Abstract
Since mental imagery cannot be observed from the outside, it is all the more important to make it measurable. Yet, many so-called mental imagery tasks confuse object and spatial imagery or can be solved entirely without mental imagery, making them inappropriate for the assessment of mental imagery strength. One promising measurement method is the binocular rivalry task by Pearson et al. (Current Biology 18(13):982–986, 2008), which uses mental imagery priming to quantify mental imagery strength. Here, we propose an improved equation for the binocular rivalry priming score to significantly increase its predictive validity. In a sample of 38 aphantasics and 73 controls, we demonstrate that the binocular rivalry priming score calculated by the new equation explains more variance in the self-reported mental imagery capacity than the original equation. The improved binocular rivalry priming score is particularly beneficial when only a few trials are recorded (e.g., due to time or attention constraints) or when people with low mental imagery (i.e., aphantasics) have to be identified. The improved binocular rivalry priming score is advantageous in many situations, making it the preferred measure for future research.
Overview/Introduction
Mental imagery is a fascinating aspect of human cognition, allowing us to visualize objects and scenes in our minds without any external visual input. However, measuring the strength of mental imagery has always been challenging because it cannot be directly observed. This research paper introduces an improved method for assessing mental imagery strength using a task known as the binocular rivalry task. This task has been refined to provide a more accurate measure of mental imagery, especially useful for identifying individuals with aphantasia—a condition where people cannot form mental images.
Methodology
The study involved two groups: 38 individuals with aphantasia and 73 control participants. Researchers used the binocular rivalry task, where participants view two different images, one for each eye, leading to a visual competition in the brain. The task measures how mental imagery can influence which image is perceived. The researchers proposed a new equation to calculate the binocular rivalry priming score, aiming to enhance its predictive validity. This score helps quantify the strength of mental imagery by analyzing how previous visual experiences influence current perception.
Key Findings
The improved binocular rivalry priming score explained more variance in participants' self-reported mental imagery capacity than the original score.
This new score is particularly beneficial when only a few trials are conducted, making it efficient for situations with time or attention constraints.
The improved score is more effective at identifying individuals with low mental imagery, such as those with aphantasia.
The study found a strong correlation between the improved priming score and self-reported vividness of visual imagery, indicating its reliability.
Implications
Research: The improved binocular rivalry priming score offers a more accurate tool for researchers studying mental imagery, potentially leading to better understanding and identification of aphantasia.
Clinical: Clinicians could use this method to assess and diagnose aphantasia more effectively, aiding in the development of tailored interventions or therapies.
Education: Educators might use insights from this research to better support students with varying levels of mental imagery ability, particularly those with aphantasia.
Limitations
The study acknowledges that behavioral measures validated with self-report measures can never surpass the accuracy of the self-reports themselves. This means that while the binocular rivalry task is useful, it may not capture all aspects of mental imagery.
The task might not identify individuals with unconscious mental imagery, as it primarily measures conscious visual experiences.
In summary, this research presents a significant advancement in measuring mental imagery, offering a more reliable and efficient method for both scientific and practical applications.