New paper in i-Perception

In the blink of an eye: Reading mental states from briefly presented eye regions. 

Schmidtmann, G., Logan, A. J., Carbon, C. C., Loong, J. T., Gold, I. (2020). In the blink of an eye: Reading mental states from briefly presented eye regions. i-Perception, 11(5), 1–18. [PDF]

Faces provide not only cues to an individual's identity, age, gender, and ethnicity but also insight into their mental states. The aim was to investigate the temporal aspects of processing of facial expressions of complex mental states for very short presentation times ranging from 12.5 to 100 ms in a four-alternative forced choice paradigm based on Reading the Mind in the Eyes test. Results show that participants are able to recognise very subtle differences between facial expressions ; performance is better than chance, even for the shortest presentation time. Importantly, we show for the first time that observers can recognise these expressions based on information contained in the eye region only. These results support the hypothesis that the eye region plays a particularly important role in social interactions and that the expressions in the eyes are a rich source of information about other peoples’ mental states. When asked to what extent the observers guessed during the task, they significantly underestimated their ability to make correct decisions, yet perform better than chance, even for very brief presentation times. These results are particularly relevant in the light of the current COVID-19 pandemic and the associated wearing of face coverings.

New preprint by our PhD student Hatem Barhoom

Barhoom, H.S., Joshi, M.R., Schmidtmann G. (2020) The effect of response biases on resolution thresholds of Sloan letters in central and paracentral vision, BioRxiv, https://doi.org/10.1101/2020.09.04.283119

My new book is published

Clinical Vision Science - A Concise Guide to Numbers, Laws, and Formulas

This book provides a concise and user-friendly guide to the most common and important numbers, laws and formulas in clinical vision science. Clinicians and trainees in ophthalmology, optometry, orthoptics, and ophthalmic dispensing, who are seeking an easy-to-use lab coat pocket size resource, will find this book to be an essential reference in clinical practice.

Clinical Vision Science: A Concise Guide to Numbers, Laws, and Formulas is clearly structured into basics, physical optics, visual optics and ophthalmic lenses, optical instruments, photometry, visual perception, clinical procedures, and anatomy & binocular vision. Each chapter contains a range of tables, formulas, large illustrations and flow charts to allow readers to quickly and accurately find key facts for each type of examination procedure.

https://www.springer.com/gp/book/9783030353391

Google Books Link

Vision science in times of self isolation

Vision Scientists! 

With ARVO and VSS cancelled and most of us working from home and under strict social distancing guidelines, we would like to invite vision scientists worldwide to join us for a weekly vision science virtual coffee break.

Come and join us on Zoom next Wednesday, 25th March.

Topic: Vision Science in times of social distancing

Time: Mar 25, 2020 03:00 pm London

08:00 am Pacfic

11:00 am Eastern

03:00 pm UK

04:00 Central European

Join Zoom Meeting

https://unibas.zoom.us/j/661371046

New paper in Perception

Schmidtmann, G., Jennings, B. J., Sandra, D. A., Pollock, J., & Gold, I. (2020). The McGill Face Database: Validation and Insights Into the Recognition of Facial Expressions of Complex Mental States. Perception. https://doi.org/10.1177/0301006620901671

Talk at the AVA Christmas Meeting, Cardiff University, 2019

Schmidtmann, G., Maria Zawadyl, “Summation within and between shapes in central and peripheral vision.“ Applied Vision Association (AVA) Christmas Meeting, Cardiff University, 2019 [SLIDES]

New paper in Vision Research

The processing of compound radial frequency patterns

Gunnar Schmidtmann, Frederick Kingdom, Gunter Loffler

Radial frequency (RF) patterns can be combined to construct complex shapes. Previous studies have suggested that such complex shapes may be encoded by multiple, narrowly-tuned RF shape channels. To test this hypothesis, thresholds were measured for detection and discrimination of various combinations of two RF components. Results show evidence of summation: sensitivity for the compounds was better than that for the components, with little effect of the components’ relative phase. If both RF components are processed separately at the point of detection, they would combine by probability summation (PS), resulting in only a small increase in sensitivity for the compound compared to the components. Summation exceeding the prediction of PS suggests a form of additive summation (AS) by a common mechanism. Data were compared to predictions of winner-take-all, where only the strongest component contributes to detection, a single channel AS model, and multi-channel PS and AS models. The multi-channel PS and AS models were modelled under both Fixed and Matched Attention Window scenarios, the former assuming a single internal noise source for both components and compounds or different internal noise sources for components and compounds respectively. The winner-take-all and single channel models could be rejected. Of the remaining models, the best performing one was an AS model with a Fixed Attention Window, consistent with detection being mediated by channels that are efficiently combined and limited by a single source of noise for both components and compounds.

Schmidtmann, G., Kingdom, F. A. A., & Loffler, G. (2019). The processing of compound radial frequency patterns. Vision Research, 161, 63–74. [PDF] [PubMed]

New paper in Vision Research

Cover: Jennings et al. (2019), Vision Research, 161, 12-17

Detection of distortions in images of natural scenes in mild traumatic brain injury patients.

Ben J. Jennings, Gunnar Schmidtmann, Fabien Wehbé, Frederick Kingdom, Reza Farivar

Mild traumatic brain injuries (mTBI) frequently lead to the impairment of visual functions including blurred and/or distorted vision, due to the disruption of visual cortical mechanisms. Previous mTBI studies have focused on specific aspects of visual processing, e.g., stereopsis, using artificial, low-level, stimuli (e.g., Gaussian patches and gratings). In the current study we investigated high-level visual processing by employing images of real world natural scenes as our stimuli. Both an mTBI group and control group composed of healthy observers were tasked with detecting sinusoidal distortions added to the natural scene stimuli as a function of the distorting sinusoid's spatial frequency. It was found that the mTBI group were equally as sensitive to high frequency distortions as the control group. However, sensitivity decreased more rapidly with decreasing distortion frequency in the mTBI group relative to the controls. These data reflect a deficit in the mTBI group to spatially integrate over larger regions of the scene.

Jennings, B. J., Schmidtmann, G., Wehbé, F., Kingdom, F. A. A., & Farivar, R. (2019), Detection of distortions in images of natural scenes in mild traumatic brain injury patients. Vision Research, 161, 12-17 [PDF] [PubMed]

VISTA Visiting Scholar

I have been awarded the  VISTA Distinguished Visiting Scholar Award and will stay for a research project at York University (Toronto) from  May 24th to June 14th.

Vision: Science to Applications (VISTA) is a collaborative research programme hosted by York University and funded by the Canada First Research Excellence Fund (CFREF, 2016-2023). My host Dr Ingo Fruend (https://www.yorku.ca/ifruend/) and I will be working on aspects of shape perception and the development of an optimisation algorithm for perimetry. I will also attend the Centre for Vision Research International Conference on Predictive Vision (http://www.cvr.yorku.ca/conference2019). 

More information on the VISTA research programme can be found below and here: http://vista.info.yorku.ca..