Fantasy proneness, mental imagery and reality monitoring

Fantasy proneness, mental imagery and reality monitoring

Personality and Individual Differences 36 (2004) 1747–1754 www.elsevier.com/locate/paid Fantasy proneness, mental imagery and reality monitoring Andr...

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Personality and Individual Differences 36 (2004) 1747–1754 www.elsevier.com/locate/paid

Fantasy proneness, mental imagery and reality monitoring Andre Aleman *, Edward H.F. de Haan Psychological Laboratory, Helmholtz Institute, Utrecht University, The Netherlands Received 7 October 2002; received in revised form 9 May 2003; accepted 1 July 2003

Abstract Individual differences in fantasy proneness and vividness of mental imagery have been suggested to be related to source memory confusions. To test this hypothesis, two groups scoring either high or low on a measure of fantasy proneness (selected from a group of 231 subjects) were compared on measures of self report vividness of mental imagery, objective imagery ability and reality monitoring performance. The two groups differed significantly on ratings of imagery vividness (p < 0:01), but not on the imagery performance tasks, nor on reality monitoring performance. Our results indicate that, although fantasy proneness is associated with experiences of vivid mental imagery, it does not necessarily lead to reality monitoring errors. Ó 2003 Elsevier Ltd. All rights reserved. Keywords: Fantasy proneness; Reality monitoring; Mental imagery; Halluconations; Source memory

1. Introduction Fantasy proneness is a concept that denotes a range of experiences considered to be related to a deep involvement in fantasy (Wilson & Barber, 1983). Examples of such experiences are daydreaming, spending a large part of the time fantasising, experiencing strong bodily concomitants of fantasies and having fantasies with hallucinatory (‘‘real as real’’) intensities, amongst others (cf. Merckelbach, Horselenberg, & Muris, 2001). Fantasy proneness has been linked to phenomena such as paranormal and hallucinatory experiences. In addition, it has been hypothesised that fantasy proneness would be associated with hypnotizability and with false memories. It is important, however, to note that such associations have not always been confirmed (cf. Braffman & Kirsch, 1999). * Corresponding author. Address: Department of Psychiatry, Brain Division, University Medical Center, A01.126, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands. Tel.: +31-30-2508459; fax: +31-30-2505443. E-mail address: [email protected] (A. Aleman).

0191-8869/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.paid.2003.07.011

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Earlier studies have reported relations between dissociative experiences and source memory biases (specifically false positives, or ÔconfabulationsÕ) on the one hand, and between dissociative experiences and fantasy proneness on the other hand (Kuzendorf & Karpen, 1997; Merckelbach, Muris, Horselenberg, & Stougie, 2000). We hypothesised that fantasy proneness might be associated with mental imagery ability, and with biases in reality monitoring, i.e., the meta-cognitive process of distinguishing between internal and external sources of information. Mental imagery measures included subjective ratings of imagery vividness and more objective, behavioral measures of visual and auditory imagery performance. The hypothesis that fantasy proneness might lead to impoverished reality monitoring was derived from the theoretical framework provided by Johnson and Raye. According to Johnson and Raye (1981) and Johnson, Hashtroudi, and Lindsay (1993), reality discrimination difficulties can arise in one of two ways: (1) the images and percepts are less distinctive from each other with regard to their sensory characteristics (e.g., the images have an increased vividness, and will therefore resemble percepts more), (2) images and percepts are less distinctive from each other with regard to the meta-cognitive processes associated with each (e.g., generating mental images normally requires more cognitive effort than processing of percepts; this could be altered). It is conceivable that both processes might play a role in fantasy proneness, i.e. fantasy prone people might have more vivid imagery and it might also be more easy for them to generate imagery. Thus, both reality monitoring ÔpathwaysÕ might be predisposed towards confusing images and percepts more often. With regard to the fundamental premises of the Johnson and Raye (1981) model, findings have indeed been reported that are indicative of perception being generally more vivid (in terms of sensory details and contextual attributes) than imagery (Kosslyn, Sukel, & Bly, 1999). Moreover, it has been reported that increasing sensory similarity between perceived and imagined items increases source confusion (Kahan, 1996). Also consistent with the assumptions of the Johnson and Raye model is the finding that mental imagery may be related to reality monitoring, such that subjects with better imagery performance make more source confusions (Aleman & De Haan, 2001; Johnson, Raye, Wang, & Taylor, 1979). The present study was designed to investigate the relations between fantasy proneness, mental imagery and reality monitoring experimentally with subjects drawn from the normal population. We predicted that fantasy prone subjects would report more vivid imagery experiences, would perform better on imagery measures, but would make more source confusions on the reality monitoring task.

2. Method 2.1. Participants A high and a low scoring group of participants was selected from 231 undergraduate psychology students who completed a measure of fantasy proneness, the Creative Experiences Questionnaire (CEQ; Merckelbach et al., 2001). The CEQ is a dichotomous (yes/no) self-report scale consisting of 25 items. Examples of the items are ‘‘As a child, I had my own make believe friend or animal’’, and ‘‘I spend more than half of the day (daytime) fantasising or dreaming’’.

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Yes-answers are summed to obtain a total score (range 0–25), with higher scores indicating higher levels of fantasy proneness. The following criteria were used to define a high and a low fantasy prone group: participants with scores in the upper quartile were considered to be fantasy prone (CEQ scores >12) and participants in the lowest quartile were regarded to be low in fantasy proneness (CEQ scores <5). The N for both groups was 19 (3 male, 16 female) and 20 (3 male, 17 female), respectively. Age range was 18–24 years (mean 19.7, SD ¼ 1.5). As expected, the two groups differed significantly on CEQ ratings (p < 0:001), but not on age and level of education. 2.2. Materials and procedure Four dependent variables were included in the study. First, subjects were asked to complete a vividness of visual imagery questionnaire. In addition, they performed two behavioural imagery tasks: a visual form comparison imagery task, and a letter imagery task. Finally, a word list memory reality monitoring task was administered. Vividness of Visual Imagery Questionnaire: The Vividness of Visual Imagery Questionnaire (VVIQ; Marks, 1973) consists of 16 items in which subjects are asked to think of an object or scene and to rate the vividness of their image on a scale from 1 to 5; 1 represents an image that is ‘‘perfectly clear and as vivid as the actual experience’’ and 5 represents ‘‘no image present at all, you only know that you are thinking of the object’’. Subjects must rate the items twice, first with eyes open, and then with eyes closed. The questionnaire is scored by summing the ratings and dividing by two. Lower scores indicate more vivid imagery. Object form comparison imagery task: This task was modelled on the task described by Mehta, Newcombe, and De Haan (1992). Subjects had to indicate the odd-one-out in terms of visual form characteristics of a triad of common objects. The task consisted of 24 names of common objects that were presented in triads (three words, below each other) in the center of a computer screen. From each triad, the item that was most deviant in terms of visual form characteristics had to be indicated. An example of a triad would be: ‘‘pumpkin’’, ‘‘lettuce’’ and ‘‘tomato’’. This task requires subjects to form mental images in order to be able to make a correct judgement of the oddone-out (in the example given, ‘‘lettuce’’). Letter imagery task: Subjects had to indicate whether a cross-mark, presented in a 4 by 5 grid on a computer screen, would fall on an imaginary letter or not (this could be one of eight different letters, ÔcÕ, ÔfÕ, ÔhÕ, ÔjÕ, ÔlÕ, ÔpÕ, ÔsÕ, ÔuÕ.). A lowercase letter was presented before the grid, and subjects were asked to image the corresponding uppercase letter into the grid. This task was first described by Podgorny and Shepard (1978) and modified by Kosslyn, Cave, Provost, and Von Gierke (1988). We used a slightly modified variant of the task reported by Kosslyn et al. (1988). The letter is not actually presented in the grid, but must be imaged by the subject. For example, after a fixation point an undercase letter ÔfÕ is presented, followed by an empty grid with the X-mark at the lower right corner. The subject must decide whether the target would fall on an uppercase letter ÔFÕ or not. The task consisted of 32 trials, four trials for each of the letters (two‘‘on’’ and two ‘‘off’’ trials for each letter). Our modification of the task was that we allowed the X-mark to appear only in cells in which the chance that the X-mark would cover a letter was equal (thus, no X-marks appeared in the most left column, as most uppercase letters would cover these cells). The number of correct responses is included as a measure of imagery ability.

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Reality monitoring task: This task was a version of the category-association task used with schizophrenic patients by, e.g., Harvey (1985) and Morrison and Haddock (1997). During the learning-phase, one of the three most typical words (e.g., ÔGoldÕ) in one of 20 categories from Van Loon-Vervoorn and Pijpers-Kooiman (1988), was read aloud to the subjects. For a second word the category-name plus the first letter were presented (e.g. ÔMetal-I. . ..Õ) with the assignment to image the first word which came to mind, as if actually spoken. In the test-phase the participants had to indicate verbally for each of 30 words whether it was perceived earlier (ÔGoldÕ), imaged earlier (ÔIronÕ) or whether it concerned a new word (ÔCopperÕ). Thus, three types of words could be distinguished: (1) words read out loud by the experimenter (‘‘hear’’ words), (2) words generated by the subjects (‘‘think’’ words), and (3) new words. As a measure of source discrimination we computed the average conditional source identification measure (ACSIM; Murnane & Bayen, 1996), because compared with other empirical measures of source monitoring, it is the measure of source discrimination that is most independent of item recognition. In addition, we calculated the recognition parameter D (Batchelder & Riefer, 1990), as an index of sensitivity for words that were imaged. If there would be a specific bias for erroneously attributing internal information to an external source, this parameter should reveal a significant difference between the experimental and control group.

3. Results Mean ratings on the CEQ were 3 (SD ¼ 1.3) and 13.7 (0.8) for the low and high group, respectively. ANOVAs were conducted for the imagery variables and two reality monitoring parameters, ACSIM and D (discriminability of think words). Table 1 shows means and SDs for both groups on each measure. A significant difference between the two groups was observed on the VVIQ, F ð1; 37Þ ¼ 7:90, p < 0:01. The form comparison imagery task and the letter imagery task did not show different performance of the two groups. The fantasy prone group did not make more reality monitoring errors than the control group, F ð1; 37Þ ¼ 1:78, p > 0:10 for ACSIM. The groups neither differed on sensitivity for ÔthinkÕ words (D), p > 0:20.

Table 1 Means and SDs for the two groups classified as low and high on fantasy proneness on the measures of fantasy proneness, self-report imagery vividness, behavioural indices of imagery and reality monitoring Measure

Group

Mean

SD

Fantasy proneness (CEQ)

Low High Low High Low High Low High Low High

3 13.7 43.2 35.4 5.8 6.6 3.5 4.4 0.98 0.93

1.3 0.8 8.0 9.1 1.6 3.8 2.9 3.8 0.14 0.10

Self-report vividness of imagery (VVIQ) Object form comparison imagery Letter imagery Reality monitoring (ACSIM)

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4. Discussion The current study investigated whether fantasy proneness would be associated: (1) with increased mental imagery ability and (2) with impoverished reality monitoring performance. Three measures of mental imagery were included: a self-report measure of visual imagery vividness, and two behavioural measures of visual imagery. The measure of reality monitoring concerned source memory for experimenter-presented and self-generated words. The fantasy prone subjects differed from the control group on self-report imagery vividness, but on none of the other measures. The finding that fantasy prone subjects reported more vivid imagery can be interpreted in different ways. On the one hand, it can be seen as a validation of the concept of fantasy proneness, which has been predicted to be related to imagery vividness. This would add to the relations already established by Merckelbach et al. (2001) of the CEQ with absorption and dissociation, and support the validity of the measure. On the other hand, it is important to note that part of the relation between fantasy proneness and self-report imagery vividness may be due to same method variance, and the fact that the concepts might overlap to some extent. For example, five out of twenty five items of the CEQ target experiences that have to do with vividness of imagery (No. 11, 12, 16, 19 and 20). Merckelbach et al. (2001) denoted absorption and dissociation ‘‘close cousins’’ of fantasy proneness. Indeed, our evidence shows that self-report imagery vividness may also be considered a ‘‘close cousin’’ of fantasy proneness. In contrast to the results for the self-report imagery measure, fantasy prone people did not perform better on behavioural measures of mental imagery. This corroborates earlier reports of a dissociation between behavioural, performance-based measures of imagery and self-report questionnaires of the vividness of mental images (Aleman, B€ ocker, & De Haan, 1999; Aleman, Nieuwenstein, B€ ocker, & De Haan, 2000; Kosslyn, Brunn, Cave, & Wallach, 1984). The finding also suggests that fantasy proneness is a personality characteristic that is relatively independent of cognitive processing abilities. Indeed, our present results may call for a reconceptualisation of the reality monitoring framework outlined in Section 1. The possibility must be considered that it might not be vivid subjective experiences that matter, but rather personal significance or emotional content. Preliminary support for such notions come from studies showing specific reality monitoring and verbal self-monitoring biases for emotional material (Johns et al., 2001; Seal, Crowe, & Cheung, 1997). It has been suggested that fantasy proneness is a mediator in the relation between dissociation and false positive memory failures (Merckelbach et al., 2000). However, earlier studies have not found dissociation to be related to source memory accuracy (Kuzendorf & Karpen, 1997; Merckelbach et al., 2000; but see Van den Hout, Merckelbach, & Pool, 1996). In line with this, our current findings do not support an important contribution of fantasy proneness to poorer reality monitoring. Thus, contrary to our expectations, the current evidence shows that fantasy prone people are not at greater risk to confuse reality with imagination. It might be fruitful to continue the present line of research in psychiatric disorders associated with dissociation. Specifically, the precise role of imagery vividness and fantasy proneness in the symptoms observed in such populations deserves further investigation. In addition, hypotheses could be generated on the relation between fantasy proneness and the positive symptoms of schizophrenia, such as hallucinations and delusions. Although such symptoms have often been associated with poor ‘‘reality testing’’ (Mintz & Alpert, 1972; Aleman et al., in press) and reality

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monitoring (Brebion et al., 2000; Keefe, Arnold, Bayen, & Harvey, 1999), our finding that fantasy proneness is not related to reality monitoring accuracy may imply that other variables than fantasy proneness mediate such deficits associated with positive symptoms of schizophrenia (Aleman, B€ ocker, Hijman, Kahn, & De Haan, 2002). On the other hand, fantasy proneness has been associated with hallucination-like experiences (Merckelbach et al., 2001), and hallucinatory experiences have been shown to be closely related to daydreaming, a component of fantasy proneness (Aleman, Nieuwenstein, B€ ocker, & De Haan, 2001). Indeed, an earlier study with hallucination-prone subjects from the normal population did find reality monitoring biases specific for this group (Rankin, 1995; cf. Aleman et al., 2000). Studies that systematically compare hallucination-prone groups with and without psychiatric disorders on multiple measures of fantasy proneness, mental imagery and reality monitoring might shed more light on this question. It is important to bear in mind some limitations of the current study. Since the fantasy proneness measure mainly targets visual experiences, we included imagery measures in the visual modality. The inclusion of auditory imagery tasks would be instructive in future research, as the reality monitoring task was in the auditory modality. A potential limitation might be the homogeneous nature of our sample (university students) which may have introduced a range restriction in the reality monitoring error scores, thus attenuating possible differences between the groups. It remains to be seen whether these findings can be replicated in clinical groups, which tend to show larger variation in reality monitoring scores. On the other hand, it would be instructive to study subjects with very extreme fantasy proneness ratings, which may show reality monitoring difficulties that were not evident in the present student sample. Another limitation might be the use of only one reality monitoring task. More comprehensive assessments could be made if reality monitoring tasks would be included with, e.g., emotional material (cf. Seal et al., 1997) and visual stimuli (cf. Brebion et al., 2000). In addition, it may be worthwhile to investigate fantasy proneness in relationship to naturally occurring reality monitoring failures, such as reports of alien abductions experiences (Clancy, McNally, Schacter, Lenzenweger, & Pitman, 2002), realistic dreams (Rassin, Merckelbach, & Spaan, 2001) and hallucinatory experiences (Merckelbach & van de Ven, 2001). The relationship with measures of absorption and control of image generation also deserves further study. Finally, it has been suggested that memory confusions as measured with word lists might be different from those assessed with measures of autobiographical memory. For example, Wilkinson and Hyman (1998) observed that the tendency to change a source judgement for an autobiographical memory was not related to the number of errors in a word list task. They concluded that performance on word lists may not be a good predictor of an individualÕs performance in everyday memory tasks because the two may be based on different underlying processes. Future studies may therefore also include autobiographical measures for a more comprehensive assessment.

Acknowledgements We thank Gabri€el van der Blij, Inge de Jong, Elly Korendijk and Ilse Nieuwdorp for their assistance in data collection. We are also grateful to Professor Anthony David for his comments on a previous version of the manuscript. This work was supported by a grant from the Netherlands Organization for Scientific Research (NWO), grant MaG 575-25-007.

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