Person:
Serrano Pedraza, Ignacio

First Name

Ignacio

Last Name

Serrano Pedraza

URI

https://hdl.handle.net/20.500.14352/80226

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Psicología

Department

Psicología Experimental, Procesos Cognitivos y Logopedia

Area

Psicología Básica

Identifiers

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Search Results

Now showing 1 - 10 of 13

Contrast thresholds reveal different visual masking functions in humans and praying mantises
(Biology Open, 2018) Tarawneh, Ghaith; Nityananda, Vivek; Rosner, Ronny; Errington, Steven; Herbert, William; Busby, Natalie; Tampin, Jimmy; Read, Jenny; Arranz Paraíso, Sandra; Serrano Pedraza, Ignacio
Recently, we showed a novel property of the Hassenstein–Reichardt detector, namely that insect motion detection can be masked by ‘undetectable’ noise, i.e. visual noise presented at spatial frequencies at which coherently moving gratings do not elicit a response (Tarawneh et al., 2017). That study compared the responses of human and insect motion detectors using different ways of quantifying masking (contrast threshold in humans and masking tuning function in insects). In addition, some adjustments in experimental procedure, such as presenting the stimulus at a short viewing distance, were necessary to elicit a response in insects. These differences offer alternative explanations for the observed difference between human and insect responses to visual motion noise. Here, we report the results of new masking experiments in which we test whether differences in experimental paradigm and stimulus presentation between humans and insects can account for the undetectable noise effect reported earlier. We obtained contrast thresholds at two signal and two noise frequencies in both humans and praying mantises (Sphodromantis lineola), and compared contrast threshold differences when noise has the same versus different spatial frequency as the signal. Furthermore, we investigated whether differences in viewing geometry had any qualitative impact on the results. Consistent with our earlier finding, differences in contrast threshold show that visual noise masks much more effectively when presented at signal spatial frequency in humans (compared to a lower or higher spatial frequency), while in insects, noise is roughly equivalently effective when presented at either the signal spatial frequency or lower (compared to a higher spatial frequency). The characteristic difference between human and insect responses was unaffected by correcting for the stimulus distortion caused by short viewing distances in insects. These findings constitute stronger evidence that the undetectable noise effect reported earlier is a genuine difference between human and insect motion processing, and not an artefact caused by differences in experimental paradigms.
Project number: 115
Librerías Matlab para la presentación y procesamiento de sonidos e imágenes 2D y 3D en el aula
(2020) Serrano Pedraza, Ignacio; Sierra Vázquez, Vicente; Arranz Paraíso, Sandra; Luna del Valle, Raul; López Bascuas, Luis Enrique; Campos Bueno, José Javier
El resultado del Proyecto consta de 15 programas en Matlab con más de cien funcionalidades. Ocho están dedicados a demostraciones para el estudio del Sistema Auditivo humano (e.g. diferentes tipos de espectrogramas, Transformadas Wavelet, el filtro gammatono, el filtro gammachirp, etc), cinco están dedicados a al estudio del Sistema Visual (e.g. determinación de la estereoagudeza, de la sensibilidad al contraste, de la sensibilidad a la disparidad, etc.) y dos están dedicados a la Colorimetría de luces y objetos. En el Anexo de este documento se presentan capturas de los quince programas con una breve descripción de las características, objetivos y funcionalidades de cada programa. Todos los programas están sujetos a mejoras que se irán añadiendo en sucesivas versiones. Las actualizaciones de estos programas se harán accesibles en esta página web: https://www.ucm.es/serranopedrazalab/.
Comparing Bias and Precision of Stochastic and Bayesian Procedures for Disparity Threshold Estimation
(2019) Arranz Paraíso, Sandra; Chacón Gómez, José Carlos; Serrano Pedraza, Ignacio
Visual motion discrimination experiments reveal small differences between males and females
(Vision Research, 2023) Bachtoula González, Omar; Arranz Paraíso, Sandra; Luna, Raúl; Serrano Pedraza, Ignacio
Recent results have shown that males have lower duration thresholds for motion direction discrimination than females. Measuring contrast thresholds, a previous study has shown that males have a greater sensitivity to fine details and fast flickering stimuli than females, and that females have a higher sensitivity to low spatial frequencies modulated at low temporal frequencies. Here, we present the data of a contrast-detection motion discrimination experiment and a reanalysis of four different motion discrimination experiments where we compare duration thresholds for males and females using different spatial frequencies, stimulus sizes, contrasts, and temporal frequencies (in two experiments, motion surround suppression was measured). Results from the main experiment and the reanalysis show that, in general, the association between sex and contrast and duration thresholds for motion discrimination is not significant, with males and females showing similar data patterns. Only the reanalysis of one out of four studies revealed different duration thresholds between males and females paired with a strong effect size supporting previous results in the literature, although motion surround suppression was identical between groups. Importantly, most of our results do not show significant differences between males and females in contrast and duration thresholds, suggesting that the sex variable may not be as relevant as previously claimed when testing visual motion discrimination.
Is there a correlation between psychophysical visual surround suppression and IQ?
(2016) Arranz Paraíso, Sandra; Serrano Pedraza, Ignacio
When Perception From Two Eyes Is Slower Than From One Eye: Reduced Surround Suppression in Monocular Motion Perception
(2019) Arranz Paraíso, Sandra; Read, J CA; Serrano Pedraza, Ignacio
Project number: 223
Desarrollo de software en entorno Matlab para la generación y presentación de sonidos e imágenes 2D y 3D en el aula
(2017) Serrano Pedraza, Ignacio; Sierra Vázquez, Vicente; López Bascuas, Luis Enrique; Campos Bueno, José Javier; Luna del Valle, Raúl; Arranz Paraíso, Sandra
El resultado de este Proyecto de Innovación Docente consta de doce programas en Matlab con más de cien funcionalidades. Cinco programas están dedicados a demonstraciones para el estudio del sistema auditivo humano, seis están dedicados al estudio del sistema visual humano y un programa está dedicado al análisis y explicación de resultados experimentales analizados de acuerdo con la Teoría de Detección de Señales. Estos programas ayudarán al profesor a explicar el análisis de Fourier aplicado a imágenes y sonidos, el concepto de filtro, la técnica de enmascaramiento, el concepto de canal visual, generar estímulos 3D utilizando estereogramas de puntos aleatorios, y a presentar de modo controlado sonidos e imágenes (2D y 3D) en el aula.
Measuring the strength of the interaction between fine and coarse scales on motion discrimination under monocular and binocular viewing
(2021) Arranz Paraíso, Sandra; Serrano Pedraza, Ignacio
The strength of the interaction between fine and coarse scales in motion discrimination is size tuned
(2022) Arranz Paraíso, Sandra; Prados-Rodríguez, Francisco; Serrano Pedraza, Ignacio
Testing the link between visual suppression and intelligence
(PLoS ONE, 2018) Arranz Paraíso, Sandra; Serrano Pedraza, Ignacio
The impairment to discriminate the motion direction of a large high contrast stimulus or to detect a stimulus surrounded by another one is called visual suppression and is the result of the normal function of our visual inhibitory mechanisms. Recently, Melnick et al. (2013), using a motion discrimination task, showed that intelligence strongly correlates with visual suppression (r = 0.71). Cook et al. (2016) also showed a strong link between contrast surround suppression and IQ (r = 0.87), this time using a contrast matching task. Our aim is to test this link using two different visual suppression tasks: a motion discrimination task and a contrast detection task. Fifty volunteers took part in the experiments. Using Bayesian staircases, we measured duration thresholds in the motion experiment and contrast thresholds in the spatial experiment. Although we found a much weaker effect, our results from the motion experiment still replicate previous results supporting the link between motion surround suppression and IQ (r = 0.43). However, our results from the spatial experiment do not support the link between contrast surround suppression and IQ (r = -0.09). Methodological differences between this study and previous studies which could explain these discrepancies are discussed.