Content area
It has been reported in the literature that false memories or memory impairments can be found in individuals with high schizotypal personality traits. However, these studies based their findings exclusively on verbal information. Extending upon prior research, the present study examined whether the recall of recorded number of deaths (numerical information) can reflect a bias that is due to the schizotypal personality traits in a student sample. An online survey was conducted after the first COVID-19 lockdown in France. We assessed recall of deaths numbers, schizotypal personality traits, levels of paranoia, and trauma caused by COVID-19, as well as depression and anxiety scales. Analyses revealed a negative correlation between levels of schizotypal personality scores and the respondents' recall of deaths number announced by official sources, showing that the recall of an objective and numerical information can be also biased by schizotypal personality traits, as much as in episodic memory for verbal information. Expectedly, further analyses revealed that individuals high in schizotypal personality traits believed that real deaths numbers were superior to those announced by official governmental sources, suggesting that people with high schizotypal personality traits lowers the death number announced by official sources in their recall. Implications are discussed both in the field of memory bias studies for schizotypy and in the field of psychopathology for the lack of trust within people with high schizotypal personality and the involuntary nature of this bias.
It has been reported in the literature that false memories or memory impairments can be found in individuals with high schizotypal personality traits. However, these studies based their findings exclusively on verbal information. Extending upon prior research, the present study examined whether the recall of recorded number of deaths (numerical information) can reflect a bias that is due to the schizotypal personality traits in a student sample. An online survey was conducted after the first COVID-19 lockdown in France. We assessed recall of deaths numbers, schizotypal personality traits, levels of paranoia, and trauma caused by COVID-19, as well as depression and anxiety scales. Analyses revealed a negative correlation between levels of schizotypal personality scores and the respondents' recall of deaths number announced by official sources, showing that the recall of an objective and numerical information can be also biased by schizotypal personality traits, as much as in episodic memory for verbal information. Expectedly, further analyses revealed that individuals high in schizotypal personality traits believed that real deaths numbers were superior to those announced by official governmental sources, suggesting that people with high schizotypal personality traits lowers the death number announced by official sources in their recall. Implications are discussed both in the field of memory bias studies for schizotypy and in the field of psychopathology for the lack of trust within people with high schizotypal personality and the involuntary nature of this bias.
Public Significance Statement
This study suggests that the recall of a potentially traumatic event, such as a situation involving many deaths in society, can be altered in individuals with schizotypal personality traits within the general population. Our findings suggest that individuals with high schizotypal personality traits tend to recall and interpret very objective phenomena (e.g., the occurrence of deaths) differently, depending on the cognitive-perceptual and interpersonal dimensions of their personality.
Keywords: memory bias, schizotypal personality traits, mistrust, paranoid ideation, self-reported scales
The impact of the COVID-19 pandemic on mental health is now well-documented (Robinson et al., 2022; Salanti et al., 2022). Despite initial substantial concerns regarding mental health in adults from the general population, a recent meta-analysis showed that changes concerning mental health were of minimal to small magnitudes (Sun et al., 2023). However, distress induced by restrictions and lockdown measures might have had a greater impact on certain mental disorders highly vulnerable to stress, such as schizophrenia (Rudnick & Lundberg, 2012) or individuals with schizophrenia and schizotypal personality (Park et al., 2022). Nevertheless, the impact of this experience on the long-term memory system in schizophrenia spectrum pathology has yet to be explored.
Schizotypy belongs to a cluster of both genetically and environmentally influenced personality traits related to schizophrenia spectrum pathology (Cohen et al., 2015). There is a consensus in the literature that schizotypy personality and schizophrenia share overlapping neurocognitive and social functioning deficits. Specifically, meta-analyses indicate that individuals with schizotypal traits and patients with schizophrenia exhibit similar neurocognitive impairments (Cochrane et al., 2012; McClure et al., 2013), particularly in relation to episodic memory (Cadenhead et al., 1999; Sahakyan & Kwapił, 2016, 2018). These similar disruptions in cognitive and social functioning have led some researchers to propose that schizotypy exists on a continuum between nonpathological personality traits and schizophrenia spectrum disorders, with schizophrenia at the far end (Claridge & Beech, 1995).
According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (American Psychiatric Association, 2013), schizotypal personality is a "pervasive pattern of social and interpersonal deficits marked by acute discomfort with, and reduced capacity for, close relationships as well as by cognitive or perceptual distortions and eccentricities of behaviour, beginning by early adulthood" (p. 655). These deficits are associated with ideas of reference, social anxiety, odd/magical beliefs, unusual perceptions, odd/eccentric behaviour, no close friends, odd speech, constricted affect, and suspiciousness in a variety of situations.
From a multidimensional perspective, schizotypy has three dimensions (cognitive-perceptual, interpersonal, and disorganised; Vollema & van den Bosch, 1995). The cognitive-perceptual dimension is characterised by disturbances in thought content (ranging from bizarre beliefs to full blown delusions), unusual perceptual experiences (including illusions and hallucinations), and suspicion and paranoia. The interpersonal dimension involves diminished experiences, including lack of discourse, lack of energy, avoidance, anhedonia, and lack of affect (Kwapił & BarrantesVidal, 2015; Sahakyan & Kwapił, 2018). Finally, the disorganised dimension includes disruption of the ability to organise and express thoughts and behaviour, ranging from mild disruption of thinking and behaving to formalised disordered thinking and grossly disorganised acting (Kwapił & Barrantes-Vidal, 2015). Other dimensions have been proposed, including a distinct factor of paranoia (Horton et al., 2014), and impulsive noncompliance (Mason et al., 1995).
Moreover, there seems to be a consensus that schizotypal personality is a risk factor or vulnerability for schizophrenia (Meehl, 2001; Miller et al., 2002; Tyrka et al., 1995; Vollema et al., 2002). Furthermore, studies have cited schizotypy as a risk factor for posttraumatic stress disorder (Steel et al., 2005; Winfield & Kamboj, 2010). Some researchers have suggested that individuals with high schizotypy scores are particularly vulnerable to major changes in information-processing style, such as those that occur during a traumatic event (Steel et al., 2005). These changes can lead to severe consequences, including a memory bias toward traumatic experiences, significantly altering conscious information processing.
In summary, our current understanding is that schizotypal personality traits can serve as a model for vulnerability to schizophrenia and psychosis in the general population (Grant et al., 2018). According to a cross-sectional study with 256,445 participants from the general population across 52 countries, the prevalence rates for specific symptoms were: delusions of control: 4.8%, hallucinations: 5.8%, delusional mood: 7.1%, delusions of reference and persecution: 8.4% (Andrade & Wang, 2012). Thus, studying schizotypal personality traits can provide valuable data on vulnerability to psychosis.
In the present brief report, we were particularly interested in the memory bias in individuals with high and low schizotypal traits, in the context of daily announcements of mass deaths during the COVID lockdown.
Memory Bias in Schizotypal Personality
Regarding episodic memory impairments without the context of continuous stress, Sahakyan and Kwapił (2016, 2018) reported that people with schizotypal traits show deficits in free recall and recognition, particularly those with high negative schizotypal traits. Again, in another study, authors reported episodic memory impairments in people with schizotypal personality, but more for the recognition of emotion-induced versus neutral items (Hoshi et al., 2011; Kerns, 2005). In addition, Saunders et al. (2012) found increased false memories in individuals with high schizotypy scores.
Schizotypy is associated with differential patterns of episodic memory impairment, suggesting that different underlying mechanisms are at work. For example, a study assessing episodic memory in students with cognitive-perceptual dimension versus interpersonal dimension of schizotypy, using a combination of tasks (free recall, recognition, cued recall, and cued association), found that individuals with interpersonal dimension of schizotypy exhibited deficits on these tasks. This suggests that cognitive-perceptual and interpersonal dimension of schizotypy involve differential patterns of cognitive impairment (Sahakyan & Kwapił, 2016). Another study demonstrated that interpersonal dimension of schizotypy is associated with impaired retrieval: Participants with high cognitiveperceptual dimension of schizotypy scores were more likely to retrieve and give an answer, although they were not more accurate overall (Sahakyan & Kwapił, 2018). A study assessing episodic memory, specifically associative recognition, found difficulties in information processing (i.e., poorer accuracy and slower response times) in the interpersonal dimension of schizotypy (Sahakyan et al., 2019). Participants' episodic memory had differential forms of expression, depending on whether their schizotypy dimensions were cognitive-perceptual or interpersonal.
It has been suggested that people with interpersonal dimension of schizotypal personality avoid traumatic memories and retrieve fewer specific autobiographical memories of traumatic events. For instance, Harrison and Fowler (2004) found that interpersonal dimension of schizotypy were significantly associated with avoidance of traumatic events and a lack of specificity in autobiographical recall. Moreover, studies have cited schizotypy as a risk factor for posttraumatic stress disorder (Steel et al., 2005; Winfield & Kamboj, 2010). It has been suggested that individuals with high schizotypy scores are particularly vulnerable to major changes in information-processing style, such as those that occur during a traumatic event (Steel et al., 2005). This can have consequences for the encoding of memory traces.
However, all these studies presented above examined semantic or episodic memory, and thus involved only verbal information. In the present study, we were interested in numerical information gathered in a forced-choice questionnaire to see whether the estimation regarding death numbers can reflect traits from schizotypal personality.
Objectives
The goal of the present brief report was to explore whether the long-term memory systems of responders were biased in the context of repeated information about mass deaths in society during the first COVID-19 lockdown in France, revealing traits from schizotypal personality. We predicted that, because of the negative impact of daily death information, recall of the number of recorded deaths would be biased, especially in individuals with high schizotypal traits.
Our main hypothesis in this brief report is the following: We predicted that individuals' recall of numerical information, such as an officially announced death number, would differ significantly between higher versus lower schizotypal personality traits. More precisely, we predicted that individuals with higher schizotypal personality will remember lower official numbers because they believe that the real death numbers are far more important than given by the governmental sources. Our second hypothesis is that the raison in this memory bias is driven by the lack of trust or confidence in the official authorities, frequently observed in the schizotypal personality traits.
Methodology
Participants
Two hundred ten participants were recruited from university students through a mailing list of student groups. For all responses, participants were asked to consider the COVID-19 lockdown period when completing the questionnaires on LimeSurvey platform. The survey remained online between June 30, 2020 and July 15, 2020.
Inclusion and Exclusion Criteria
Inclusion criteria were (a) age 18 years or above, (b) French native speaker, and (c) living in France for the whole lockdown period (i.e., March 17,2020 to May 11,2020). Exclusion criteria were (a) failure to correctly answer the control questions in the questionnaire,1 (b) failure to complete all the questions concerning the recall of the numbers of deaths and other psychometric scales, and (c) taking more than 1 min to answer the questions about the numbers of deaths, to ensure that they truly recalled the number without searching for the answer on the internet. Thus, the final sample comprised 150 participants.
Consent
Confidentiality and privacy information was provided at the start of the questionnaire, as well as possible benefits and risks. The study was registered in https://clinicaltrials.gov under the identifier NCT04384419. It was approved by the Ethics Committee of Montpellier University Hospital and carried out in accordance with the Declaration of Helsinki.
Material and Procedure
Death Number Measures
Participants answered questions about information they were given during lockdown. As mentioned, to measure episodic memory, we used free recall (primary dependent variable). Participants were asked to answer questions about the numbers of deaths: recall of the mean number of deaths per fortnight on the national level and hours spent and type of media preferred for news related to pandemic situation in the following order:
* Hours spent to the news regarding the pandemic situation during lockdown; "How much time have you spent following COVID-19-related news per day, in hours?" (1 = less than 1 hr; 2 = between 1 and 2 hr; 3 = between 2 and 3 hr; 4 = between 3 and 4 hr; 5 = between 4 and 5 hr; 6 = between 5 and 6; 7 = more than 6 hr).
* Type of media preferred for the news related to pandemic situation; "Which of the following media have you preferred for the COVID-19-related news (multiple choice possible)?" (1 = television; 2 = radio; 3 = print newspapers; 4 = digital newspaper; 5 = governmental agencies; 6 = social media; 7 = other).
* Recall of officially announced numbers of deaths ( 1 min limitation); "Based on your recollection (even approximate), what was the official mean number of deaths reported for each fortnight [1st, 2nd, 3rd, 4th fortnight] of lockdown for the whole of metropolitan France?"
* Opinion regarding the real death numbers (Likert scale); "In your opinion was the total number of deaths due to COVID-19 that actually occurred during lockdown for the whole of metropolitan France lower or higher than the official figures?" (1 = extremely lower than what was announced; 2 = much lower than what was announced; 3 = slightly lower than what was announced; 4 = identical to the one announced; 5 = slightly higher that what was announced; 6 = much higher than what was announced; 7 = extremely higher than what was announced).
* Assessment of schizotypal personality traits; The SPQ (Dumas et al., 2000; Raine, 1991) is used to assess the nine characteristics of schizotypal personality described by the American Psychiatric Association (1994), offering both a dimensional and a categorical perspective. This self-report questionnaire comprises nine subscales exploring three dimensions of schizophrenic symptoms: interpersonal, cognitive/perceptual, and disorganised, and has good psychometric qualities (Raine, 1991). It has also been validated in French (Dumas et al., 2000; Ferchiou et al., 2017). We administered a shortened with 22 item French version (Ferchiou et al., 2017) of the French adaptation (Dumas et al., 2000) of the SPQ questionnaire (Raine & Benishay, 1995) with dichotomous responses.
* Assessment of anxiety and depressive symptoms; The Hospital Anxiety and Depression Scale (Zigmond & Snaith, 1983) is used to screen for anxiety and depressive disorders.
* Assessment of paranoid ideation; The Paranoia Scale (Fenigstein & Vanable, 1992) is a 20-item self-report questionnaire that addresses personal feelings, attitudes, traits, and behaviours characteristic of paranoia.
* Assessment of trauma caused by COVID-19; The COVID-Related Thoughts and Behavioral Symptoms questionnaire (Schneider et al., 2020) assesses COVIDrelated emotional distress and associated behaviours.
Results
Outliers
As our continuous data (recalled numbers of deaths) did not naturally follow a Gaussian distribution, we eliminated all data above the 95th percentile as outliers. This led to a sample size of 143 participants.
Sociodemographic Data
Participants provided sociodemographic data, including age, gender, education level, marital status, and employment status during the lockdown period. Descriptive characteristics of the sample are set out in Table 1 (categorical variables).
Statistical Analysis
As we had a non-Gaussian distribution for the recall of the numbers of deaths (Shapiro-Wilk test p < .001), we conducted nonparametric tests such as Spearman's rank correlation coefficient, priorly assuming in the model that all outcomes are uncorrelated (the Bonferroni correction). Regarding categorical answers for death numbers, as they were provided on Likert scales, we conducted nonparametric analysis of variance (ANOVAs), such as KruskalWallis for high versus low schizotypy comparisons. All statistical analyses were run with Jamovi software (2021) based on R (2020).
Correlations Between Psychometric Measures and Numbers of Deaths Recalled
We computed a correlation matrix between the mean numbers of deaths recalled and psychometric measures (see Table 2). According to the Spearman's p, there was a marginal significant coefficient (p < .055) for a negative correlation between schizotypal personality trait scores and the recalled death numbers from official sources. Again, we also observed a significant negative correlation between paranoia scale scores and the recalled death numbers (p < .03). As shown by significant positive correlations, anxiety, depression, as well as trauma caused by COVID seems to be concomitant with schizotypal personality traits and the paranoia scale scores in the context of pandemic related lockdown; however, they do not seem to be linked in any way to the mean number of recalled deaths. Further analysis has revealed that, it is particularly cognitive-perceptual dimension of schizotypal personality traits seems to be significantly correlated by the mean number of recalled deaths (Spearman's p: -0.189, p < .02).
Schizotypy Personality Traits
As there is no consensus in the literature as to how to identify individuals with high versus low schizotypy using the SPQ-B (22 points), we based the schizotypy subgroups on the mean score and standard deviation (N = 143; M = 10; a = 4.59). Thus, an SPQ-B score below 5 was deemed to indicate low schizotypy, and an SPQ-B score above 15 high schizotypy. This method appeared to be more appropriate relative to the most recent practices in the literature (Jacquet et al., 2020). The descriptive characteristics of low and high schizotypy profiles are set out in Table 3 (categorical variables).
A nonparametric analysis of variance known as Kruskal-Wallis analysis has revealed a significant difference between the low and high schizotypal individual's mean recall number of deaths (%2: 3.8, p < .05). According to the descriptive statistics, individuals with high schizotypal traits report having remembered from official sources 4,001 deaths during the lockdown while individuals with lower schizotypal traits report having recalled 6,861 deaths announced by official sources. Again, Spearman's p reveals a significant negative correlation between the recalled death numbers and schizotypal personality trait scores while comparing solely low and high schizotypal traits into the statistical model (p: -0.29, p < .02). The analyses have not revealed any significant outcome for exposure to the news (hours spent) between high and low schizotypal personality scale (p > .05), nor the type of media (p > .05).
Further analyses regarding the dimensions of schizotypal personality have revealed that there is a significant negative correlation only between cognitive-perceptual dimension of schizotypal personality and the recall of number of deaths from official sources (Spearman's p: -0.28, p < .02) and a strong tendency for negative correlation between interpersonal dimension of schizotypal personality and the recall of number of deaths (Spearman's p: 0.24, p < .059). Kruskal-Wallis analysis has confirmed that the recalled numbers of deaths differ significatively between high and low schizotypal personality traits for cognitive-perceptual (%2: 44.5, p < .001) and interpersonal dimensions (/2: 43, p < .001).
Regarding the opinions about the real death numbers in contrast from official sources, we conducted another analysis between participants with high versus low schizotypy traits on answers to the following question: "In your opinion, was the total number of deaths due to COVID-19 that actually occurred during lockdown for the whole of metropolitan France lower or higher than the official figures?" The Kruskal-Wallis analysis revealed a significant difference between participants with high versus low schizotypal traits (%2 = 4.3, p < .039). Participants with low schizotypal traits reported that the number of deaths was lower than the official figure (4.37 on Likert scale), whereas those with high schizotypal traits reported that the number of deaths (5.11) was higher than the official figure.
Discussion
Our primary aim in this study was to assess the quantitative expression of memory in the context of an extraordinary and unique event, namely the mass deaths caused by COVID-19, combined with limitations on social interaction due to lockdown. To this end, and based on recent findings regarding trauma, anxiety, and depressive symptoms, we predicted that psychological traits, particularly schizotypal personality traits, would be reflected in the recall of death numbers (i.e., numerical recall). We administered an online survey in which participants had to answer questions regarding the numbers of deaths that occurred during lockdown, followed by several psychometric tests (anxiety and depressive symptoms, paranoid ideation, schizotypal personality traits, and trauma caused by COVID-19). Participants did not know beforehand that they would be responding to questions regarding the numbers of deaths.
There is currently a tremendous debate in the literature regarding the properties of events and the psychological processes that allow such events to be retrieved in memory. For instance, according to dual-process theory, retrieval is based either on the recollection of contextual cues or on familiarity (feeling of knowing) judgments (see Yonelinas, 2002). Some authors, such as Nosofsky (2011), have suggested that the difference between recollection and familiarity is not qualitative, but instead stems from the strength of the memory traces and the similarities/differences between exemplars. This framework is compatible with Hintzman's (2001) view of purely episodic human memory, as well as with Oker and Versace's (2010, 2014) critics of structural memory approach. Thus, authors continue to debate whether the distinctions between remembering, knowing, and even guessing are based on a quantitative process (Nairne, 2006) or on qualitatively distinct processes (see Gardiner et al., 2002).
In the light of these theories, it is worth mentioning that whereas the recollection of emotionally meaningful items has been thoroughly studied in the literature, the expression of episodic memory for numerical information has received far less attention. The same is true, for the literature on people with schizotypal personality traits. Hence, our primary goal here was to study recall of the numbers of deaths that occurred during the COVID-19 lockdown, as this information was extensively and repeatedly broadcast, meaning the distinctions between familiarity, guessing and recollection might become blurred in a forced-choice situation (see Brunel et al., 2010; Gardiner et al., 2002). In other words, the context of mass deaths in society ironically provided us with an experimental situation in which people's responses to the question "How many died?" would be determined not only by their memory performance but also potentially by a bias reflecting their psychological state.
It is also worth acknowledging that memory for repeated events involves a specific process compared to a deliberate encoding. In this matter, there is already an established literature indicating that when a person experiences similar events, the recall is somewhat difficult to be accurate. Historically, the most well-known theoretical framework for repeated-event memory is the fuzzy trace theory (Brainerd & Reyna, 1990, 2004; Reyna et al., 2016), and the script theory (Schank & Abelson, 1977; for a review, see Dilevski et al., 2021). While each theory has its particularities, the common point of this framework is to propose that in the case of a repeated event, there are two distinct encoding processes: one for details and the source information of an event, whereas the other one is for a general level (what usually happens). The fluctuations in the repeated events are the cause of the inaccurate retrieval. On the other hand, a distinctive instance increases the memorability of an instance (MacLean et al., 2018). Extending upon prior research, authors have reported that in the case of repeated events, participants were less likely to report correct details than those who had experienced an isolated event (Deck & Paterson, 2021; Theunissen et al., 2017). Moreover, it has also been suggested that the effect of emotional stress on memory for repeated events should be studied as a distinct phenomenon (Dilevski et al., 2020; Theunissen et al., 2017). Indeed, according to Theunissen et al. (2017), adults who have witnessed several similar traumatic events are less accurate in their testimony than adults who have witnessed a single traumatic event. Thus, a legitimate question arises regarding the range of accuracy of traumatic event recall: Can this range be interpreted as a bias? Can this bias reflect personality traits?
According to our statistical analysis, there is a negative correlation between the scores of schizotypal personality and the recalled number of deaths in our sample. Indeed, when we compared participants with higher schizotypal personality scores reported a lower estimation of death numbers due to the pandemic in contrast to those with low schizotypal personality scores. This seems particularly the case for individuals scoring further in the cognitive-perceptual dimension of schizotypal personality traits and to a lesser extent in the interpersonal dimension. Cognitive-perceptual dimension is characterised by disturbances in thought content, unusual perceptual experiences, and suspicion and paranoia (Vollema & van den Bosch, 1995) while interpersonal dimension involves diminished experiences, including lack of discourse, lack of energy, avoidance, anhedonia, and lack of affect (Kwapił & Barrantes-Vidal, 2015; Sahakyan & Kwapił, 2018).
To interpret these results, we analysed responses to the question "In your opinion, was the total number of deaths due to COVID-19 that actually occurred during lockdown for the whole of metropolitan France lower or higher than the official figures?" Analysis showed that participants with high schizotypal traits responded that deaths were higher than official figures, reflecting a difference of opinion with the official reports. Although there is no direct evidence in our study, we believe that this difference can be explained by mistrust and suspiciousness to official sources, both symptomatic of schizotypal personality (Wong & Raine, 2018). As reported by Kwapił et al., 2012, cognitive-perceptual dimension of schizotypal personality is associated with increased suspiciousness. Taken together, our findings reflect the inability of individuals with high schizotypal personality traits to recall the same objective information as individuals with lower schizotypal personality traits.
Our results can also be interpreted in the light of information processing and its relationship to maladaptive self-processing. Previous research indicates that individuals with high cognitiveperceptual dimension of schizotypal personality traits are more susceptible to trauma-related intrusive memories following a stressful event (Holmes & Steel, 2004; Marzillier & Steel, 2007; Steel et al., 2008; cited by Jones & Steel, 2012). Steel et al. (2005) argued that high-scoring individuals with schizotypy exhibit a lower level of contextual integration, which is automatic, compared to those with low scores. This difference in processing style can explain inability to conduct contextual integration during or after a traumatic event.
Based on this understanding, it is reasonable to acknowledge that a new traumatic event, such as the deaths caused by COVID-19, will have a stronger impact on the autobiographical memory of individuals with high schizotypal personality traits compared to those with low traits. This interpretation suggests that the effect observed in our study results from an automatic and involuntary processing of autobiographical memory in individuals with high schizotypal personality traits.
Limitations of the Study
Although we interpreted the fact that individuals with high schizotypal personality traits believes that the real death numbers were higher than what officially reported by mistrust and suspiciousness, one might find it interesting that the paranoid ideation was not correlated with the recall of number of deaths in people with high schizotypal personality sample. However, when taking account all the participants, there is indeed a negative correlation between paranoia scale and the recalled deaths numbers. Other than the reduction in the sample of high schizotypal personality sample (N = 28), we believe the use of our "Paranoia Scale" (Fenigstein & Vanable, 1992) represents a limitation of our study. The use of "the revised Green et al. Paranoid Thoughts Scale" (R-GPTS) would be a more appropriate tool than Paranoid Scale (Fenigstein & Vanable, 1992) for schizotypal personality studies. Paranoid Scale (Fenigstein & Vanable, 1992) has one general factor assessing paranoid ideation, whereas R-GPTS (Freeman et al., 2021) has a two-factor solution assessing persecution and ideas of reference separately. Assessing ideas of reference (tendency to view innocuous stimuli as having a specific meaning for the self) and persecution separately would be better suited for our study. As a matter of fact, after viewing the results of our study, ideas of reference seem to be a better candidate to evaluate in our study, as referential thinking is known to alter maladaptive self-processing and personality, particularly with individuals with schizotypal personality traits (Cicero & Kerns, 2011). Moreover, it should be acknowledged our study lacks some control measures such as conspiracy measures or social desirability of participants. Given the fact that this is an online questionnaire, there is no way to unsure that some individuals responded alone.
Another limitation of our study would be the generalisation of our finding from a student sample to the general population and to the individuals clinically diagnosed with schizotypal personality disorder. However, the validation study of the SPQ-22 questionnaire that we used in our study (Raine & Benishay, 1995) addresses this issue. The authors included more than 490 university students in their study, and a subsample was invited back for clinical interviews based on the Diagnostic and Statistical Manual of Mental Disorders, third edition, revised (American Psychiatric Association, 1987). They reported that the SPQ scale and its dimensions exhibited significant correlations with the clinical interviews according to Diagnostic and Statistical Manual of Mental Disorders, third edition, revised criteria (p < .005). These correlations ranged from .34 to .73, with an average correlation of 0.62. The authors of the SPQ-22 questionnaire state that their scale demonstrates a strong correlation with the DSM-Ш criteria for schizotypal personality disorder.
It is well-established in the literature that schizotypy as a personality disorder according to DSM-V (American Psychiatric Association, 2013) and nonclinical individuals with schizotypal traits in the general population (Claridge & Beech, 1995; Nelson et al., 2013) are two distinct constructs that exhibit significant overlap. The dimensional model proposed by Claridge and Beech (1995) suggests that schizotypal personality traits, or the predisposition to psychosis, are distributed along a continuum within the general population. This continuum ranges from low schizotypy and good psychological health to extremely high schizotypy and potential dysfunction in the form of psychosis (Grant et al., 2018; Nelson et al., 2013). This dimensional approach implies that there is a boundary between health and illness, indicating that high levels of schizotypy may be associated with schizophrenia but do not necessarily indicate dysfunction (Nelson et al., 2013). Evidence from genetic, neuropsychological, environmental, and biological research supports the notion that psychologically healthy individuals fall along a continuum (Nelson et al., 2013). Additionally, brain-level correlates suggest a continuum of abnormalities between schizotypy and schizophrenia (Shepherd et al., 2012). These considerations highlight the complexity and overlap between schizotypy as a personality trait and schizotypal personality disorder. It is important to acknowledge that our study focuses on schizotypal personality traits in the general population and does not directly assess clinical diagnosis or dysfunction.
Conclusions
We can draw three main conclusions from this study. First, in our study, free recall or estimation for numerical information shows elements of memory bias from schizotypal personality traits. Further studies should use analysis such as receiver operating characteristics with this dependent variable to establish sensibility and decision thresholds for memory bias in schizotypal personality traits. Second, a situation of mass deaths in society gives the opportunity to study the impact in the psychological space to such an extent that individuals with high schizotypal personality traits' estimation of real events becomes altered. Third, individuals with high schizotypal personality traits (4%, according to Rosell et al., 2014) seem to interpret very objective phenomena (e.g., occurrence of deaths) differently, depending on the cognitive-perceptual and interpersonal dimension of their personality traits in an automatic and involuntary way.
Résumé
La littérature publiée antérieurement rapporte que les faux souvenirs ou les problèmes de mémoire peuvent se retrouver chez les personnes ayant de forts traits de personnalité schizotypique. Cependant, les conclusions de ces études se fondaient exclusivement sur de l'information obtenue verbalement. Pour donner suite aux recherches antérieures, la présente étude visait à évaluer si la remémoration du nombres de décès comptabilisés (information numérique) peut rendre compte d'un biais causé par des traits de personnalité schizotypique chez un échantillon d'étudiants. Une enquête en ligne a été menée après le premier confinement dÛ à la COVID-19 en France. Cette enquête visait à évaluer la remémoration des nombres de décès, les traits de personnalité schizotypique, les niveaux de paranoïa et les traumatismes provoqués par la COVID-19, et comportait des échelles de la dépression et de l'anxiété. Les analyses ont mis au jour une corrélation négative entre les scores de personnalité schizotypique et la remémoration par les répondants des nombres de décès rapportés par des sources officielles, ce qui démontre que la remémoration d'une information objective et numérique peut être biaisée par les traits de personnalité schizotypique, comme c'est le cas avec la mémoire épisodique de l'information verbale. Comme on s'y attendait, des analyses plus poussées ont démontré que les personnes présentant de forts traits de personnalité schizotypique croyaient que les nombres réels de décès étaient supérieurs à ceux annoncés par des sources gouvernementales officielles, ce qui donne à penser qu'elles diminuent, dans leur remémoration, le nombre de décès annoncés par les sources officielles. Les incidences de ces conclusions sont abordées à la fois dans le cadre des études sur les biais de la mémoire, en ce qui a trait à la schizotypie, et dans le domaine de la psychopathologie, en ce qui a trait au manque de confiance qui caractérise les personnalités très schizotypiques ainsi qu'à la nature involontaire de ce biais.
Mots-clés : biais de la mémoire, traits de personnalités schizotypique, méfiance, idéation paranoïde, échelles d'autoévaluation
1 Items were added to detect random completion or careless responders (e.g., "Please do not fill the blank for this question and click Next" [attention check] or "Please do not reply to the question below"), and simulation of psychotic symptoms (Moritz et al., 2013; e.g., "I was abducted by aliens").
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Received February 2, 2023
Revision received September 14, 2023
Accepted September 19, 2023 *
Copyright Canadian Psychological Association Jan 2025