Intruders in the Mind

In this post, Pablo López–Silva and Tom McClelland present their new edited book, Intruders in the Mind: Interdisciplinary Perspectives on Thought Insertion (OUP 2023).

Thought insertion is a rare delusion most often found among those suffering from schizophrenia. It is characterised by subjects reporting that entities have introduced thoughts or ideas into their minds. Although the structure of these reports shows similarities, the external agents that subjects identify are highly variable: some identify individuals such as celebrities or relatives; some identify groups such as aliens or the government; others identify objects like radios, houses or trees. In an oft-cited case, one patient reports ‘…thoughts are put into my mind like “Kill God”, it’s just like my mind working, but it isn’t. They come from this chap, Chris. They are his thoughts’ (Frith, 1992, p. 66). 

This delusion raises a host of philosophical questions about the phenomenology of thought, our sense of ownership and agency over our own thinking and the boundary between self and world. This then feeds into more concrete questions about what causes these delusions and how they can be effectively treated. Intruders in the Mind is the first edited collection dedicated to this under-explored phenomenon and brings together work from philosophers, psychologists and psychiatrists. The collection is divided into four sections that deal with different aspects of thought insertion.

The first section - ‘Characterizing Alien Thoughts’ - considers how best to describe and define thought insertion. Roberta Payne offers a revealing personal account of her own experience of schizophrenia, anchoring the collection in the lived-experience of those suffering from the delusion. Clara Humpston & Matthew Broome draw on patient experiences to shed new light on the question of whether delusions of thought insertion are best characterized as beliefs. Following a phenomenological approach, Aaron Mishara, Pablo López–Silva, Cherise Rose & Andreas Heinz explores the often-neglected physicality of inserted thoughts i.e. patients’ describing thoughts as inserted into their minds as having physical properties. 

Pablo López-Silva

In Chapter 4 Michelle Maisse draws on ecological psychology, enactivism and phenomenology in her account of thought insertion as a disruption to how affordances for mental action are disclosed to the subject. In the fifth chapter Sam Wilkinson explores the contrast between inserted thoughts and auditory-verbal hallucinations and, in Chapter 6, Jasper Feyaerts & Wouter Kusters propose that schizophrenia is characterised by an attitude of preoccupation with and reflection on the world that is deeply akin to the attitude to the world adopted by philosophers.

The second section - ‘Explaining Thought Insertion’ - targets the problem about the aetiology of thought insertion. Catherine Cazimir & Al Powers explore the mechanistic and neural commonalities between thought insertion and auditory-verbal hallucination. Pablo López–Silva & Álvaro Cavieres then look at the merits and limitations of a predictive-processing approach to thought-insertion. In Chapter 9 Kengo Miyazono proposes a two-factor account according to which thought-insertion involves both experiential alterations and cognitive alterations. 

In the tenth chapter, Emilia Vilatta also proposes a multi-factorial model. Synthesising a deficit approach and motivational approach, she offers a nuanced account of the causal role played by different elements in the production of inserted thoughts. Finally, Peter Langland–Hassan offers an alternative account of thought insertion. He characterizes the delusion as a form of persecutory delusion that requires a distinctive form of clinical intervention.

The third section - ‘Experimental and Therapeutic Approaches to TI’ - begins with a chapter by Elisa Brann, Eamonn Walsh, Mitul A. Mehta, David A. Oakley & Quinton Deeley who propose experiments that might be able to produce relevant alterations in experience under controlled conditions. In Chapter 13 Alice Pailhès, Jay Olson & Gustav Kuhn suggest that experimental research can draw lessons from the practice of magic, including how magicians putting thoughts into people’s minds. 

Kentaro Hiromitsu & Tomohisa Asai shed light on the neurobiological underpinnings of thought insertion by focusing on the role played by the cerebellum. Working at the interface of theory and therapeutic practice, Susana Ochoa’s chapter argues that schizophrenia involves metacognitive dysfunction and explores what this means for therapeutic interventions. 

Tom McClelland

The fourth and final section - ‘Beyond the Phenomenon’ - focuses on how thought insertion challenges entrenched assumptions regarding the ontology of thought. Jordi Fernández argues that the experience of owning one’s conscious state is the experience of being committed to the content of that state, suggesting that thought insertion is a disruption to that sense of commitment. 

In the the final chapter of the edited book, Johannes Roessler challenges the common ‘no-subject’ interpretation of thought insertion according to which subjects are aware of thoughts without being aware of themselves as the thinker of that thought. 

Taken as a whole, the collection yields much-needed insights into the perplexing phenomenon of thought insertion. Beyond this, it serves as a valuable example of how disciplinary boundaries can be broken down in the pursuit of a greater understanding of the mind.