Aphantasia and involuntary imagery

Aphantasia is a condition that is often characterized as the impaired ability to create voluntary mental images. Aphantasia is assumed to selectively affect voluntary imagery mainly because even though aphantasics report being unable to visualize something at will, many report having visual dreams. We argue that this common characterization of aphantasia is incorrect. Studies on aphantasia are often not clear about whether they are assessing voluntary or involuntary imagery, but some studies show that several forms of involuntary imagery are also affected in aphantasia (including imagery in dreams). We also raise problems for two attempts to show that involuntary images are preserved in aphantasia. In addition, we report the results of a study about afterimages in aphantasia, which suggest that these tend to be less intense in aphantasics than in controls. Involuntary imagery is often treated as a unitary kind that is either present or absent in aphantasia. We suggest that this approach is mistaken and that we should look at different types of involuntary imagery case by case. Doing so reveals no evidence of preserved involuntary imagery in aphantasia. We suggest that a broader characterization of aphantasia, as a deficit in forming mental imagery, whether voluntary or not, is more appropriate. Characterizing aphantasia as a volitional deficit is likely to lead researchers to give incorrect explanations for aphantasia, and to look for the wrong mechanisms underlying it.

No verbal overshadowing in aphantasia: The role of visual imagery for the verbal overshadowing effect

The verbal overshadowing effect refers to the phenomenon that the verbal description of a past complex stimulus impairs its subsequent recognition. Theoretical explanations range from interference between different mental representations to the activation of different processing orientations or a provoked shift in the recognition criterion. In our study, 61 participants with aphantasia (= lack of mental imagery) and 70 controls participated in a verbal overshadowing paradigm. The verbal overshadowing effect did not occur in people with aphantasia, although the effect was replicated in controls. We speculate that this is either due to the lack of visual representations in people with aphantasia that verbal descriptions could interfere with, or to the absence of a shift in processing orientation during verbalisation. To rule out criterion-based explanations, further research is needed to distinguish between discriminability and response bias in people with aphantasia. Finally, data indicated that the verbal overshadowing effect may even be reversed in individuals with aphantasia, partly due to a lower memory performance in the no verbalisation condition. Effects of further variables are discussed, such as mental strategies, memory confidence, and difficulty, quantity and quality of verbalisation.

A matter of personality and point of view: How the interplay of reinforcement sensitivity and general attitudes towards pain impacts the responsivity to acute pain

BACKGROUND

The relatively stable individual differences reflected in Grey's revised reinforcement sensitivity theory (rRST), with foundations in neurophysiology and learning theory, appear particularly applicable to the study of pain. However, remarkably little research has been conducted in this area. In acute pain, activation of the behavioural approach system (BAS), the behavioural inhibition system (BIS) and the fight, flight, freezing system might depend on an individual's evaluation of pain. It was thus hypothesised that higher-order interactions of rRST traits and pain attitudes affect pain responsiveness.

METHODS

To investigate relationships between rRST traits and pain attitudes and to identify patterns between clusters of participants, we conducted a study in which N = 275 healthy participants filled in Reuter and Montag's rRST-Q and the General Attitudes Towards Pain Inventory (GATPI). Experimental (pressure, electrical, thermal) and self-report data of pain responsiveness were collected in a subsample (N = 113).

RESULTS

We found significant correlations between rRST-Q and GATPI subscales of up to r = 0.34. Two clusters were identified, significantly differing in rRST-Q and GATPI scores. Pain avoiders, characterized by high BIS, flight, freezing and negative pain attitudes, were found to be significantly more pain sensitive than pain approachers, characterized by high BAS, fight and positive pain attitudes. Moderate effects (d = 0.56 to d = 0.70) were demonstrated in subjective and objective measures and across pain modalities.

CONCLUSIONS

The present study expands the scientific knowledge on factors influencing pain responsiveness. Future research is needed to confirm implications for chronic pain prevention and therapy, particularly concerning pain avoiders.

SIGNIFICANCE

We have identified two clusters of participants, pain avoiders and pain approachers, that not only present differential patterns of revised reinforcement theory traits and general attitudes towards pain but also differ in their pain responsiveness. Pain avoiders appeared more pain sensitive compared to pain approachers, both in objective and subjective measurements, with implications for the improvement of chronic pain prevention and therapy.

Where's Wanda? The influence of visual imagery vividness on visual search speed measured by means of hidden object pictures

Previous research demonstrated effects of visual imagery on search speed in visual search paradigms. However, these effects were rather small, questioning their ecological validity. Thus, our present study aimed to generalize these effects to more naturalistic material (i.e., a paradigm that allows for top-down strategies in highly complex visual search displays that include overlapping stimuli while simultaneously avoiding possibly confounding search instructions). One hundred and four participants with aphantasia (= absence of voluntary mental imagery) and 104 gender and age-matched controls were asked to find hidden objects in several hidden object pictures with search times recorded. Results showed that people with aphantasia were significantly slower than controls, even when controlling for age and general processing speed. Thus, effects of visual imagery might be strong enough to influence the perception of our real-life surroundings, probably because of the involvement of visual imagery in several top-down strategies.

The role of dopamine in visual imagery-An experimental pharmacological study

Mental imagery enables people to simulate experiences in their minds without the presence of an external stimulus. The underlying biochemical mechanisms are poorly understood but there is vague evidence that dopamine may play a significant role. A better understanding at the biochemical level could help to unravel the mechanisms of mental imagery and related phenomena such as aphantasia (= lack of voluntary mental imagery), but also opens up possibilities for interventions to enhance or restore mental imagery. To test the hypothesis that acute dopamine depletion leads to a decrease in the strength of mental imagery, N = 22 male participants will be administered an amino acid mixture containing branched-chain amino acids (BCAAs) and tryptophan (TRP) to transiently reduce dopamine synthesis and further N = 22 male participants will receive a placebo. Plasma prolactin (PRL) levels are determined as a peripheral marker of brain dopamine function. The strength of mental imagery will be measured before and after ingestion of the BCAA/TRP mixture using the method of mental imagery priming. Additional exploratory analyses will use genetic data to investigate possible effects of variations on dopaminergic gene loci (e.g., DAT1) on dopamine levels and strength of mental imagery. The results show […].

Aphantasia within the framework of neurodivergence: Some preliminary data and the curse of the confidence gap

Aphantasia is a neurocognitive phenomenon affecting voluntary visual imagery, such that it is either entirely absent, or markedly impaired. Using both the social and medical models of disability, this article discusses the extent to which aphantasia can be understood as a disorder or just a form of neutral neurodivergence, given that imagery plays a central role in thinking and memory for most other people. Preliminary school performance data are presented, showing that low imagery does not necessarily complicate life, especially given compensatory strategies and low societal barriers. In addition, we discuss the consequences of labelling aphantasia a disorder with regard to self- and public stigma, and we provide further data regarding a confidence gap, by which aphantasics perceive themselves as performing worse than they objectively do. We conclude that aphantasia should be understood as neutral neurodivergence and that labelling it a disorder is not only wrong, but potentially harmful.

No increased prevalence of prosopagnosia in aphantasia: Visual recognition deficits are small and not restricted to faces

Aphantasia and prosopagnosia are both rare conditions with impairments in visual cognition. While prosopagnosia refers to a face recognition deficit, aphantasics exhibit a lack of mental imagery. Current object recognition theories propose an interplay of perception and mental representations, making an association between recognition performance and visual imagery plausible. While the literature assumes a link between aphantasia and prosopagnosia, other impairments in aphantasia have been shown to be rather global. Therefore, we assumed that aphantasics do not solely exhibit impairments in face recognition but rather in general visual recognition performance, probably moderated by stimulus complexity. To test this hypothesis, 65 aphantasics were compared to 55 controls in a face recognition task, the Cambridge Face Memory Test, and a corresponding object recognition task, the Cambridge Car Memory Test. In both tasks, aphantasics performed worse than controls, indicating mild recognition deficits without face-specificity. Additional correlations between imagery vividness and performance in both tasks were found, suggesting that visual imagery influences visual recognition not only in imagery extremes. Stimulus complexity produced the expected moderation effect but only for the whole imagery-spectrum and only with face stimuli. Overall, the results imply that aphantasia is linked to a general but mild deficit in visual recognition.

Imaginal extinction without imagery: Dissociating the effects of visual imagery and propositional thought by contrasting participants with aphantasia, simulated aphantasia, and controls

Imaginal exposure is a standard procedure of cognitive behavioral therapy for the treatment of anxiety and panic disorders. It is often used when in vivo exposure is not possible, too stressful for patients, or would be too expensive. Peter Lang's Bio-Informational Theory implies that imaginal exposure is effective because of the perceptual proximity of mental imagery to real events, whereas empirical findings suggest that propositional thought of fear stimuli (i.e., thinking about the stimuli without seeing them in the mind's eye) could be sufficient in therapeutical contexts. Exposure to propositional thought, instead of vivid mental imagery, would be more tolerable for patients since vivid imagery is associated with high emotional distress. To investigate whether mental imagery or propositional thought is crucial for the success of imaginal exposure, participants with the rare state of aphantasia (= absence of sensory mental imagery but with intact propositional thought) and two control groups were subjected to a fear conditioning paradigm followed by imaginal exposure and a reinstatement procedure. During imaginal exposure, control group 1 (N = 30) stared at a bright screen to disrupt visual imagery by incoming luminance (= simulated aphantasia), whereas control group 2 (N = 30) and participants with actual aphantasia (N = 30) kept their eyes closed. The results show […].

Measuring imagery strength in schizophrenia: no evidence of enhanced mental imagery priming

INTRODUCTION

Recent research shows ambivalent results regarding the relationship between mental imagery and schizophrenia. The role of voluntary visual imagery in schizophrenic hallucinations remains unclear. The aim of the study was to investigate the association between visual imagery, schizophrenia, and the occurrence of schizophrenic hallucinations using an objective visual imagery task.

METHODS

The sample consisted of 16 participants with schizophrenia (59.1% female; MAge  = 45.55) and 44 participants without schizophrenia (62.5% female; MAge  = 43.94). Visual imagery was measured using the Vividness of Visual Imagery Questionnaire (VVIQ) as well as the well-validated Binocular Rivalry Task (BRT). Occurrences of hallucinations were assessed using the Launay-Slade Hallucination Scale.

RESULTS

Participants with schizophrenia showed more hallucinatory experiences but did not score higher on either the VVIQ or the BRT than participants without schizophrenia. A correlation between the VVIQ and the BRT was found, validating the measurement of visual imagery and enabling the interpretation that visual imagery vividness is not enhanced in people with schizophrenia.

CONCLUSION

The association between mental imagery vividness and schizophrenia found in previous studies may be based on other facets of mental imagery than visual imagery.

Are catechol-O-methyltransferase gene polymorphisms genetic markers for pain sensitivity after all? - A review and meta-analysis

The catechol-O-methyltransferase (COMT) gene has arguably been the designated pain sensitivity gene for nearly two decades. However, the literature provides inconsistent evidence. We performed several meta-analyses including k = 31 samples and n = 4631 participants thereby revealing small effects of rs4680 on pain thresholds in fibromyalgia, headache and across chronic pain conditions. Moreover, rs4680 effects were found across pain patients when affected, but not unaffected, body sites were assessed. No effect was detected for any other SNP investigated. Importantly, our results corroborate earlier findings in that we found a small effect of COMT haplotypes on pain sensitivity. Our review and meta-analysis contribute to the understanding of COMT-dependent effects on pain perception, provide insights into research issues and offer future directions. The results support the theory that rs4680 might only impact behavioural measures of pain when descending pain modulatory pathways are sufficiently challenged. After all, COMT polymorphisms are genetic markers of pain sensitivity, albeit with some limitations which are discussed with respect to their implications for research and clinical significance.

No general pathological significance of aphantasia: An evaluation based on criteria for mental disorders

As awareness of the phenomenon of aphantasia (= lack of voluntary imagery) has increased in recent years, many psychotherapists ponder its clinical implications. The present study investigates whether aphantasia meets the criteria for mental disorders, i.e. statistical rarity, impairment in activities of daily living, violation of social norms and inappropriate behavior and personal distress. Prevalence of aphantasia was determined meta-analytically based on 3,543 participants. An international sample of 156 participants with aphantasia (58.3% male; M_age  = 35.23) and 131 controls (65.6% male; M_age  = 28.88) was assessed with the Reading the Mind in the Eyes Test, the Questionnaire for the Assessment of Everyday Memory Performance and the Aphantasia Distress Questionnaire, as well as measures of depression, anxiety and well-being. The prevalence of aphantasia was estimated at 3.5 to 4.8%. Participants with aphantasia scored significantly lower than controls on every day and autobiographical memory, but not on theory of mind. A subgroup of 34.7% of participants with aphantasia reported distress significantly associated with lower well-being and high levels of anxiety and depression. The level of distress increased with poorer performance in autobiographical memory and theory of mind. Although aphantasia meets the criterion of statistical rarity, the impact on activities of daily living and personal distress is too weak to justify a classification as a mental disorder. In a subgroup, however, distress can reach clinically relevant levels. In individual cases, it is therefore advisable to conduct a psychological assessment, for example by means of the Aphantasia Distress Questionnaire.

Pain sensitivity is associated with general attitudes towards pain: Development and validation of a new instrument for pain research and clinical application

BACKGROUND

With regard to attitudes towards pain, many questionnaires have been developed. Although undoubtedly useful, they were specifically designed for the use in chronic pain and are less suitable for the assessment in the general population. The purpose of the present paper was to develop a measure for the assessment of general attitudes towards pain applicable in the general population, regardless of clinical condition, and to test its psychometric properties.

METHODS

We developed the General Attitudes Towards Pain Inventory and conducted two studies in order to provide psychometric data: In a general population sample (N = 362, study one), participants were asked to complete a questionnaire battery. To assess test-retest reliability, participants were contacted again after four weeks (retest sample: N = 101). For the evaluation of criterion validity (study two), a sample with sadomasochistic sexual preference (N = 68) was additionally recruited.

RESULTS

Statistical analyses revealed, overall, acceptable internal consistencies and test-retest reliabilities. A ten-factor model showed acceptable fit and was superior to alternative models. The inventory demonstrated convergent and divergent validity. In this context, we found pain sensitivity to be associated with pain attitudes. Finally, compared to the general population sample, individuals with sadomasochistic sexual preference showed significantly higher scores on fascination-pleasure and challenge subscales.

CONCLUSIONS

In the present paper, we introduce a new and comprehensive instrument for pain research and provide evidence for its reliability and validity. In addition, we present new insights into how interindividual differences in pain sensitivity relate to pain attitudes.

Memory deficits in aphantasics are not restricted to autobiographical memory - Perspectives from the Dual Coding Approach

Scene Construction Theory suggests similar neural mechanisms for visual imagery and autobiographical memory, supporting the seeming scientific consensus that a loss of visual imagery affects autobiographical memory. Based on the Dual Coding Theory and the Reverse Hierarchy Model, we also assumed influences of visual imagery on recent visual memory and even verbal memory, although little evidence has been provided so far. Thus, in a sample of 67 congenital aphantasics (= persons without mental imagery) and 32 demographically matched controls, it was investigated whether deficits in visual imagery are associated with deficits in visual as well as verbal short-term and long-term memory. The memory tasks were theoretically selected based on task difficulty, retrieval condition, and subcategories of stimuli, as previous null findings were attributed to insensitive tasks that were solvable by aphantasics by means of non-visual alternative strategies. Significant group differences were found in all memory components, with aphantasics performing worse than non-aphantasics. Therefore, evidence was obtained for the influence of visual imagery on all memory components beyond autobiographical memory.

Imagine, and you will find - Lack of attentional guidance through visual imagery in aphantasics

Aphantasia is the condition of reduced or absent voluntary imagery. So far, behavioural differences between aphantasics and non-aphantasics have hardly been studied as the base rate of those affected is quite low. The aim of the study was to examine if attentional guidance in aphantasics is impaired by their lack of visual imagery. In two visual search tasks, an already established one by Moriya (Attention, Perception, & Psychophysics, 80(5), 1127-1142, 2018) and a newly developed one, we examined whether aphantasics are primed less by their visual imagery than non-aphantasics. The sample in Study 1 consisted of 531 and the sample in Study 2 consisted of 325 age-matched pairs of aphantasics and non-aphantasics. Moriya's Task was not capable of showing the expected effect, whereas the new developed task was. These results could mainly be attributed to different task characteristics. Therefore, a lack of attentional guidance through visual imagery in aphantasics can be assumed and interpreted as new evidence in the imagery debate, showing that mental images actually influence information processing and are not merely epiphenomena of propositional processing.