The enhanced processing account suggests that domain-specific expertise enhances the processing of information in that domain, such as enhanced color perception in visual artists and grapheme-color synaesthetes. A previous study (Ovalle-Fresa et al., 2021) found support for this account in both synaesthetes and non-synaesthete color experts; however, to fully understand the domain specificity of enhanced processing, other domains of expertise should be investigated and compared against each other in a double dissociation.

 

In this Stage 1 manuscript, Sachdeva et al. (2024) will investigate whether an enhanced processing account can explain domain-specific expertise in groups of color experts (i.e., visual artists) / grapheme-color synaesthetes and spatial experts (i.e., architects) / sequence-space synaesthetes. The spatial domain was chosen to compare to color since color and spatial processing recruit two distinctive cortical visual pathways: the ventral and dorsal streams, respectively. If enhanced processing is domain specific, then color experts / grapheme-color synaesthetes should show selective perceptual and memory performance enhancements for color tasks but not spatial tasks; and vice versa for spatial experts and sequence-space synaesthetes. The authors of this planned study further propose that perceptual performance should predict memory performance in the domain of expertise only; and that synaesthetes and non-synaesthetes with the same domain of expertise should perform similarly to each other.

 

To address these hypotheses, four independent groups will be recruited: grapheme-color synaesthetes, visual artists, sequence-space synaesthetes, and architects. Individuals with overlapping expertise and synaesthesia (e.g., visual artists who also have grapheme-color synaesthesia) will be excluded. Perception, short-term memory, and long-term memory for color (3 tasks) and space (3 tasks) will be assessed in all groups, and the authors will compare groups (synaesthetes, non-synaesthetes), domains of expertise (color, space), and task feature (color, space) in 2x2x2 linear mixed models. For all models, the authors predict that a significant interaction between domain of expertise and task feature will provide evidence for the domain specificity of the enhanced processing account. Additional analyses concerning working memory load (one, three, or five items) in the short-term memory tasks, and testing day (one, two, or three days post-training) in the long-term memory tasks, will be conducted to more deeply explore potential performance enhancements related to domain-specific expertise. Although these analyses may potentially provide additional evidence in favor of the hypothesized direction of effects, any deviation from predicted may pose a challenge for the interpretation of results. Nevertheless, this planned study is methodologically rigorous, and comprehensive in its aims.

 

The Stage 1 submission was evaluated by the recommender and two expert reviewers. Following revisions, the recommender judged that the manuscript met the Stage 1 criteria and awarded in-principle acceptance (IPA).

 

Level of bias control achieved: Level 6. No part of the data or evidence that will be used to answer the research question yet exists and no part will be generated until after IPA.
 
List of eligible PCI RR-friendly journals:
 

References
 

1. Ovalle-Fresa, R., Ankner, S., & Rothen, N. (2021). Enhanced perception and memory: Insights from synesthesia and expertise. Cortex, 140, 14-25. https://doi.org/10.1016/j.cortex.2021.01.024

2. Sachdeva, D. & Whelan, E., Ovalle-Fresa, R., Rey-Mermet, A., Ward, J., & Rothen, N.. (2024). How perceptual ability shapes memory: An investigation in healthy special populations. In principle acceptance of Version 2 by Peer Community in Registered Reports. https://osf.io/6wn4m

 

What is the relationship between perception and memory? Although these topics are typically investigated separately, there is evidence that these cognitive processes may be related: for example, individuals with synaesthesia may experience both enhancements in visual acuity and visual memory; and individuals with amnesia may also show deficits in visual perceptual processing. However, comprehensive evidence for the relationship between perception and different forms of memory (both short-term and long-term) is currently lacking.

 

In this Stage 1 manuscript, Whelan et al. (2024) seek to elucidate this relationship by investigating individual differences in perception and memory in a general population sample (i.e., in synaesthetes, non-synaesthetic relatives, and controls). There are two accounts that may explain enhanced perception and memory in synaesthesia: a ‘dual-coding’ account, which suggests that the extra perceptual information often experienced in synaesthesia (e.g., seeing colors for different letters of the alphabet) may contribute to encoding richer information in sensory memory; and an ‘enhanced processing’ account, which posits that enhanced perception and memory in synaesthesia may be due to genetic or environmental factors not directly related to synaesthetic experiences. In the former case, synaesthetes should perform more similarly to each other than to their non-synaesthetic relatives; in the latter case, non-synaesthetic relatives of synaesthetes should show similar perceptual and memory benefits. The current study should therefore find evidence in favor of one of these accounts over the other. In addition to this, the authors will generate multidimensional cognitive profiles of synaesthetes and their relatives, compared to non-synaethetes, including perception, memory, mental imagery and cognitive styles. 

 

The Stage 1 submission was evaluated by the recommender and two expert reviewers. Following revisions, the recommender judged that the manuscript met the Stage 1 criteria and awarded in-principle acceptance (IPA).

 
URL to the preregistered Stage 1 protocol: https://osf.io/6h8dx (under temporary private embargo)
 
Level of bias control achieved: Level 6. No part of the data or evidence that will be used to answer the research question yet exists and no part will be generated until after IPA.
 
List of eligible PCI RR-friendly journals:
 

 

References
 

1. Whelan, E., Sachdeva, C., Ovalle-Fresa, R., Rothen R., & Ward, J. (2024). Synaesthesia as a Model for Assessing Individual Differences in Visual Perception and Memory Performance. In principle acceptance of Version 3 by Peer Community in Registered Reports. https://osf.io/6h8dx

Are attention and consciousness inherently intertwined or distinct aspects of cognition? One report (Jiang et al. 2006) presented clear results in evidence of the latter. In this earlier study, the authors used a continuous flash suppression (CFS) paradigm which presents a colorful pattern to the dominant eye and stimuli of interest to the non-dominant eye; the colorful pattern masks the relevant stimulus from awareness. On each trial, the authors presented a sexually stimulating image and a scrambled image on different sides of a computer screen during CFS. They found that, even though participants were not consciously aware of the images, intact images that matched participants' sexual orientation could still capture attention.

 

Despite these seemingly clear results, the authors of the current Stage 1 manuscript pointed out that CFS studies are often not replicated, and the paper by Jiang et al. (2006) is no exception. Therefore, Chen et al. (2023) seek to replicate this study using a Bayesian (rather than NHST) analytic approach. This method will allow the authors to determine the strength of evidence for their hypotheses.

 

In this Stage 1 manuscript, Chen et al. present an introduction that motivates the replication, and a pilot study that replicated the procedure of Jiang et al. (2006) conducted with 21 participants. This led to a well-motivated statistical sampling plan and some small design changes for the main experiment, such as adding a staircasing procedure to remove potential performance ceiling effects, and using less extreme wording for stimulus attractiveness ratings. A clear study design template is presented, detailing the different hypotheses that will be tested, and what different outcomes would indicate.

 

The Stage 1 submission was evaluated by the recommender and two expert reviewers. Following revisions, the recommender judged that the manuscript met the Stage 1 criteria and awarded in-principle acceptance (IPA).

 

 

Level of bias control achieved: Level 6. No part of the data or evidence that will be used to answer the research question yet exists and no part will be generated until after IPA.
 
List of eligible PCI RR-friendly journals:

 

 

1. Jiang, Y., Costello, P., Fang, F., Huang, M., & He, S. (2006). A gender-and sexual orientation-dependent spatial attentional effect of invisible images. Proceedings of the National Academy of Sciences, 103, 17048-17052. https://doi.org/10.1073/pnas.0605678103

 

2. Chen, Y.-J., Scott, R.B., & Dienes, Z. (2023). Is conscious perception necessary to direct attention? A replication of Jiang et al. (2006). In principle acceptance of Version 2 by Peer Community in Registered Reports. https://osf.io/b2ncp