The perceptual and phenomenal capacity of mental imagery

Visual mental imagery of nonpredictive central social cues triggers automatic attentional orienting

Previous research has demonstrated that social cues (e.g., eye gaze, walking direction of biological motion) can automatically guide people's focus of attention, a well-known phenomenon called social attention. The current research shows that voluntarily generated social cues via visual mental imagery, without being physically presented, can produce robust attentional orienting similar to the classic social attentional orienting effect. Combining a visual imagery task with a dot-probe task, we found that imagining a non-predictive gaze cue could orient attention towards the gazed-at hemifield. Such attentional effect persisted even when the imagery gaze cue was counter-predictive of the target hemifield, and could be generalized to biological motion cue. Besides, this effect could not be simply attributed to low-level motion signal embedded in gaze cues. More importantly, an eye-tracking experiment carefully monitoring potential eye movements demonstrated the imagery-induced attentional orienting effect induced by social cues, but not by non-social cues (i.e., arrows), suggesting that such effect is specialized to visual imagery of social cues. These findings accentuate the demarcation between social and non-social attentional orienting, and may take a preliminary step in conceptualizing voluntary visual imagery as a form of internally directed attention.

A Systematic Review of Aphantasia: Concept, Measurement, Neural Basis, and Theory Development

People with aphantasia exhibit the inability to voluntarily generate or form mental imagery in their minds. Since the term "aphantasia" was proposed to describe this, it has gained increasing attention from psychiatrists, neuroscientists, and clinicians. Previous studies have mainly focused on the definition, prevalence, and measurement of aphantasia, its impacts on individuals' cognitive and emotional processing, and theoretical frameworks synthesizing existing findings, which have contributed greatly to our understanding of aphantasia. However, there are still some debates regarding the conclusions derived from existing research and the theories that were constructed from various sources of evidence. Building upon existing endeavors, this systematic review emphasizes that future research is much needed to refine the definition and diagnosis of aphantasia, strengthen empirical investigations at behavioral and neural levels, and, more importantly, develop or update theories. These multiple lines of efforts could lead to a deeper understanding of aphantasia and further guide researchers in future research directions.

How Social Media Algorithms Shape Offline Civic Participation: A Framework of Social-Psychological Processes

Even though social media platforms have created opportunities for more efficient and convenient civic participation, they are unlikely to bring about social change if the online actions do not propagate to offline civic participation. This article begins by reviewing the meta-analytic evidence on the relation between social media use and offline civic participation. Following this discussion, we present a theoretical framework that incorporates the attitudinal, motivational, and relational processes that may mediate the effect of social media use on offline civic participation. The framework highlights how social media algorithms may shape attitudes on important societal issues, promote generalized action goals among habitual users, and build social capital. We further discuss factors that may strengthen or undermine each of these processes, suggest ways to design and implement algorithms that may promote offline civic participation, and propose questions for future research.

The multisensory nature of human action imagery

Imagination can appeal to all our senses and may, therefore, manifest in very different qualities (e.g., visual, tactile, proprioceptive, or kinesthetic). One line of research addresses action imagery that refers to a process by which people imagine the execution of an action without actual body movements. In action imagery, visual and kinesthetic aspects of the imagined action are particularly important. However, other sensory modalities may also play a role. The purpose of the paper will be to address issues that include: (i) the creation of an action image, (ii) how the brain generates images of movements and actions, (iii) the richness and vividness of action images. We will further address possible causes that determine the sensory impression of an action image, like task specificity, instruction and experience. In the end, we will outline open questions and future directions.

The Neural Basis of a Cognitive Function That Suppresses the Generation of Mental Imagery: Evidence from a Functional Magnetic Resonance Imaging Study

This study elucidated the brain regions associated with the perception-driven suppression of mental imagery generation by comparing brain activation in a picture observation condition with that in a positive imagery generation condition. The assumption was that mental imagery generation would be suppressed in the former condition but not in the latter. The results show significant activation of the left posterior cingulate gyrus (PCgG) in the former condition compared to in the latter condition. This finding is generally consistent with a previous study showing that the left PCgG suppresses mental imagery generation. Furthermore, correlational analyses showed a significant correlation between the activation of the left PCgG and participants' subjective richness ratings, which are a measure of the clarity of a presented picture. Increased activity in the PCgG makes it more difficult to generate mental imagery. As visual perceptual processing and visual imagery generation are in competition, the suppression of mental imagery generation leads to enhanced visual perceptual processing. In other words, the greater the suppression of mental imagery, the clearer the presented pictures are perceived. The significant correlation found is consistent with this idea. The current results and previous studies suggest that the left PCgG plays a role in suppressing the generation of mental imagery.

Revisiting the blind mind: Still no evidence for sensory visual imagery in individuals with aphantasia

The inability to visualise was given the name aphantasia in 2015 by Zeman and colleagues. In 2018 we published research showing that fifteen individuals who self-identified as having aphantasia also demonstrated a lack of sensory visual imagery when undergoing the binocular rivalry imagery paradigm, suggesting more than just a metacognitive difference. Here we update these findings with over fifty participants with aphantasia and show that there is evidence for a lack of sensory imagery in aphantasia. How the binocular rivalry paradigm scores relate to the vividness of visual imagery questionnaire (VVIQ) and how aphantasia can be confirmed is discussed.

Working memory signals in early visual cortex are present in weak and strong imagers

It has been suggested that visual images are memorized across brief periods of time by vividly imagining them as if they were still there. In line with this, the contents of both working memory and visual imagery are known to be encoded already in early visual cortex. If these signals in early visual areas were indeed to reflect a combined imagery and memory code, one would predict them to be weaker for individuals with reduced visual imagery vividness. Here, we systematically investigated this question in two groups of participants. Strong and weak imagers were asked to remember images across brief delay periods. We were able to reliably reconstruct the memorized stimuli from early visual cortex during the delay. Importantly, in contrast to the prediction, the quality of reconstruction was equally accurate for both strong and weak imagers. The decodable information also closely reflected behavioral precision in both groups, suggesting it could contribute to behavioral performance, even in the extreme case of completely aphantasic individuals. Our data thus suggest that working memory signals in early visual cortex can be present even in the (near) absence of phenomenal imagery.

Modelling perception as a hierarchical competition differentiates imagined, veridical, and hallucinated percepts

Mental imagery is a process by which thoughts become experienced with sensory characteristics. Yet, it is not clear why mental images appear diminished compared to veridical images, nor how mental images are phenomenologically distinct from hallucinations, another type of non-veridical sensory experience. Current evidence suggests that imagination and veridical perception share neural resources. If so, we argue that considering how neural representations of externally generated stimuli (i.e. sensory input) and internally generated stimuli (i.e. thoughts) might interfere with one another can sufficiently differentiate between veridical, imaginary, and hallucinatory perception. We here use a simple computational model of a serially connected, hierarchical network with bidirectional information flow to emulate the primate visual system. We show that modelling even first approximations of neural competition can more coherently explain imagery phenomenology than non-competitive models. Our simulations predict that, without competing sensory input, imagined stimuli should ubiquitously dominate hierarchical representations. However, with competition, imagination should dominate high-level representations but largely fail to outcompete sensory inputs at lower processing levels. To interpret our findings, we assume that low-level stimulus information (e.g. in early visual cortices) contributes most to the sensory aspects of perceptual experience, while high-level stimulus information (e.g. towards temporal regions) contributes most to its abstract aspects. Our findings therefore suggest that ongoing bottom-up inputs during waking life may prevent imagination from overriding veridical sensory experience. In contrast, internally generated stimuli may be hallucinated when sensory input is dampened or eradicated. Our approach can explain individual differences in imagery, along with aspects of daydreaming, hallucinations, and non-visual mental imagery.

Implicit bias training can remove bias from subliminal stimuli, restoring choice divergence: A proof-of-concept study

Subliminal information can influence our conscious life. Subliminal stimuli can influence cognitive tasks, while endogenous subliminal neural information can sway decisions before volition. Are decisions inextricably biased towards subliminal information? Or can they diverge away from subliminal biases via training? We report that implicit bias training can remove biases from subliminal sensory primes. We first show that subliminal stimuli biased an imagery-content decision task. Participants (n = 17) had to choose one of two different patterns to subsequently imagine. Subliminal primes significantly biased decisions towards imagining the primed option. Then, we trained participants (n = 7) to choose the non-primed option, via post choice feedback. This training was successful despite participants being unaware of the purpose or structure of the reward schedule. This implicit bias training persisted up to one week later. Our proof-of-concept study indicates that decisions might not always have to be biased towards non-conscious information, but instead can diverge from subliminal primes through training.

Subjective signal strength distinguishes reality from imagination

Humans are voracious imaginers, with internal simulations supporting memory, planning and decision-making. Because the neural mechanisms supporting imagery overlap with those supporting perception, a foundational question is how reality and imagination are kept apart. One possibility is that the intention to imagine is used to identify and discount self-generated signals during imagery. Alternatively, because internally generated signals are generally weaker, sensory strength is used to index reality. Traditional psychology experiments struggle to investigate this issue as subjects can rapidly learn that real stimuli are in play. Here, we combined one-trial-per-participant psychophysics with computational modelling and neuroimaging to show that imagined and perceived signals are in fact intermixed, with judgments of reality being determined by whether this intermixed signal is strong enough to cross a reality threshold. A consequence of this account is that when virtual or imagined signals are strong enough, they become subjectively indistinguishable from reality.

Difficulty limits of visual mental imagery

While past work has focused on the representational format of mental imagery, and the similarities of its operation and neural substrate to online perception, surprisingly little has tested the boundaries of the level of detail that mental imagery can generate. To answer this question, we take inspiration from the visual short-term memory literature, a related field which has found that memory capacity is affected by the number of items, whether they are unique, and whether and how they move. We test these factors of set size, color heterogeneity, and transformation in mental imagery through both subjective (Exp 1; Exp 2) and objective (Exp 2) measures - difficulty ratings and a change detection task, respectively - to determine the capacity limits of our mental imagery, and find that limits on mental imagery are similar to those for visual short-term memory. In Experiment 1, participants rated the difficulty of imagining 1-4 colored items as subjectively more difficult when there were more items, when the items had unique colors instead of an identical color, and when they scaled or rotated instead of merely linearly translating. Experiment 2 isolated these subjective difficulty ratings of rotation for uniquely colored items, and added a rotation distance manipulation (10° to 110°), again finding higher subjective difficulty for more items, and for when those items rotated farther; the objective measure showed a decrease in performance for more items, but not for rotational degree. Congruities between the subjective and objective results suggest similar costs, but some incongruities suggest that subjective reports can be overly optimistic, likely because they are biased by an illusion of detail.

Read and Imagine: Visual Imagery Experience Evoked by First versus Second Language

This research examined visual imagery evoked during reading in relation to language. Following the previous reports that bilinguals experience less vivid imagery in their second language (L2) than first language (L1), we studied how visual imagery is affected by the language in use, characteristics of text, and readers' individual differences. In L1 and L2, 382 bilinguals read object texts describing pictorial properties of objects such as color and shape, spatial texts describing spatial properties such as spatial relations and locations, and excerpts from novels. They rated imagery vividness after each segment and the whole text, and rated the specific imagery characteristics (e.g., color, spatial relations). Regardless of the types of text or the timing of rating, the vividness of imagery was higher in L1 than in L2. However, English proficiency also predicted vividness in L2. Further, vividness in the object and spatial trials were predicted by the individual's object and spatial imagery skills. The effect of language on imagery depends on the text nature and difficulty, when and how vividness is measured, and individual differences.

Neural alterations in opioid-exposed infants revealed by edge-centric brain functional networks

Prenatal opioid exposure has been linked to adverse effects spanning multiple neurodevelopmental domains, including cognition, motor development, attention, and vision. However, the neural basis of these abnormalities is largely unknown. A total of 49 infants, including 21 opioid-exposed and 28 controls, were enrolled and underwent MRI (43 ± 6 days old) after birth, including resting state functional MRI. Edge-centric functional networks based on dynamic functional connections were constructed, and machine-learning methods were employed to identify neural features distinguishing opioid-exposed infants from unexposed controls. An accuracy of 73.6% (sensitivity 76.25% and specificity 69.33%) was achieved using 10 times 10-fold cross-validation, which substantially outperformed those obtained using conventional static functional connections (accuracy 56.9%). More importantly, we identified that prenatal opioid exposure preferentially affects inter- rather than intra-network dynamic functional connections, particularly with the visual, subcortical, and default mode networks. Consistent results at the brain regional and connection levels were also observed, where the brain regions and connections associated with visual and higher order cognitive functions played pivotal roles in distinguishing opioid-exposed infants from controls. Our findings support the clinical phenotype of infants exposed to opioids in utero and may potentially explain the higher rates of visual and emotional problems observed in this population. Finally, our findings suggested that edge-centric networks could better capture the neural differences between opioid-exposed infants and controls by abstracting the intrinsic co-fluctuation along edges, which may provide a promising tool for future studies focusing on investigating the effects of prenatal opioid exposure on neurodevelopment.

The pupillary light response as a physiological index of aphantasia, sensory and phenomenological imagery strength

The pupillary light response is an important automatic physiological response which optimizes light reaching the retina. Recent work has shown that the pupil also adjusts in response to illusory brightness and a range of cognitive functions, however, it remains unclear what exactly drives these endogenous changes. Here, we show that the imagery pupillary light response correlates with objective measures of sensory imagery strength. Further, the trial-by-trial phenomenological vividness of visual imagery is tracked by the imagery pupillary light response. We also demonstrated that a group of individuals without visual imagery (aphantasia) do not show any significant evidence of an imagery pupillary light response, however they do show perceptual pupil light responses and pupil dilation with larger cognitive load. Our results provide evidence that the pupillary light response indexes the sensory strength of visual imagery. This work also provides the first physiological validation of aphantasia.

Visual working memory in aphantasia: Retained accuracy and capacity with a different strategy

Visual working memory paradigms involve retaining and manipulating visual information in mind over a period of seconds. Evidence suggests that visual imagery (sensory recruitment) is a strategy used by many to retain visual information during such tasks, leading some researchers to propose that visual imagery and visual working memory may be one and the same. If visual imagery is essential to visual working memory task performance there should be large ramifications for a special population of individuals who do not experience visual imagery, aphantasia. Here we assessed visual working memory task performance in this population using a number of different lab and clinical working memory tasks. We found no differences in capacity limits for visual, general number or spatial working memory for aphantasic individuals compared to controls. Further, aphantasic individuals showed no significant differences in performance on visual components of clinical working memory tests as compared to verbal components. However, there were significant differences in the reported strategies used by aphantasic individuals across all memory tasks. Additionally, aphantasic individual's visual memory accuracy did not demonstrate a significant oblique orientation effect, which is proposed to occur due to sensory recruitment, further supporting their non-visual imagery strategy reports. Taken together these data demonstrate that aphantasic individuals are not impaired on visual working memory tasks, suggesting visual imagery and working memory are not one and the same, with imagery (and sensory recruitment) being just one of the tools that can be used to solve visual working memory tasks.

Mistaking imagination for reality: Congruent mental imagery leads to more liberal perceptual detection

Visual experiences can be triggered externally, by signals coming from the outside world during perception; or internally, by signals from memory during mental imagery. Imagery and perception activate similar neural codes in sensory areas, suggesting that they might sometimes be confused. In the current study, we investigated whether imagery influences perception by instructing participants to imagine gratings while externally detecting these same gratings at threshold. In a series of three experiments, we showed that imagery led to a more liberal criterion for reporting stimulus presence, and that this effect was both independent of expectation and stimulus-specific. Furthermore, participants with more vivid imagery were generally more likely to report the presence of external stimuli, independent of condition. The results can be explained as either a low-level sensory or a high-level decision-making effect. We discuss that the most likely explanation is that during imagery, internally generated sensory signals are sometimes confused for perception and suggest how the underlying mechanisms can be further characterized in future research. Our findings show that imagery and perception interact and emphasize that internally and externally generated signals are combined in complex ways to determine conscious perception.

Attention driven phantom vision: measuring the sensory strength of attentional templates and their relation to visual mental imagery and aphantasia

When we search for an object in an array or anticipate attending to a future object, we create an 'attentional template' of the object. The definitions of attentional templates and visual imagery share many similarities as well as many of the same neural characteristics. However, the phenomenology of these attentional templates and their neural similarities to visual imagery and perception are rarely, if ever discussed. Here, we investigate the relationship between these two forms of non-retinal phantom vision through the use of the binocular rivalry technique, which allows us to measure the sensory strength of attentional templates in the absence of concurrent perceptual stimuli. We find that attentional templates correlate with both feature-based attention and visual imagery. Attentional templates, like imagery, were significantly disrupted by the presence of irrelevant visual stimuli, while feature-based attention was not. We also found that a special population who lack the ability to visualize (aphantasia), showed evidence of feature-based attention when measured using the binocular rivalry paradigm, but not attentional templates. Taken together, these data suggest functional similarities between attentional templates and visual imagery, advancing the theory of visual imagery as a general simulation tool used across cognition. This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.

Cortical excitability controls the strength of mental imagery

Mental imagery provides an essential simulation tool for remembering the past and planning the future, with its strength affecting both cognition and mental health. Research suggests that neural activity spanning prefrontal, parietal, temporal, and visual areas supports the generation of mental images. Exactly how this network controls the strength of visual imagery remains unknown. Here, brain imaging and transcranial magnetic phosphene data show that lower resting activity and excitability levels in early visual cortex (V1-V3) predict stronger sensory imagery. Further, electrically decreasing visual cortex excitability using tDCS increases imagery strength, demonstrating a causative role of visual cortex excitability in controlling visual imagery. Together, these data suggest a neurophysiological mechanism of cortical excitability involved in controlling the strength of mental images.

Between-subject variability in the influence of mental imagery on conscious perception

Mental imagery and visual perception rely on similar neural mechanisms, but the function of this overlap remains unclear. One idea is that imagery can influence perception. Previous research has shown that imagining a stimulus prior to binocular presentation of rivalling stimuli increases the chance of perceiving the imagined stimulus. In this study we investigated how this effect interacts with bottom-up sensory input by comparing psychometric response curves for congruent and incongruent imagery in humans. A Bayesian hierarchical model was used, allowing us to simultaneously study group-level effects as well as effects for individual participants. We found strong effects of both imagery as well as its interaction with sensory evidence within individual participants. However, the direction of these effects were highly variable between individuals, leading to weak effects at the group level. This highlights the heterogeneity of conscious perception and emphasizes the need for individualized investigation of such complex cognitive processes.

Measuring Thought-Control Failure: Sensory Mechanisms and Individual Differences

The ability to control one’s thoughts is crucial for attention, focus, ideation, and mental well-being. Although there is a long history of research into thought control, the inherent subjectivity of thoughts has made objective examination, and thus mechanistic understanding, difficult. Here, we report a novel method to objectively investigate thought-control success and failure by measuring the sensory strength of visual thoughts using binocular rivalry, a perceptual illusion. Across five experiments ( N = 67), we found that thought-control failure may occur because of the involuntary and antithetical formation of nonreportable sensory representations during attempts at thought suppression but not during thought substitution. Notably, thought control was worse in individuals with high levels of anxiety and schizotypy but more successful in mindful individuals. Overall, our study offers insight into the underlying mechanisms of thought control and suggests that individual differences play an important role in the ability to control thoughts.

Redefining Visual Working Memory: A Cognitive-Strategy, Brain-Region Approach

The ability to remember and manipulate visual information is pervasive and is associated with many cognitive abilities. Yet despite the importance of visual working memory (VWM), there is little consensus among researchers in the field as to which neural areas are necessary and sufficient and which models best describe its capacity. Here, we propose that an assumption that all people remember visual information in the same way has led to much contention and inconsistencies in the field. By accepting that there are multiple cognitive strategies and methods to perform a VWM task, we introduce an individual “precision” approach to the study of memory. We propose that VWM should be redefined, not by the type of stimuli used (e.g., visual) but rather by the specific mental processes (e.g., visual imagery, semantic, propositional, spatial) and the corresponding brain regions used to complete the mnemonic task. We further provide a short how-to guide for measuring different mnemonic strategies used for working memory.

Visual mental imagery influences attentional guidance in a visual-search task

Visual mental imagery resembles visual working memory (VWM). Because both visual mental imagery and VWM involve the representation and manipulation of visual information, it was hypothesized that they would exert similar effects on visual attention. Several previous studies have demonstrated that working-memory representations guide attention toward a memory-matching task-irrelevant stimulus during visual-search tasks. Therefore, mental imagery may also guide attention toward imagery-matching stimuli. In the present study, five experiments were conducted to investigate the effects of visual mental imagery on visual attention during a visual-search task. Participants were instructed to visualize a color or an object clearly associated with a specific color, after which they were asked to detect a colored target in the visual-search task. Reaction times for target detection were shorter when the color of the target matched the imagined color, and when the color of the target was similar to that strongly associated with the imagined object, than when the color of the target did not match that of the mental representation. This effect was not observed when participants were not instructed to imagine a color. These results suggest that similar to VWM, visual mental imagery guides attention toward imagery-matching stimuli.

Mental imagery in psychiatry: conceptual & clinical implications

Mental imagery refers to the experience of perception in the absence of external sensory input. Deficits in the ability to generate mental imagery or to distinguish it from actual sensory perception are linked to neurocognitive conditions such as dementia and schizophrenia, respectively. However, the importance of mental imagery to psychiatry extends beyond neurocognitive impairment. Mental imagery has a stronger link to emotion than verbal-linguistic cognition, serving to maintain and amplify emotional states, with downstream impacts on motivation and behavior. As a result, anomalies in the occurrence of emotion-laden mental imagery has transdiagnostic significance for emotion, motivation, and behavioral dysfunction across mental disorders. This review aims to demonstrate the conceptual and clinical significance of mental imagery in psychiatry through examples of mood and anxiety disorders, self-harm and suicidality, and addiction. We contend that focusing on mental imagery assessment in research and clinical practice can increase our understanding of the cognitive basis of psychopathology in mental disorders, with the potential to drive the development of algorithms to aid treatment decision-making and inform transdiagnostic treatment innovation.

Are Fast Complex Movements Unimaginable? Pupillometric Studies of Motor Imagery in Expert Piano Playing

Motor imagery (MI; mental simulation of actions) shares certain mental representations and processes with executed movement (ME). This neurocognitive overlap between MI and ME may explain why the systematic use of MI improves skilled performance in numerous domains. Unfortunately, the attentional mechanisms underlying MI remain unresolved. Therefore, the present studies investigated the role of attentional effort (as measured by pupil dilation) in MI. We evaluated the effects of movement complexity and speed on expert pianists' pupil dilation as they physically executed and used MI to perform easy/complex and slow/fast music phrases. Results revealed that easy movements required similar levels of attentional effort during MI and ME. However, during complex movements performed at a fast speed, the correspondence between execution and imagery of movement was disrupted.

Exploring the functional nature of synaesthetic colour: Dissociations from colour perception and imagery

Individuals with grapheme-colour synaesthesia experience anomalous colours when reading achromatic text. These unusual experiences have been said to resemble 'normal' colour perception or colour imagery, but studying the nature of synaesthesia remains difficult. In the present study, we report novel evidence that synaesthetic colour impacts conscious vision in a way that is different from both colour perception and imagery. Presenting 'normal' colour prior to binocular rivalry induces a location-dependent suppressive bias reflecting local habituation. By contrast, a grapheme that evokes synaesthetic colour induces a facilitatory bias reflecting priming that is not constrained to the inducing grapheme's location. This priming does not occur in non-synaesthetes and does not result from response bias. It is sensitive to diversion of visual attention away from the grapheme, but resistant to sensory perturbation, reflecting a reliance on cognitive rather than sensory mechanisms. Whereas colour imagery in non-synaesthetes causes local priming that relies on the locus of imagined colour, imagery in synaesthetes caused global priming not dependent on the locus of imagery. These data suggest a unique psychophysical profile of high-level colour processing in synaesthetes. Our novel findings and method will be critical to testing theories of synaesthesia and visual awareness.

Association between Social Anxiety and Visual Mental Imagery of Neutral Scenes: The Moderating Role of Effortful Control

According to cognitive theories, verbal processing attenuates emotional processing, whereas visual imagery enhances emotional processing and contributes to the maintenance of social anxiety. Individuals with social anxiety report negative mental images in social situations. However, the general ability of visual mental imagery of neutral scenes in individuals with social anxiety is still unclear. The present study investigated the general ability of non-emotional mental imagery (vividness, preferences for imagery vs. verbal processing, and object or spatial imagery) and the moderating role of effortful control in attenuating social anxiety. The participants (N = 231) completed five questionnaires. The results showed that social anxiety was not necessarily associated with all aspects of mental imagery. As suggested by theories, social anxiety was not associated with a preference for verbal processing. However, social anxiety was positively correlated with the visual imagery scale, especially the object imagery scale, which concerns the ability to construct pictorial images of individual objects. Further, it was negatively correlated with the spatial imagery scale, which concerns the ability to process information about spatial relations between objects. Although object imagery and spatial imagery positively and negatively predicted the degree of social anxiety, respectively, these effects were attenuated when socially anxious individuals had high effortful control. Specifically, in individuals with high effortful control, both object and spatial imagery were not associated with social anxiety. Socially anxious individuals might prefer to construct pictorial images of individual objects in natural scenes through object imagery. However, even in individuals who exhibit these features of mental imagery, effortful control could inhibit the increase in social anxiety.

Enhanced mental imagery and intact perceptual organization in schizotypal personality disorder

According to a widely held view, psychotic disorders such as schizophrenia are characterized by a vague boundary between the perception of the external world and the inner imagery of persons, objects, and events. In this study, we addressed the perception-imagery debate in schizotypal personality disorder (SPD). Thirty individuals with SPD and 30 matched healthy subjects completed a lateral masking task. Participants were asked to detect a low-contrast Gabor patch flanked by two collinear Gabor masks. In the perceptual task, the masks were physically present, whereas in the imagery task, participants only imagined the masks. By applying a binocular rivalry paradigm, we also measured the imagery priming effect. Results revealed that, in the perceptual task, collinear masks similarly decreased contrast threshold in SPD and controls. In the imagery task, contrast threshold reduction (facilitation by the imagined masks) was more pronounced in SPD relative to the controls. In the binocular rivalry paradigm, individuals with SPD showed higher imagery priming effects as compared to healthy controls. Enhanced imagery was not related to schizotypal traits. These results indicate intact early visual perception and heightened imagery in SPD, which may be a trait marker of unusual experiences without psychotic disorganization.

The blind mind: No sensory visual imagery in aphantasia

For most people the use of visual imagery is pervasive in daily life, but for a small group of people the experience of visual imagery is entirely unknown. Research based on subjective phenomenology indicates that otherwise healthy people can completely lack the experience of visual imagery, a condition now referred to as aphantasia. As congenital aphantasia has thus far been based on subjective reports, it remains unclear whether individuals are really unable to imagine visually, or if they have very poor metacognition - they have images in their mind, but are blind to them. Here we measured sensory imagery in subjectively self-diagnosed aphantasics, using the binocular rivalry paradigm, as well as measuring their self-rated object and spatial imagery with multiple questionnaires (VVIQ, SUIS and OSIQ). Unlike, the general population, experimentally naive aphantasics showed almost no imagery-based rivalry priming. Aphantasic participants' self-rated visual object imagery was significantly below average, however their spatial imagery scores were above average. These data suggest that aphantasia is a condition involving a lack of sensory and phenomenal imagery, and not a lack of metacognition. The possible underlying neurological cause of aphantasia is discussed as well as future research directions.