Project Title: The effect of visual field and transliminality score on common onset masking. Project Investigators: Steven J. Haase, Ph.D; Gary D. Fisk, Ph.D Project goals: The goal of the research is multifaceted, from looking at basic instrumentation and software performance of conducting perception experiments online (using PsyToolkit), to further investigating the joint influences of congruency and masking on simple shape identification. In addition, this exploratory study will investigate whether there are performance differences based on which visual field the display is presented to (left vs. right), and also whether there are individual differences based on one’s cognitive threshold (i.e., transliminality). Background: Common onset masking (COM) was first reported in a paper by DiLollo, Bischof, and Dixon (1993). This type of masking is similar to metacontrast, in that the masks and target do not overlap spatially. However, the difference is that common onset masking has its influence when there is more spatial separation between the target and mask—and in some cases the masking can occur with very sparse stimuli, such as four small dots. Our interest in this paradigm stems from prior exploratory work where we compared different forms of masking (pattern, metacontrast) along with temporal crowding. In addition, a congruency factor was included. There were two simple shapes (diamond, square) that could be masked or crowded with the same or different shapes. Congruency experiments are an important method for studying visual information processing (Schmidt, Haberkamp, & Schmidt, 2011). We obtained a small amount of foveal crowding in a condition that involved more spatial separation than typical metacontrast experiments. Investigating the influence of COM in a similar situation is a natural outgrowth of this research endeavor. Design: The experiment involves the following independent variables in a 2 x 2 within participants design: 1) Congruency (the target shape is the same as the masking shapes or different from the masking shapes). Two simple shapes are used—a horizontal and vertical rectangle 2) Visual field (displays are presented to the left or right of fixation (position above or below the fixation is also coded, so, subsequently, a separate analysis could be conducted on this position difference as well, collapsed across left/right—there is some evidence that visual shape information is better processed in the lower portion of the visual field—Zito et al. (2016)). Measures: We are collecting the following demographic information: Age, gender, handedness. We are collecting responses on the revised transliminality scale (Lange, Thalbourne, Houran, & Storm, 2000). We will measure response time for target identification and accuracy in target identification. Procedure: a. Initial pilot work (approximate n = 20). 1. Participants will click on a link to begin the study. 2. The first part will involve electronic informed consent. 3. Once participants provide informed consent, they will be asked to answer a number of demographic questions and then answer 17 questions that attempt to measure cognitive thresholds, via the “transliminality” scale (for information, see: https://www.researchgate.net/publication/12179666_The_Revised_Transliminality_Scale_Reliability_and_Validity_Data_From_a_Rasch_Top-Down_Purification_Procedure ). 4. Following completion of the survey, participants will complete a common onset masking perceptual task. The task will begin with instructions, 16 practice trials (with a longer target duration of 256 ms), then three sets of experimental trials (with 40 trials per set). The program manipulates the target shape (horizontal or vertical rectancle) on each trial and also the background shapes (horizontal or vertical rectangles that surround the target). The location of the target and background (masking) shapes is also varied from trial to trial in one of four positions around a fixation point. Following a 500 ms central fixation cross, Targets + Masks are displayed for 128 ms and trailing Masks for 500 ms. Participants have up to 3 s to make an identification response using the ‘c’ key for horizontal rectangle and ‘m’ key for vertical rectangle. There is a 1 s inter-trial interval. Feedback is provided on both practice and experimental trials. At the end, participants are asked to estimate their performance accuracy and then they are given information about the study (debriefing). The entire task takes approximately 15 minutes. 5. The link to the survey and experiment is here: https://www.psytoolkit.org/c/3.2.0/survey?s=Qa2Y2 b. Further studies will be based upon the results of the pilot work. There may need to be changes in stimulus timing, feedback, and/or other parameters, should the results be too variable or unclear to show reasonable effect sizes. If the results are closely in line with our predictions below, we will replicate the study with a separate sample of 20 participants. Hypotheses: 1. We predict a strong congruency effect with congruent trials being faster and more accurate than incongruent trials. Some of this effect may be due to response bias, in participants selecting the mask shapes for their response, since the target is difficult perceive. This may occur even though participants are informed that there will be an equal number of target and mask shapes and the shape for each is randomized across trials. The main effect of congruency is a highly expected (though not novel) finding. 2. We also predict that displays on the left of center will be faster and more accurate than displays on the right. While this effect may be somewhat small, it is based on the hypothesis that visual shape information is processed more quickly in the right compared to the left hemisphere (Verleger et al., 2010). This effect could also be due to the left-right reading bias in English. 3. In addition, there is research to support better processing for visual object information at the top of the display compared to the bottom part of the display (where motion perception shows an advantage). We can test for this as well, as half of the displays are presented below the fixation point. This hypothesis is more exploratory and subsidiary to #2 but there is some evidence to support it based on Zito et al. In fact, our displays combine movement in the process of COM. 4. Our investigation into transliminality is somewhat more exploratory, but there may be some connection with participants with higher scores on this scale having better perception of fleeting visual information. Sample size: Typically, we have found that a sample size of 20-25 is sufficient to explore hypothesis testing with adequate power. If effects are weak and or significant, the study will be reconceptualized. There are number of different options that can be modified such as the stimuli (we have done pilot work using letters), and the target duration (which is relatively long in this study (128 ms), compared to most COM studies (33-66ms), likely due to the movement in the display of target + masks in the near periphery to the trailing masks display appearing in the center.. References: Di Lollo, V., Bischof, W. F., & Dixon, P. (1993). Stimulus-onset asynchrony is not necessary for motion perception or metacontrast masking. Psychological Science, 4, 260–263. https://doi.org/10.1111/j.1467-9280.1993.tb00272.x Lange, R., Thalbourne, M. A., Houran, J., & Storm, L. (2000). The revised Transliminality Scale: Reliability and validity data from a Rasch top-down purification procedure. Consciousness and Cognition: An International Journal, 9(4), 591–617. https://doi.org/10.1006/ccog.2000.0472 Schmidt, F., Haberkamp, A., & Schmidt, T. (2011). Dos and don’ts in response priming research. Advances in Cognitive Psychology, 7(2), 120–131. https://doi.org/10.2478/v10053-008-0092-2 Verleger, R., Möller, F., Kuniecki, M., Śmigasiewicz, K., Groppa, S., & Siebner, H. R. (2010). The left visual-field advantage in rapid visual presentation is amplified rather than reduced by posterior-parietal rTMS. Experimental Brain Research, 203(2), 355–365. https://doi.org/10.1007/s00221-010-2237-z Zito, G. A., Cazzoli, D., Müri, R. M., Mosimann, U. P., & Nef, T. (2016). Behavioral differences in the upper and lower visual hemifields in shape and motion perception. Frontiers in Behavioral Neuroscience, 10. doi: 10.3389/fnbeh.2016.00128