasure, as she is such an engaging and inspirational person to interact with. We aimed to provide an up-to-date overview of recent advances in understanding of the cognitive and brain mechanisms that underlie reality monitoring abilities, and the way in which they may be disturbed in health and disease. In synthesizing these findings, we sought to consider how reality monitoring errors might be linked not just with the hallucinations that are traditionally associated with psychiatric disorders but also with similar anomalous experiences that are increasingly recognized as occurring in the general population as well.
CNS: What are some of the psychiatric disorders and non-clinical situations in which reality monitoring is a challenge?
Simons: Disturbed reality monitoring provides a helpful account of the hallucinations and delusions experienced by many people with schizophrenia, who might imagine a voice but misattribute it as real. It can similarly explain symptoms of visual hallucinations in Lewy Body Dementia, the second most common form of dementia after Alzheimer’s. In the non-clinical domain, reality monitoring errors might underlie instances of cryptomnesia or unconscious plagiarism, where a thought one believes to be original was actually encountered elsewhere. Several famous cases of alleged plagiarism have been attributed to cryptomnesia, such as those involving Helen Keller and George Harrison.
CNS: What experimental and research advances have allowed for a better understanding of reality monitoring?
Simons: Recent years have seen a number of labs combine clever cognitive tasks with functional or structural brain imaging methods to explore the relation between reality monitoring and hallucinations. Growing evidence highlights the importance of anterior prefrontal cortex (a region at the very front of the brain, just behind the forehead) to reality monitoring.
Among the insights to emerge from this work has been a better understanding of whether a common brain basis, which includes anterior prefrontal cortex, might underlie disrupted awareness of what is real in neurological, psychiatric, and developmental disorders, as well as in healthy people who might hear voices but do not seek professional help or receive a clinical diagnosis.
CNS: In looking at the body of literature on this topic, what struck you the most?
Simons: One thing that struck us in working on this paper was how there has been comparatively little research into the experience of non-clinical voice hearers, a fascinating group with the potential to provide valuable insights into reality monitoring and hallucinations. This is why interdisciplinary research projects such as hearingthevoice.org, which seek to examine hallucinations from many different perspectives, are so important.
We hope that after reading our review, people will share our feeling that reality monitoring is one of the most fascinating topics in cognitive neuroscience.
CNS: How can current cognitive neuroscience research on reality monitoring be applied to cognitive training techniques or rehabilitation? Are there any examples of this yet to date?
Simons: There have been a few tantalizing hints that reality monitoring impairments might be at least partly ameliorated by cognitive training, brain stimulation, or neurofeedback. For example, a small study by Karuna Subramaniam in 2012 found that intensive training on cognitive tasks improved reality monitoring performance in 15 people with schizophrenia. If such improvements could be shown to reduce the incidence of hallucinations, then such interventions might have significant benefit. However, these developments are at a very early stage and further research involving properly controlled trials in larger samples is required before it can be determined whether these methods have real potential.
CNS: What do you most want people to understand about this work?
Simons: We hope that after reading our review, people will share our feeling that reality monitoring is one of the most fascinating topics in cognitive neuroscience. Understanding the processes than enable us to keep track of what is real, and establishing how they are organized in the brain, are objectives on which real progress has been made in recent years. However, there is much work to do before we can claim to fully understand how anterior prefrontal brain circuits support reality monitoring and are implicated in hallucinations.
CNS: What’s next for this line of work?
Simons: In the review paper, we outline a number of outstanding questions, such as: whether functional brain activity differences associated with reality monitoring impairment might have a basis in the underlying structure of the brain, whether such brain markers may be similar in clinical and non-clinical individuals who hallucinate, and, indeed, whether the hallucination experiences of these groups are similar or different. Working to answer these questions will keep researchers occupied for some time to come yet.
-Lisa M.P. Munoz