scholarly journals Contrast normalisation masks natural expression-related differences and artificially enhances the perceived salience of fear expressions.

2020 ◽  
Author(s):  
Abigail Webb ◽  
Paul Hibbard
Keyword(s):  
Emotional Expressions ◽  
Fourier Amplitude ◽  
Threat Bias ◽  
Apparent Contrast ◽  
Naturally Occurring ◽  
Spatial Frequencies ◽  
Amplitude Spectra ◽  
High Level ◽  
Natural Expression ◽  
Lower Contrast

Fearful facial expressions tend to be more salient than other expressions. This threat bias is to some extent driven by simple low-level image properties, rather than the high-level emotion interpretation of stimuli. It might be expected therefore that different expressions will, on average, have different physical contrasts. However, studies tend to normalise stimuli for RMS contrast, potentially removing a naturally-occurring difference in salience. We assessed whether images of faces differ in both physical and apparent contrast across expressions. We measured physical RMS contrast and the Fourier amplitude spectra of 5 emotional expressions prior to contrast normalisation. We also measured expression-related differences in perceived contrast. Fear expressions have a steeper Fourier amplitude slope compared to neutral and angry expressions, and consistently significantly lower contrast compared to other faces. This effect is more pronounced at higher spatial frequencies. With the exception of stimuli containing only low spatial frequencies, fear expressions appeared higher in contrast than a physically matched reference. These findings suggest that contrast normalisation artificially boosts the perceived salience of fear expressions; an effect that may account for perceptual biases observed for spatially filtered fear expressions.

scholarly journals Contrast normalisation masks natural expression-related differences and artificially enhances the perceived salience of fear expressions.

2020 ◽  
Author(s):  
Abigail Webb
Keyword(s):  
Emotional Expressions ◽  
Fourier Amplitude ◽  
Threat Bias ◽  
Apparent Contrast ◽  
Naturally Occurring ◽  
Spatial Frequencies ◽  
Amplitude Spectra ◽  
High Level ◽  
Natural Expression ◽  
Lower Contrast

Fearful facial expressions tend to be more salient than other expressions. This threat bias is to some extent driven by simple low-level image properties, rather than the high-level emotion interpretation of stimuli. It might be expected therefore that different expressions will, on average, have different physical contrasts. However, studies tend to normalise stimuli for contrast, potentially removing a naturally-occurring difference in salience. We assessed whether images of faces differ in both physical and apparent contrast across expressions. We measured physical contrast and the Fourier amplitude spectra of 5 emotional expressions prior to contrast normalisation. We also measured expression-related differences in perceived contrast. Fear expressions have a steeper Fourier amplitude slope compared to neutral and angry expressions, and consistently significantly lower contrast compared to other faces. This effect is more pronounced at higher spatial frequencies. With the exception of stimuli containing only low spatial frequencies, fear expressions appeared higher in contrast than a physically matched reference. These findings suggest that contrast normalisation artificially boosts the perceived salience of fear expressions; an effect that may account for perceptual biases observed for spatially filtered fear expressions.

scholarly journals Contrast normalisation masks natural expression-related differences and artificially enhances the perceived salience of fear expressions.

2020 ◽  
Author(s):  
Abigail Webb ◽  
Paul Hibbard
Keyword(s):  
Facial Expressions ◽  
Emotional Expressions ◽  
Fourier Amplitude ◽  
Low Level ◽  
Naturally Occurring ◽  
Spatial Frequencies ◽  
Natural Expression ◽  
Lower Contrast

Fearful facial expressions tend to be more salient than other expressions. This threatbias is to some extent driven by simple low-level image properties, rather than thehigh-level emotion interpretation of stimuli. It might be expected therefore that differentexpressions will, on average, have different physical contrasts. However, studies tendto normalise stimuli for contrast, potentially removing a naturally-occurring difference insalience. We assessed whether images of faces differ in both physical and apparentcontrast across expressions. We measured physical contrast and the Fourieramplitude spectra of 5 emotional expressions prior to contrast normalisation. We alsomeasured expression-related differences in perceived contrast. Fear expressions havea steeper Fourier amplitude slope compared to neutral and angry expressions, andconsistently significantly lower contrast compared to other faces. This effect is morepronounced at higher spatial frequencies. With the exception of stimuli containing onlylow spatial frequencies, fear expressions appeared higher in contrast than a physicallymatched reference. These findings suggest that contrast normalisation artificiallyboosts the perceived salience of fear expressions; an effect that may account forperceptual biases observed for spatially filtered fear expressions.

scholarly journals SHINE_color: controlling low-level properties of colorful images

2021 ◽  
Author(s):  
Rodrigo Dal Ben
Keyword(s):  
Cognitive Abilities ◽  
Visual Stimuli ◽  
Cognitive Effort ◽  
Pupil Dilation ◽  
Experimental Setting ◽  
Fourier Amplitude ◽  
Experimental Room ◽  
Low Level ◽  
Amplitude Spectra ◽  
High Level

Pupil dilation responses can be used to investigate an array of cognitive abilities across the lifespan. Whereas it is a versatile measure of high-level abilities, pupil dilation can be greatly affected by low-level properties of stimuli and experimental setting such as luminance of visual stimuli and experimental room. One powerful way to control low-level properties of experimental stimuli is to use the SHINE toolbox for MATLAB (Willenbockel et al., 2010). This toolbox contains a set of functions that allows users to precisely specify luminance and contrast, histogram, and Fourier amplitude spectra of visual stimuli. These parametric manipulations minimize potential low-level confounds when investigating higher-level processes (e.g., cognitive effort, recognition). However, SHINE only works with greyscale images. Whereas this serves well to many research purposes, other research goals might benefit from colorful images. Here, we describe the SHINE_color, an adaptation of SHINE that allow users to perform all operations from SHINE toolbox to colorful images.

Experimental Prediction of the Evolution of Cefepime Resistance From the CMY-2 AmpC β-Lactamase

Genetics ◽  
2003 ◽  
Vol 164 (1) ◽  
pp. 23-29
Author(s):  
Miriam Barlow ◽  
Barry G Hall
Keyword(s):  
Good Predictor ◽  
Evolutionary Potential ◽  
Biochemical Activity ◽  
Class A ◽  
Naturally Occurring ◽  
Experimental Prediction ◽  
Lactam Antibiotic ◽  
High Level ◽  
Level Resistance

Abstract Understanding of the evolutionary histories of many genes has not yet allowed us to predict the evolutionary potential of those genes. Intuition suggests that current biochemical activity of gene products should be a good predictor of the potential to evolve related activities; however, we have little evidence to support that intuition. Here we use our in vitro evolution method to evaluate biochemical activity as a predictor of future evolutionary potential. Neither the class C Citrobacter freundii CMY-2 AmpC β-lactamase nor the class A TEM-1 β-lactamase confer resistance to the β-lactam antibiotic cefepime, nor do any of the naturally occurring alleles descended from them. However, the CMY-2 AmpC enzyme and some alleles descended from TEM-1 confer high-level resistance to the structurally similar ceftazidime. On the basis of the comparison of TEM-1 and CMY-2, we asked whether biochemical activity is a good predictor of the evolutionary potential of an enzyme. If it is, then CMY-2 should be more able than the TEMs to evolve the ability to confer higher levels of cefepime resistance. Although we generated CMY-2 evolvants that conferred increased cefepime resistance, we did not recover any CMY-2 evolvants that conferred resistance levels as high as the best cefepime-resistant TEM alleles.

Spectral characteristics of central Nevada microearthquakes

1970 ◽  
Vol 60 (5) ◽  
pp. 1547-1559 ◽  
Author(s):  
Bruce M. Douglas ◽  
Alan Ryall ◽  
Ray Williams
Keyword(s):  
Spectral Characteristics ◽  
Propagation Path ◽  
Seismic Signals ◽  
Fourier Amplitude ◽  
Recording Site ◽  
Focal Distance ◽  
Amplitude Spectra ◽  
Spectral Frequency ◽  
Group Characteristics ◽  
Event Magnitude

Abstract Fourier amplitude spectra were computed for 40 central Nevada microearthquakes, selected to consider, independently, effects of azimuth and distance from known sources. Spectra were averaged for groups of events to eliminate peculiarities of individual records and emphasize group characteristics. Spectral characteristics did not behave systematically as a function of azimuth from the recording site to the source, but peak spectral frequency was found to correlate strongly with event magnitude and to some degree also with focal distance. These preliminary results suggest that recordings of small earthquakes and microearthquakes can be used to provide detailed information on the character of seismic signals related to properties of the source and propagation path.

Approximate method to estimate the short-period strong motion spectra on bedrock

1981 ◽  
Vol 71 (2) ◽  
pp. 491-505
Author(s):  
Katsuhiko Ishida
Keyword(s):  
Earthquake Swarm ◽  
Strong Motion ◽  
Fourier Amplitude ◽  
Period Range ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Short Period ◽  
Amplitude Spectra ◽  
Low Pass ◽  
Parkfield Earthquake

abstract The methodology to estimate the strong motion Fourier amplitude spectra in a short-period range (T ≦ 1 to 2 sec) on a bedrock level is discussed in this paper. The basic idea is that the synthetic strong motion Fourier spectrum F˜A(ω) calculated from smoothed rupture velocity model (Savage, 1972) is approximately similar to that of low-pass-filtered strong earthquake ground motion at a site in a period range T ≧ 1 to 2 sec: F˜A(ω)=B˜(ω)·A(ω). B˜(ω) is an observed Fourier spectrum on a bedrock level and A(ω) is a low-pass filter. As a low-pass filter, the following relation, A ( T ) = · a · T n a T n + 1 , ( T = 2 π / ω ) , is assumed. In order to estimate the characteristic coefficients {n} and {a}, the Tokachi-Oki earthquake (1968), the Parkfield earthquake (1966), and the Matsushiro earthquake swarm (1966) were analyzed. The results obtained indicate that: (1) the coefficient {n} is nearly two for three earthquakes, and {a} is nearly one for the Tokachi-Oki earthquake, eight for the Parkfield earthquake, and four for the Matsushiro earthquake swarm, respectively; (2) the coefficient {a} is related with stress drop Δσ as (a = 0.07.Δσ). Using this relationship between {a} and Δσ, the coefficients {a} of past large earthquakes were estimated. The Fourier amplitude spectra on a bedrock level are also estimated using an inverse filtering method of A ( T ) = a T 2 a T 2 + 1 .

Communicating emotions in L2 Chinese: Talk in the dorm during study abroad

2018 ◽  
Vol 4 (2) ◽  
pp. 337-359
Author(s):  
Qian Wu
Keyword(s):  
Study Abroad ◽  
Native Speakers ◽  
Human Interaction ◽  
Emotional Expressions ◽  
Genetic Method ◽  
Naturally Occurring ◽  
Expression Of Emotion ◽  
History Of ◽  
Oral Interaction

AbstractCommunication of emotion is at the heart of human interaction. For second language (L2) learners, the ability to communicate one’s emotion is crucial, especially in the context of study abroad when they are in frequent contact with native speakers. The aim of the case study is to investigate how an American sojourner Puppies and her Chinese roommate Kiki (both pseudonyms) participated in conversational narratives in the dormitory to construct emotions, and how the contextualized interaction facilitated Puppies’ development of a linguistic repertoire for the expression of emotion in Chinese. Informed by Vygotskian sociocultural theory, the study followed the genetic method in tracing the history of Puppies’ Chinese emotional repertoire across the semester, thereby elucidating the language developmental processes in the situated oral interaction. Audio-recorded everyday interaction in the dorm is triangulated by Puppies’ responses to the pre- and post-Mandarin Awareness Interview and interviews with Puppies and Kiki. Analysis revealed that the contextualized dorm talk provided abundant L2 resources for Puppies to develop a L2 emotional repertoire, especially fear-related emotion expressions. A discrepancy in the product of development as gleaned from the Mandarin Awareness Interview, and the process of development as seen in the naturally occurring dorm talk, suggests that Puppies’ use or non-use of local emotional expressions could be mediated by her partial understanding of the forms and the speech style and identity she wished to assume.

scholarly journals The Initial Disparity Vergence Elicited With Single and Dual Grating Stimuli in Monkeys: Evidence for Disparity Energy Sensing and Nonlinear Interactions

2008 ◽  
Vol 100 (5) ◽  
pp. 2907-2918 ◽  
Author(s):  
K. Miura ◽  
Y. Sugita ◽  
K. Matsuura ◽  
N. Inaba ◽  
K. Kawano ◽  
...  
Keyword(s):  
Sine Wave ◽  
Nonlinear Dependence ◽  
One Dimensional ◽  
Quarter Wavelength ◽  
Spatial Frequencies ◽  
Energy Sensing ◽  
The One ◽  
Winner Take All ◽  
Lower Contrast ◽  
Horizontal Grating

We recorded the initial vertical vergence eye movements elicited in monkeys at short latency (∼70 ms) when the two eyes see one-dimensional (1D) horizontal grating patterns that are identical except for a phase difference (disparity) of one-quarter wavelength. With gratings composed of single sine waves, responses were always compensatory, showing Gaussian dependence on log spatial frequency (on average: peak = 0.75 cycles/deg; SD = 0.74; r2 = 0.980) and monotonic dependence on log contrast with a gradual saturation well described by the Naka-Rushton equation (on average: n = 0.89; C50 = 4.1%; r2 = 0.978). With gratings composed of two sine waves whose spatial frequencies were in the ratio 3:5 and whose disparities were of opposite sign (the 3f5f stimulus), responses were determined by the disparities and contrasts of the two sine-wave components rather than the disparity of the features, consistent with early spatial filtering of the monocular inputs before their binocular combination and mediation by detectors sensitive to disparity energy. In addition, responses to the 3f5f stimulus showed a nonlinear dependence on the relative contrasts of the two sine waves. Thus on average, when the contrast of one sine wave was 2.3 times greater than that of the other, the one with the lower contrast was largely ineffective as though suppressed, and responses were determined almost entirely by the sine wave of higher contrast: Winner-Take-All. These findings are very similar to those published previously on the vertical vergence responses of humans, indicating that the monkey provides a good animal model for studying these disparity vergence responses.

scholarly journals Dogs recognize dog and human emotions

2016 ◽  
Vol 12 (1) ◽  
pp. 20150883 ◽  
Author(s):  
Natalia Albuquerque ◽  
Kun Guo ◽  
Anna Wilkinson ◽  
Carine Savalli ◽  
Emma Otta ◽  
...  
Keyword(s):  
Information Processing ◽  
Domestic Dogs ◽  
Emotional Expressions ◽  
Emotional Information ◽  
Auditory Cues ◽  
Cognitive Representations ◽  
Negative Valence ◽  
The Social ◽  
The Face ◽  
High Level

The perception of emotional expressions allows animals to evaluate the social intentions and motivations of each other. This usually takes place within species; however, in the case of domestic dogs, it might be advantageous to recognize the emotions of humans as well as other dogs. In this sense, the combination of visual and auditory cues to categorize others' emotions facilitates the information processing and indicates high-level cognitive representations. Using a cross-modal preferential looking paradigm, we presented dogs with either human or dog faces with different emotional valences (happy/playful versus angry/aggressive) paired with a single vocalization from the same individual with either a positive or negative valence or Brownian noise. Dogs looked significantly longer at the face whose expression was congruent to the valence of vocalization, for both conspecifics and heterospecifics, an ability previously known only in humans. These results demonstrate that dogs can extract and integrate bimodal sensory emotional information, and discriminate between positive and negative emotions from both humans and dogs.

scholarly journals The Binding Ring Illusion: assimilation affects the perceived size of a circular array

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 58 ◽  
Author(s):  
J Daniel McCarthy ◽  
Colin Kupitz ◽  
Gideon P Caplovitz
Keyword(s):  
Visual Processing ◽  
Visual Information ◽  
Circular Array ◽  
Multiple Sources ◽  
Spatial Frequencies ◽  
Constructive Process ◽  
Novel Variant ◽  
Assimilation Process ◽  
Circular Contour ◽  
High Level

Our perception of an object’s size arises from the integration of multiple sources of visual information including retinal size, perceived distance and its size relative to other objects in the visual field. This constructive process is revealed through a number of classic size illusions such as the Delboeuf Illusion, the Ebbinghaus Illusion and others illustrating size constancy. Here we present a novel variant of the Delbouef and Ebbinghaus size illusions that we have named the Binding Ring Illusion. The illusion is such that the perceived size of a circular array of elements is underestimated when superimposed by a circular contour – a binding ring – and overestimated when the binding ring slightly exceeds the overall size of the array. Here we characterize the stimulus conditions that lead to the illusion, and the perceptual principles that underlie it. Our findings indicate that the perceived size of an array is susceptible to the assimilation of an explicitly defined superimposed contour. Our results also indicate that the assimilation process takes place at a relatively high level in the visual processing stream, after different spatial frequencies have been integrated and global shape has been constructed. We hypothesize that the Binding Ring Illusion arises due to the fact that the size of an array of elements is not explicitly defined and therefore can be influenced (through a process of assimilation) by the presence of a superimposed object that does have an explicit size.

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