delusions of reference: a new theoretical model

Delusions of reference: A new theoretical model

Mike Startup1, Sandra Bucci2, and Robyn Langdon3

1School of Psychology, University of Newcastle, Australia, 2School of

Psychological Sciences, University of Manchester, UK, 3Macquarie Centre for

Cognitive Science, Macquarie University, Australia, and Cognition and

Connectivity Research Panel, Schizophrenia Research Institute, Darlinghurst,

Australia

Introduction. Although delusions of reference are one of the most commonpsychotic symptoms, they have been the focus of little research, possibly becausethey have been considered to be integral to persecutory delusions. Evidence has nowemerged that there are two kinds of delusion of reference. One of these, referentialdelusions of communication, which involves beliefs that others are communicatingin subtle, nonverbal ways, is the focus of this paper.Methods. We present a new model designed to account for the four crucial aspects ofthe phenomenology of these delusions: (1) that neutral stimuli are experienced ashaving personal significance; (2) that the neutral stimuli are experienced ascommunicating a message nonverbally; (3) that the content of the message concernsthe self; (4) that the experience of a self-referent communication is believed ratherthan being dismissed as implausible. We used PsycINFO and Scopus, using the term‘‘delusion* of reference’’, to search for publications with a bearing on our model.Results. The amount of research we found that was designed to test aspects of thismodel is small but other published research appears to provide some support for itsvarious steps. Much of this research was not explicitly intended to provide anaccount of delusions of reference but its relevance nevertheless seems clear.Conclusions. There is preliminary support for the plausibility of our model but muchadditional research is needed. We conclude by summarising what we consider to bethe main desiderata.

Keywords: Aberrant salience; Delusions of reference; Reality discrimination;

Theory of mind.

Correspondence should be addressed to Mike Startup, School of Psychology, University of

Newcastle, Callaghan, NSW 2308, Australia. E-mail: [email protected]

We would like to thank Prof. Nick Tarrier for his comments on an earlier draft of this paper.

COGNITIVE NEUROPSYCHIATRY

2009, 14 (2), 110�126

# 2009 Psychology Press, an imprint of the Taylor & Francis Group, an Informa business

http://www.psypress.com/cogneuropsychiatry DOI: 10.1080/13546800902864229

Interviewer: Have you ever walked into a room and thought people were talking

about you or laughing at you?

Patient: Yeah, sometimes people have got sneering eyes. You can see it. Maybe

it’s a reflection of what I’m thinking in my head, you know what

I mean? You can see it in their eyes. It’s good to be self-conscious

’cause you can catch yourself out and correct yourself. But if it goes

too much you get paranoid in yourself. That’s when the carnival

starts. Oh yeah, that’s when the trickster comes in.

INTRODUCTION

Delusions of reference are said to occur when people mistakenly become

convinced that neutral events, objects, or people in the environment havespecial significance and contain personal relevance to the observer. Clinical

observations have primarily informed definitions of delusions of reference

that are contained in psychiatric textbooks (e.g., Gelder, Gath, & Mayou,

1989) and in semistructured interviews such as the Present State Examina-

tion (PSE; Wing, Cooper, & Sartorius, 1974). According to such sources,

some patients frequently have the mistaken belief that others are commu-

nicating with them by subtle and oblique paralinguistic means, such as

indirect hints or innuendos, or through nonverbal channels, such as gesturesor stances. They may also believe that they are being personally referred to in

the public media or that objects or situations have been purposely arranged

in order to convey a message. Some even have the sense that animals are

communicating implausibly complex messages to them. Other delusions of

reference concern beliefs about being kept under observation. For example,

some patients mistakenly believe that others are surreptitiously observing

them, perhaps by using surveillance equipment or by following them, or that

a large number of strangers are gossiping and spreading rumours aboutthem. Ideas of reference are a milder form in which referential thoughts are

entertained without conviction.

Among these rather disparate delusional beliefs there appears to be a

fundamental distinction to be made between delusions concerning commu-

nication and delusions concerning observation, and this distinction has now

been supported by two factor analyses of interview-based ratings of these

different beliefs (Bucci, Startup, Wynn, Heathcote, et al., 2008; Startup &

Startup, 2005). In both of these studies, delusions that others werecommunicating paralinguistically, nonverbally, through the public media

or via the arrangement of situations all loaded together on one factor, which

Startup and Startup (2005) called referential delusions of communication.

Delusions that others were observing surreptitiously or gossiping loaded on

a separate factor, called referential delusions of observation. The theoretical

DELUSIONS OF REFERENCE 111

account developed later in this paper is primarily concerned with delusions

of communication.

Delusions of reference are traditionally regarded as integral to persecu-

tory delusions (Leon, Bowden, & Faber, 1989). However, referential

delusions are also common in nonpersecutory patients with body dys-

morphic disorder (Phillips, McElroy, Keck, Pope, & Hudson, 1993), theysometimes occur in isolation from any other delusional beliefs, including

persecutory delusions (Startup & Startup, 2005), and they have been

reported in people without any diagnosable psychological disorder (Freeman

et al., 2005), even in children as young as 11 years old (Poulton et al., 2000).

Furthermore, in their analysis of ratings of different kinds of referential

delusion, Startup and Startup found that only referential delusions of

observation were associated with persecutory delusions (and auditory verbal

hallucinations); referential delusions of communication showed few sig-nificant associations with any other positive psychotic symptoms. Thus, it

appears that the traditional association between referential and persecutory

delusions applies primarily to referential delusions of observation.

PREVALENCE

Delusions of reference are one of the most common psychotic symptoms.

For example, they have been found in 67% of people with a diagnosis of

schizophrenia (World Health Organization, 1973), and in 64% of inpatients

suffering from a psychotic disorder (Minas et al., 1992). In the latter study

they were equal in frequency to persecutory delusions (64%), and more

common than auditory hallucinations (50%) or any other positive psychoticsymptom. Boydell et al. (2007) found that 50% of people with a recent first

episode of schizophrenia had delusions of reference. However, all these

studies employed a broad definition of delusions of reference. To date no

systematic study has been conducted into the prevalence of referential

delusions of communication specifically; the best information we have comes

from the studies by Startup and Startup (2005), Bucci, Startup, Wynn,

Heathcote, et al. (2008), and a recent unpublished study by the first author.

Among the combined patients from these studies who had acute psychoticdisorders, 69 out of 143 (48%) had referential delusions of communication.

Among the stabilised outpatient volunteers with schizophrenia in the study

by Startup and Startup, 10 out of 31 (32%) had these delusions.

AIMS OF THE PRESENT PAPER

Despite the prevalence of delusions of reference, very little research has been

focused on them. This is surprising since the single-symptom approach has

112 STARTUP, BUCCI, LANGDON

led to significant advances in the theoretical understanding of other

psychotic symptoms such as persecutory delusions (Freeman, 2007),

auditory hallucinations (David, 2004) and passivity experiences (Blakemore,

2003). Until recently, to the authors’ knowledge, only Frith (1992) had

developed an explicit theory about the cognitive processes involved

specifically in delusions of reference. In what follows, we first outline Frith’stheory and summarise its supporting evidence; we also identify what we

consider to be two important shortcomings of the theory. The rest of the

paper then focuses exclusively on referential delusions of communication.

First, we outline a new model designed to account for these delusions. Then

we review three relevant preexisting theories of psychotic states which,

although not developed specifically to account for referential delusions of

communication, appear nevertheless relevant to some aspects of our model.

We then posit a conceptual link between referential delusions of commu-nication and auditory verbal hallucinations in order to justify aspects of our

model. Along the way we present preliminary evidence in support of aspects

of our model.

FRITH’S ‘‘THEORY OF MIND’’ MODEL

According to Frith (1992), delusions of reference, together with persecutory

delusions and third-person auditory verbal hallucinations (i.e., voices

conversing), result from a disorder of Theory of Mind (ToM). ToM refers

traditionally to the capacity to represent and to infer the causal mental states

(e.g., the beliefs and intentions) of self and others in order to predict and

explain behaviour. Frith further suggested that ToM abilities developnormally in childhood in people with schizophrenia, unlike in autistic

spectrum disorders, but become impaired, to varying degrees, later in life

with the onset of the illness and during acute psychotic states. Thus, whereas

autistic people might be considered ‘‘mind-blind’’, people with schizophre-

nia with ToM impairment, in particular those with referential and

persecutory delusions, are better conceived of as ‘‘inaccurate mind-readers’’

(Langdon, 2005; see also Abu-Akel, 1999; Abu-Akel & Bailey, 2000;

Langdon & Brock, 2008, for related discussions); they inaccurately attributeintentions and beliefs to others.

The evidence is now unequivocal that people with schizophrenia show

ToM deficits that cannot be completely accounted for by impairments of

executive functioning, general cognitive impairments or general psycho-

pathology (Harrington, Siegert, & McClure, 2005). However, the evidence

supporting the theory that ToM deficits can explain persecutory and

referential delusions specifically might, at best, be considered inconsistent


(Abdel-Hamid et al., 2009; Harrington et al., 2005; Shryane et al., 2008;

Sprong, Schothorst, Vos, Hox, & van Engeland, 2007).

Despite the qualified empirical support for Frith’s theory, we believe his

model is limited with regard to the understanding of referential delusions

which it can offer. This is so for two main reasons. The first is that Frith’s

(1992) theory provides no account of one of the major defining features ofdelusions of reference, that is that they are self-referential. People with

delusions of reference may be poor at inferring the mental states of others

but, in order to explain the mistaken self-referential inferences they make,

more is required in the theory than deficits in the ability to use available

information to make appropriate inferences of the mental states of others.

The second concern is that Frith’s theory posits a common mechanism

underpinning referential and persecutory delusions, along with voices

conversing, and there are now reasons to think that any commonalitybetween referential and persecutory delusions, and voices conversing, applies

only to referential delusions of observation, not delusions of communication

(Startup & Startup, 2005; see earlier).

A NEW MODEL OF REFERENTIAL DELUSIONSOF COMMUNICATION

In what follows we focus exclusively on delusions of communication (for

brevity, we omit the term referential from now on). We present a new model

in Figure 1 to explain these delusions. This model is designed to account for

what appear to be four crucial aspects of the phenomenology of delusions of

communication: (1) that neutral stimuli are experienced as having personalsignificance; (2) that the neutral stimuli are experienced as communicating a

message nonverbally (or if the stimuli involve language, that the message is

communicated paralinguistically, that is, not by the surface meaning of the

words); (3) that the message concerns the self, that is, it is either addressed to

the self or is about the self; and (4) that the reality of the self-referent

communication is believed rather than being dismissed as implausible.

It will be apparent from our figure that we are adopting a two-factor (or

possibly multifactor) theory of the formation of delusions. In common withother two- (or more) factor theories (Coltheart, Langdon, & McKay, 2007;

Garety, Kuipers, Fowler, Freeman, & Bebbington, 2001; Langdon &

Coltheart, 2000), we attribute a crucial role to anomalous experiences

stemming from basic cognitive impairment(s). However, we also agree that

such cognitive disturbance is insufficient to explain the adoption of a

delusion. We share the view that a second factor, something beyond the first-

factor cognitive disturbance (which causes the anomalous experience), must

also be present to explain the delusional patient’s inability to reject the


implausible thought that is triggered by the anomalous experience (e.g., that

God is speaking to me when I hear voices).

The relevance here to our new theory of delusions of communication is

that, according to the two-factor approach, the nature of the (first-factor)cognitive disturbance explains the specific content of the delusion, whereas

the second factor accounts for its adoption and persistence (Langdon &

Coltheart, 2000). For example, the specific content of a passivity delusion is

explained by the loss of the sense of self-generation associated with initiating

one’s own movements, leading to an aberrant experience of ‘‘alien control’’

1. Neutral stimuli from the environmentinappropriately attract attention as of

being significant (salient).

2. Preconscious search for meaning ofperceived salience leads to over-activation of the nonverbal affect

lexicon.

3. Salience interpreted preconsciously asdetection of a (nonspecific) self-referent

nonverbal communicative signal.

4. Preconscious interpretative processesto decode message being signalled:

Activation of (a) decontextualisedmemories of previous nonverbalcommunications, and/or (b) self-

schemas

5. Aberrant conscious experience ofreceiving a content-specific

communication via nonverbal (orparalinguistic) channels

6. Belief-evaluationprocesses, e.g.,

capacity to reject animplausible thought

Impaired:Referential delusionof communication

adopted

Intact:Simple idea of reference,

quickly dismissed asimplausible

7. Autobiographicalmemory and self-schemas updated

Figure 1. A model of the formation of referential delusions of communication.


(Blakemore, 2003). In a similar vein, we postulate that the specific content of

a delusion of communication can be explained by identifying the particular

cognitive disturbance that gives rise to an abnormal referential experience of

communication.

In what follows, we overview the published research that appears to

provide some support for the various steps in our model, or at least to have abearing on them. Much of this research was not explicitly intended to

provide an account of delusions of reference but we believe, nevertheless,

that the relevance to our model is obvious. The amount of research that was

designed specifically to test aspects of this model is, admittedly, small. Thus,

we offer this model, rather boldly, with the desire to stimulate future research

as much as to summarise existing research.

STEP 1: NEUTRAL STIMULI INAPPROPRIATELY ATTRACTATTENTION AS SALIENT

Three notable preexisting theories have a possible bearing on this first step.

First, Hemsley (1987) argued that schizophrenia in general is characterisedby the ‘‘weakening of the influence of stored memories of regularities of

previous input on current perception’’ (p. 55). Furthermore, because of the

lack of influence of stored representations of past regularities of experience,

patients become aware of aspects of the environment that would not normally

reach awareness. This then triggers a search for meaning of the abnormal

experience of ‘‘significance’’ attached to some normally mundane event

(Hemsley, 1993). The relevance to our model is obvious. However, Hemsley’s

theory does not fully explain why personal significance is ascribed to thesemundane events which capture attention. Events can appear significant

without that significance necessarily entailing reference to the self.

In a somewhat similar vein, Corlett et al. (2006) have advanced a theory

which centres on inappropriate prediction error signalling. Prediction error

signalling refers to the signalling of a mismatch between an expected and an

actual input, which diverts attention to unexpected events and stimulates

associations between those events and other concurrent, but possibly

irrelevant, stimuli. Corlett et al. reasoned that inappropriate predictionerror signalling would lead to perceptual aberrations, especially sensations of

the environment being unusually bright, clear, or salient, and that these

sensations in turn would lead to ideas of reference. They tested this model

using functional magnetic resonance imaging of participants who were

administered ketamine prior to performing an associative learning task

designed to induce prediction errors. Among their most important findings

were that ketamine disrupts error-dependent learning activity in the right

frontal cortex and that participants who showed the most frontal activation


following a placebo developed the strongest perceptual aberrations and ideas

of reference following the administration of ketamine. Following adminis-

tration of a high dose of ketamine, levels of perceptual aberrations also

correlated highly (r�.7) with ideas of reference. However, in common with

Hemsley, these authors do not provide a clear explanation of why the ideas

that come to mind in reaction to the inappropriate prediction errorsignalling are self-referential.

Another account of psychosis which has some similarities to both of these

theories has been developed by Kapur (2003), who aimed to unite biological,

phenomenological, and pharmacological approaches to explain psychotic

symptoms in schizophrenia. He, like Gray, Feldon, Rawlins, Hemsley, and

Smith (1991), who mapped out the neurophysiological pathways involved in

Hemsley’s model, focused specifically on the role of dopamine, the synthesis

of which is known to be elevated among people who are experiencing apsychotic episode. Dopamine appears to be involved in detecting rewards in

the environment, enhancing understanding about rewards and their

associations, and identifying events as salient in order to stimulate and

maintain goal-directed behaviour (Kapur, Mizrahi, & Li, 2005). Thus,

Kapur proposed that dysregulated dopamine transmission results in

‘‘aberrant assignment of salience to external objects and internal representa-

tions’’ (p. 15) where information, which ought normally to be interpreted as

neutral, captures one’s attention. The search for the meaning of suchaberrant salience subsequently results in delusional beliefs.

Kapur, like Hemsley, did not explicitly intend to provide an account of

delusions of reference but his theory is readily applied to such delusions and,

furthermore, since dopamine is related to the experience of pleasurable and

aversive events for the self, his theory more readily accounts for the self-

referential nature of delusions of reference.

STEP 2: ACTIVATION OF THE NONVERBAL LEXICON

In conceiving of the specific types of cognitive disturbance which might give

rise to a referential experience of communication we offer a new conception

which takes as its starting point a conceptual link between delusions ofcommunication and auditory verbal hallucinations (the aberrant ‘‘referen-

tial’’ experience of hearing voices communicating to or about oneself).

Delusions of communication, we suggest, are similar to delusions concern-

ing voice-hearing in that both begin with an anomalous percept-like

experience of receiving a communication, a message. Startup and Startup

(2005) argued that it is the communicative nature of the referential

experiences of communication that naturally explains the self-referential


content of the delusion: that is, the message is experienced as being sent to

oneself. They also proposed that the main difference between auditory

verbal hallucinations and delusions of communication is that the commu-

nicative channel is spoken words in the former, while the latter centres on

nonverbal channels of communication (including paralinguistic vocal

content and nonvocal gestures and signs). For example, a stranger’sincidental movements might be experienced as a gesture that is intended

to communicate particular content to oneself (e.g., ‘‘I know you are a closet

homosexual’’).

As to why one patient should experience aberrant communicative content

via spoken verbal channels (i.e., the auditory verbal hallucinator) whereas

another patient experiences self-referential communication via nonverbal

channels (i.e., the patient with delusions of communication), there is

neuropsychological evidence to suggest specialised neural systems forprocessing these different types (verbal vs. nonverbal) of communicative

sign. For example, the right hemisphere (among right-handed people)

appears to be more specialised for processing a ‘‘vocabulary’’ of nonverbal

affective signals (e.g., facial expressions, prosody, and gestures), which has

been referred to as the nonverbal affect lexicon, and is conceived as relatively

modular (Bowers, Bauer, & Heilman, 1993). That is, the nonverbal lexicon

might be selectively disrupted (e.g., underconstrained by context or more

easily activated) in some individuals without any concurrent damage to thereception, production, and recall of linguistically decodable messages. Of

course, it is well known that the left hemisphere is (normally) specialised

for the latter type of processing. Thus, we are proposing that delusions

of communication are more likely to occur in those individuals whose

nonverbal affective lexicon is deregulated or easily activated.

STEP 3: DETECTION OF A NONVERBAL COMMUNICATION

To summarise the argument so far, we propose a new model of delusions

of communication, in which the specific content of these delusions can

be explained by postulating both a connection and a disconnection between

the abnormal percept-like referential experiences of communicationwhich seed these delusions and the abnormal false percepts which are

experienced by auditory verbal hallucinators. Both aberrant experiences

centre on the receiving of communications. What differs is the channel of

communication*nonverbal in the case of delusions of communication (for

which the right hemisphere is more specialised) and verbal in the case of

auditory verbal hallucinations (for which the left hemisphere is more

specialised).


Some preliminary empirical support for this aspect of our model comes

from a study by Bucci, Startup, Wynn, Heathcote, et al. (2008), which was

based on the signal detection study of auditory verbal hallucinations

conducted by Bentall and Slade (1985). Bentall and Slade showed that,

compared with controls, people with auditory hallucinations, and those

prone to hallucinations, were more biased to report hearing a voiceembedded in white noise when no voice was actually present (though they

were no less perceptually sensitive than the control participants). They

suggested that this bias occurred because the people with a disposition to

auditory verbal hallucinations misattributed self-generated communicative

content (i.e., the self-generated sense of receiving a message with varying

content) to an external source as the origin of that communicative content.

Thus, it was suggested that auditory verbal hallucinations reflect a ‘‘reality

discrimination error’’. We use the term ‘‘reality discrimination error’’ verygenerally here to refer to a mistaken attribution to an external source of

some content which is largely self-generated internally.

Bucci and colleagues adapted the Bentall and Slade paradigm to test the

theory that a cognitive disturbance, somewhat similar to that seen in

auditory verbal hallucinators, is also present in people with referential

delusions of communication. Since the people with delusions of commu-

nication purportedly ‘‘hallucinate’’ a nonverbal communicated message,

whereas the auditory hallucinators hear a verbal message, Bucci andcolleagues presented participants with video clips of an actor who, in

different clips, either used a widely recognised nonverbal gesture (e.g.,

beckoning) or else made an incidental movement of the same duration that

would not normally be construed as intending to communicate any meaning

to others (e.g., moving hair away from eyes). All of the clips were obscured

with visual noise (‘‘snow’’). The participants’ task following each clip was to

decide if a meaningful gesture or an incidental movement had been shown.

The results showed that people with versus without delusions of commu-nication had a more liberal bias towards reporting meaningful gestures as

being present. The main effect for presence versus absence of auditory verbal

hallucinations was nonsignificant.

Of course, these results show only that people with delusions of

communication were more willing to indicate that meaningful gestures had

been shown. However, one possible interpretation of the results, in line with

Bentall and Slade, is that the people with delusions of communication were

more biased to report gestures because they misperceived meaningfulgestures as being present in the absence of appropriate sensory information

that would justify the ‘‘gesture-perception’’ and that this occurred because

they misattributed meaningful communicative content, which was primarily

self-generated, to an external communicative source.


STEP 4: SEARCH TO DECODE THE MESSAGE

So, thus far, we have argued that neutral stimuli, which are inappropriately

assigned salience, activate the nonverbal lexicon in a preconscious search for

meaning. It is this activation which explains the detection of a nonverbal

communicative signal. However, while the study by Bucci, Startup, Wynn,

Heathcote, et al. (2008) suggested that people with delusions of commu-

nication are biased to misperceive neutral social events as having commu-nicative intent, it did not show that such people experience such apparent

communications as self-referential. Some suggestive evidence that this is so

has recently been presented by Bucci, Startup, Wynn, Baker, and Lewin

(2008) in their study of the interpretations that acutely psychotic people

place upon neutral social events.

In this study, video clips of gestures and incidental movements were

presented (without being obscured by visual noise), following each of

which participants selected one of four interpretations presented in randomorder: a ‘‘correct’’ interpretation if a gesture had been presented; another

gesture from the pool of gestures (incorrect); a rejecting or insulting

interpretation of the movement (always incorrect); and no gesture intended

(‘‘correct’’ interpretation if an incidental movement had been presented).

Although most of the interpretations selected by the patients were correct,

they misinterpreted significantly more of the nonmeaningful incidental

movements as gestures, compared with a control group, and selected

significantly more insulting interpretations of the clips even though all themovements in the clips were affectively neutral in content and the actor

maintained a neutral expression. What is most remarkable, however, was

that the differences between patients and controls were almost wholly due to

patients with delusions of communication; patients without delusions of

communication made hardly any more errors than the control participants.

One possible interpretation of the last of these findings is that the

misperceived communicative content (conveyed via nonverbal channels of

communication) often derives from the patient’s own self-critical beliefs (i.e.,their negative self-schemas) which then feed into the online processing of the

incoming gesture information in a top-down way.

In order to gain further insights concerning the origin of the meaningful

content that ‘‘fills in’’ the message conveyed by the nonverbal communicative

signal misperceived by people with delusions of communication, we now

consider one current theory of auditory verbal hallucinations that might be

relevant.

Waters, Badcock, Michie, and Maybery (2006) have suggested thatauditory verbal hallucinations derive from the unintentional activation of

auditory verbal memories, and other irrelevant current mental associations,

which are not recognised as originating as such because of deficits in


contextual or source memory. According to this theory, two cognitive

deficits combine to explain auditory verbal hallucinations1: deficient

inhibition of irrelevant memories and defective contextual binding. Support

for this theory comes first from a study which showed that people with

auditory verbal hallucinations had difficulty in suppressing memories of

prior events that were not relevant to the online reality (Badcock, Waters,Maybery, & Michie, 2005). More recently, Waters et al. found that almost

90% of people currently experiencing auditory verbal hallucinations had the

combination of deficits in both inhibition and context memory (compared

with only 33% of patients without such hallucinations), and that the people

with both kinds of deficit were about six times more likely to have auditory

hallucinations than the people without both deficits.

It seems possible that similar inhibitory and context-processing deficits

might also contribute to delusions of communication in that the intrusion ofirrelevant, poorly sourced memories, due to poor intentional inhibition,

might nuance the preconscious top-down ‘‘filling in’’ of the message

conveyed, in this case via nonverbal rather than spoken-verbal channels of

communication. Such memories will also likely contain the self-critical

information highlighted above when reviewing the Bucci, Startup, Wynn,

Baker, & Lewin (2008) findings concerning a negative bias in the

interpretation of gestures misperceived as meaningful.

To summarise this section, we propose that decontextualised memories ofhaving received nonverbal messages with particular content in the past, as

well as negative self-schemas, contribute to the ‘‘filling in’’ of the commu-

nicative signal with a typically negative, self-referential message.

STEPS 5 AND 6: BELIEF FORMATION

At the end of the processes outlined in the first four steps, the individual has a

conscious sense of having received a communication with specific content via

nonverbal (or paralinguistic) channels. The content of this communication

will be experienced quite naturally as self-referential since the content is that

of a message sent to the self from an external source, and the content might

also have been elaborated by preconscious intrusions from an insufficientlyinhibited and poorly sourced autobiographical memory. Aberrant referential

experiences of communication of this type might then lead only to simple

ideas of reference, which come to mind but which are quickly dismissed as

1 We note here that the Waters et al. model encompasses more than auditory hallucinations;

however, our focus here is on understanding the specific communicative content of referential

delusions of communication and so we refer specifically to the Waters et al. conception of auditory

verbal hallucinations.


implausible. If, however, the individual has further (second-factor) impair-

ment, which affects normal belief evaluation processes, then the implausible

referential idea may be accepted uncritically as true and a delusion of

communication will be adopted. This initial delusion may or may not

then lead on to other delusions and the elaboration of a related delusional

system. Current evidence suggests that there may be several contributorsto a delusion-prone cognitive style of this type, including: a jumping-to-

conclusions style of data gathering, belief inflexibility, tendencies to extreme

responding (Garety et al., 2005), an impaired capacity to inhibit a prepotent

tendency to upload and maintain experiential content into belief (Langdon,

Ward, & Coltheart, in press), and a bias against disconfirmatory evidence

(Woodward, Buchy, Moritz, & Liotti, 2007).

STEP 7: MEMORIES OF PREVIOUS SIMILARCOMMUNICATIONS

With regard to contents that individuals misperceive as having been

communicated via nonverbal channels, we would acknowledge that therichness of the message may vary considerably. One ‘‘receiver’’ may only

sense the presence of a communicative signal conveyed, for example, via a

gesture or an impersonal sign in the environment (e.g., a street sign) and

must then search for the meaning, whereas another receiver may experience

being directly ‘‘told’’ via the nonverbal sign that, for example, he/she is a

closet homosexual. This variation in the depth of content may reflect both

the varying involvement of preconscious processing of associations prior

to the initial conscious percept (see, e.g., Frith, 1979, in relation to explainingthe variable content of auditory verbal hallucinations) and the duration of

the referential delusional beliefs. With regard to the latter, Young (2008) has

proposed an interactionist model of delusions in which he suggests that, with

time, the delusional belief feeds back into the patient’s online preconscious

processing of incoming aberrant conscious experience. In relation to

delusions of communication, the idea here is that individuals move from

initially perceiving a relatively content-free nonverbal communicative signal

which they consciously interpret, at the time, as a message of disdain abouttheir hidden homosexual tendencies, to later experiencing the direct receipt

of a message of criticism about being a closet homosexual being conveyed

via a nonverbal communicative sign.

SUMMARY

Putting the foregoing together, we propose the following integration. At

the neurotransmitter level, dopamine dysregulation results in aberrant


assignment of salience to mundane environmental events (Kapur, 2003), or

abnormal glutamate firing in the prefrontal cortex causes inappropriate

prediction error signalling (Corlett et al., 2006; see also Hemsley’s, 1987,

suggestion of a failure of past regularities of experience to influence current

processing of sensory inputs). These accounts may not be in conflict with one

another but may be overlapping or complementary theories; Corlett et al.,2006). The aberrant signals of salience/significance which are triggered in

people with referential ideas or delusions of communication preferentially

activate right hemisphere networks which are dedicated to the processing of

nonverbal signals of communication (including paralinguistic vocal cues

and nonvocal gestures and signs). Memories and/or schemas, which are

‘‘primed’’, either because prior conscious processing to interpret the signals

has become automatic or because unconscious motivational factors are at

work, become activated in the preconscious interpretative processing of themeanings of the signals. The person fails to source the interpreted meaning

that comes to consciousness as being largely internally generated (perhaps

exacerbated by concurrent inhibitory deficits) and ‘‘misperceives’’ the receiv-

ing of a communication via nonverbal channels. The misperception is then

either dismissed as implausible or believed with conviction, depending on the

presence or absence of normal belief evaluation processes, which might be

disrupted in varying ways in delusion-prone individuals.

FUTURE RESEARCH

Much of the support for our model that we have put forward is suggestive or

speculative rather than confirmatory. Clearly more research is needed to testthe model thoroughly. Space does not permit us to describe all the research

we believe is needed but here we outline three areas. First, a central idea is

that delusions of communication are initiated when aberrantly salient events

differentially activate the nonverbal affect lexicon which resides in the right

hemisphere. This hypothesis might be testable with functional magnetic

resonance imaging if it should prove possible to reliably induce erroneous

perceptions of nonverbal communication in people with delusions of

communication, say using videos of incidental movements interspersedwith videos of genuine gestures. Second, we have suggested that delusions of

communication occur when memories of previous nonverbal communica-

tions are activated but are not recognised as such because of deficits in

context memory. Inhibitory impairments might also feature here via a failure

to suppress such memories. Adaptations of paradigms developed by

Badcock et al. (2005) to test source monitoring and inhibition deficits in

people with auditory verbal hallucinations might be useful to test these

ideas. Lastly, in order to explore the self-referential nature of delusions of


communication, one might investigate the influence of the patients’ own

previous experiences and self-critical thoughts on the misperceived commu-

nicative content, say using an adaptation of the Bucci, Startup, Wynn,

Baker, and Lewin (2008) methodology.

No doubt other researchers will consider different kinds of evidence to be

crucial to our model. If this paper stimulates them to put aspects of themodel to the test, then it will have served its purpose.

Manuscript received 7 May 2008

Revised manuscript received 4 March 2009

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delusions of reference: a new theoretical model

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