Psychophysical Measures Research Articles

Continuous Psychophysics: measuring visual sensitivity by dynamic target tracking

We introduce a novel framework for estimating visual sensitivity using a continuous target-tracking task in concert with a dynamic internal model of human visual performance. In our main experiment, observers used a mouse cursor to track the center of a 2D Gaussian luminance target as it moved in a Brownian walk in a field of dynamic Gaussian luminance noise. To estimate visual sensitivity, we fit a Kalman filter to the tracking data assuming that humans behave roughly as Bayesian ideal observers. Such observers optimally combine prior information with noisy observations to produce an estimate of target location at each point in time. We found that estimates of human sensory noise obtained from the Kalman filter model were highly correlated with traditional psychophysical measures of human sensitivity (R2 > 0.97). Because data can be collected at the display frame rate, the amount of time required to measure sensitivity is greatly reduced relative to traditional psychophysics. While our modeling framework provides principled estimates of sensitivity that are directly comparable with those from traditional psychophysics, easily-computed summary statistics based on cross-correlograms of the tracking data also accurately predict relative sensitivity, and are thus good empirical substitutes for the more computationally-intensive Kalman filter fitting. As a second example, we show contrast sensitivity functions quickly determined using target tracking. Finally, we show that psychophysical reverse-correlation can also be quickly done via tracking. We conclude that dynamic target tracking is a viable and faster alternative to traditional psychophysical methods in many situations. Meeting abstract presented at VSS 2015

Effect of varying CRT refresh rate on the measurement of temporal summation.

To quantify the effect of cathode-tube-ray (CRT) monitor refresh rate on the measurement of the upper limit of complete temporal summation (critical duration) in the peripheral visual field of healthy observers. Contrast thresholds were measured for seven achromatic spot stimuli (diameter 0.48°) of varying duration (nominal values: 10-200 ms) at an eccentricity of 8.8° along the 45°, 135°, 225° and 315° meridians of the visual field in three healthy, psychophysically experienced observers. Stimuli were presented on a CRT display with a refresh rate of 60 and 160 Hz. Contrast thresholds were expressed as contrast energy with stimulus durations being estimated using (1) the sum-of-frames (SOF) method and (2) Bridgeman's method incorporating measurements of phosphor persistence. Estimates of the critical duration were produced using iterative two-phase regression analysis. With stimulus duration expressed as SOF equivalent the critical duration was, on average, 10.6 ms longer with a refresh rate of 60 Hz (mean 45.7 ms, S.D. 10.1 ms) relative to 160 Hz (35.1 ms, S.D. 7.6 ms). When the Bridgeman method was used, minimal differences (1.8 ms) in critical duration values between the two refresh rates (60 Hz: 33.0 ms, S.D. 9.4 ms; 160 Hz: 31.2 ms, S.D. 7.0 ms) were observed. Identical trends were observed in all three subjects. Psychophysical measurements of temporal summation are independent of variations in CRT refresh rate when the Bridgeman method, incorporating measured values of phosphor persistence, is used to estimate stimulus duration. This has significant implications for the specification of stimulus duration in psychophysical studies of vision employing conventional display monitors.

Psychophysical Measurement of Wet and Clingy Sensation of Fabrics by the Volar Forearm Test

ABSTRACTWet and clingy sensation caused by fabric is activated by thermoreceptors and mechanoreceptors and is critical to wearers’ thermophysiological and tactile comfort. This study aims at quantifying the absolute threshold for wet and clingy sensation of apparel fabrics using a psychophysical approach and measuring the residual moisture left on skin through a physical approach. A volar forearm test is proposed where water supply and controlled fabric movement are used to simulate sweating and body movement during wear. The results show that the volar forearm test has good within‐judge reliability, between‐judge consistency and high sensitivity. The difference in absolute threshold of wet and clingy sensation of fabrics can be attributed to the difference in wicking rate, evaporation rate, geometry and thermal properties of fabrics. The results further suggest that a clingy sensation is triggered when the residual water accumulated on the skin exceeds 0.013 gram, given that the covering fabric is water absorbent. Besides, the absolute threshold for wet and clingy sensation was found strongly correlated with the instrumentally measured water absorption capacity of the fabric. Furthermore, results obtained by the psychophysical threshold method were compared with the psychological wetness rating scale method, and the former was found to be advantageous in terms of testing sensitivity.PRACTICAL APPLICATIONSTo improve living standards, the textile industry is constantly seeking comfortable apparel fabrics, especially for sportswear, intimate apparel and functional clothing when used under extreme conditions or strenuous activities. The wetness comfort is also important for health‐care products since wetness can promote growth of microorganisms, thereby causing dermatitis. In the proposed forearm test, the sweat rate and the degree of fabric movement is adjustable, which simulates varying levels of activity. This study demonstrates the feasibility of using an absolute threshold to assess moisture sensation of apparel fabrics. It may be beneficial to textile/clothing manufacturers to improve existing products or develop new products for specific end uses. Since our study shows that water absorption capacity of fabric has a strong correlation with wet and clingy sensation, instrumental measurement can be employed as a routine fabric performance analysis to substitute the time‐consuming human subjective assessment.

Robotic psychophysics system for assessment, diagnosis and rehabilitation of the neurological causes of falls in the elderly.

Falls are the leading causes of unintentional injuries in the elderly and thus a pose a major hazard to our ageing society. We present the FOHEPO (FOot HEight POsitioning) system to measure, diagnose and eventually rehabilitate ageing-related neurological causes of falls. We hypothesise that both perceptual and motor variability is likely to increase with age and may lead to imprecise perception and movements causing trip overs, the major triggers of falls. Our robotic experimental system automatically measures and tracks different sources of noise in the nervous system: visual perception noise of obstacle height, proprioceptive noise of localising raising one's foot to a desired height, noise in the visual feedback of the foot movements. We developed age-appropriate psychophysical measurement protocols shorter than standard protocols for perceptual and motor accuracy. These quantify individual subjects perceptual and movement accuracy thresholds through their psychometric curves. Therefore, these platform measurements will enable us to estimate fall probabilities quantitatively, i.e. the chance that a foot will clip an obstacle because subjects did not add a sufficient safety factor when clearing it. Potentially, we can use our FOHEPO system in a game-ified setting to rehabilitate elderly users to move with larger safety factors so as to reduce their risks of trip-over.

Viewing distance matter to perceived intensity of facial expressions.

In our daily perception of facial expressions, we depend on an ability to generalize across the varied distances at which they may appear. This is important to how we interpret the quality and the intensity of the expression. Previous research has not investigated whether this so called perceptual constancy also applies to the experienced intensity of facial expressions. Using a psychophysical measure (Borg CR100 scale) the present study aimed to further investigate perceptual constancy of happy and angry facial expressions at varied sizes, which is a proxy for varying viewing distances. Seventy-one (42 females) participants rated the intensity and valence of facial expressions varying in distance and intensity. The results demonstrated that the perceived intensity (PI) of the emotional facial expression was dependent on the distance of the face and the person perceiving it. An interaction effect was noted, indicating that close-up faces are perceived as more intense than faces at a distance and that this effect is stronger the more intense the facial expression truly is. The present study raises considerations regarding constancy of the PI of happy and angry facial expressions at varied distances.

Ergonomic Assessment for Manual Materials Handling of Livestock Feed by Elderly Farmers in Korea

Objective: The purpose of the study is to evaluate appropriate weight for aged farmers in manually handling livestock feed in bags using ergonomic methods.BR Background: In the livestock industry in South Korea, despite the trend of aging of labor manpower, heavy items are still manually handled in many farms. In particular, among stockbreeding works, the handling of feed in bags weighing 25~30kg is reported as a cause of frequent injuries and musculoskeletal system diseases. However, studies on the standard for recommended weight allowed considering the physical characteristics of aged farmers older than 60 years with greatly decreased physical strength and muscle strength are insufficient.BR Method: To evaluate appropriate weight for handling of heavy livestock feed in bags, physical techniques for measuring recognized levels of physical work loads, the NLE (NIOSH lifting equation) a method that is an observation type technique, and an ergonomic modeling technique to predict compressive force imposed on L5/S1 were used. Subjects who participated in the experiment were organized into two groups of males/females with mean age exceeding 60 years, and lifting tasks were evaluated for nine weight levels.BR Results: Based on the results of psychophysical measurement, females showed a tendency of more drastic increases compared to males when weight was over 19kg. The results of estimation of regression models for the weight, 18.0 kg (r²=0.97) and 15.3kg (r²=0.97) were evaluated as stable load for males and females, respectively. In addition, both the observation type evaluation and ergonomic model evaluation showed stable loads in a range of 15~18kg.BR Conclusion: Given the results of the study, the weight of the feed in bags currently distributed to farms can become a cause of not only overexertion but also farm work related disasters such as musculoskeletal disorders and safety accidents. Providing livestock feed in bags weighing not more than 19kg for aged farmers is judged desirable, and managerial improvement for this matter is considered necessary. BR Application: The results of the present study can be utilized as useful data for institutional improvement of the weight of livestock feed in bags.

Ergonomic risk factors in bicycle repairing units at Jabalpur.

Bicycle repairing at Jabalpur in the Madhya Pradesh state of India employs a large number of local youths. In this sector occupational ergonomic issues of Work Related Musculoskeletal Disorders (WMSDs) are a big problem and a threat to this profession. The objective of this study was to identify the different ergonomic risk factors for Work Related Musculoskeletal Disorders (WMSDs) in the job of bicycle repairing. Still photography and video photography was used to record different activities. Different types of non-invasive tools like Rapid Entire Body Assessment (REBA), Rapid Upper Limb Assessment (RULA), and Occupational Repetitive Action Index (OCRA) were used. Psychophysical measures were investigated by rated perceived exertion scale and visual analogue scale. OVAKO scores (4), REBA scores (13/13), RULA scores (8/8) were extremely high, indicating immediate intervention. The results indicate that the different tasks in this profession are in the high risk category and demands immediate ergonomic intervention in the form of re-design of the tools used and work station or/and the design of the work process.

Psychophysical Measurements of Itch and Nociceptive Sensations in an Experimental Model of Allergic Contact Dermatitis

Allergic contact dermatitis (ACD) is a common condition that can significantly affect the quality of life. Contact with allergens results in delayed hypersensitivity reactions involving T lymphocytes, with associated skin inflammation and spontaneous itch and nociceptive sensations. However, psychophysical studies of these sensations are lacking. In the present study, we sensitized 8 healthy volunteers to squaric acid dibutyl ester (SADBE). Two weeks later, 1 volar forearm was challenged with SADBE, and the other with acetone vehicle control. Subsequently, participants rated the maximal perceived intensity of spontaneous itch, pricking/stinging, and burning every 6 to 12 hours for 1 week, using the generalized Labeled Magnitude Scale. In the laboratory, they judged stimulus-evoked sensations within and outside the chemically treated area. The SADBE- but not the acetone-treated skin resulted in 1) localized inflammation, with spontaneous itch and nociceptive sensations peaking at 24 to 48 hours after challenge, 2) alloknesis, hyperknesis, and hyperalgesia to mechanical stimuli that were reduced or eliminated by anesthetic cooling of the SADBE-treated area and restored on rewarming, suggesting that sensations and dysesthesias are dependent on ongoing peripheral neural activity, and 3) enhanced itch to intradermal injection of histamine, BAM8-22, or β-alanine. This experimental model of T-cell-mediated inflammation may prove useful in evaluating potential treatments of itch from ACD. PerspectiveIn a model of allergic contact dermatitis, experimentally applied in humans, psychophysical measurements were obtained of persistent, spontaneous itch and enhanced stimulus-evoked itch and pain sensations. These sensory measurements will be useful in the identification of the neural mechanisms underlying inflammatory itch and pain.

Classical conditioning of analgesic and hyperalgesic pain responses without conscious awareness

Pain reduction and enhancement can be produced by means of conditioning procedures, yet the role of awareness during the acquisition stage of classical conditioning is unknown. We used psychophysical measures to establish whether conditioned analgesic and hyperalgesic responses could be acquired by unseen (subliminally presented) stimuli. A 2 × 2 factorial design, including subliminal/supraliminal exposures of conditioning stimuli (CS) during acquisition/extinction, was used. Results showed significant analgesic and hyperalgesic responses (P < 0.001), and responses were independent of CS awareness, as subliminal/supraliminal cues during acquisition/extinction led to comparable outcomes. The effect was significantly larger for hyperalgesic than analgesic responses (P < 0.001). Results demonstrate that conscious awareness of the CS is not required during either acquisition or extinction of conditioned analgesia or hyperalgesia. Our results support the notion that nonconscious stimuli have a pervasive effect on human brain function and behavior and may affect learning of complex cognitive processes such as psychologically mediated analgesic and hyperalgesic responses.

Material properties derived from three-dimensional shape representations

Retinal image structure is due to a complex mixture of physical sources that includes the surface’s 3D shape, light-reflectance and transmittance properties, and the light field. The visual system can somehow discriminate between these different sources of image structure and recover information about the objects and surfaces in the scene. There has been significant debate about the nature of the representations that are used to derive surface reflectance properties such as specularity (gloss). Specularity could be derived either directly from 2D image properties or by exploiting information that can only be derived from representations in which 3D shape has been made explicit. We recently provided evidence that 3D shape information can play a critical role in the perception of material specularity, but the shape manipulation in our prior study also significantly changed 2D image properties (Marlow, Todorović, & Anderson, 2015). Here, we held fixed all monocularly visible 2D image properties and manipulated 3D shape stereoscopically. When binocularly fused, the depicted 3D shapes induced striking transformations in the surfaces’ apparent material properties, which vary from matte to ‘metallic’. Our psychophysical measurements of perceived specularity reveal that 3D shape information can play a critical role in material perception for both singly-curved surfaces and more complex geometries that curve in two directions. These results provide strong evidence that the perception of material specularity can depend on physical constraints derived from representations in which three-dimensional shape has been made explicit.

Importance of cochlear health for cochlear-implant function

In humans with cochlear implants, functional measures show considerable variation from one stimulation site to another along the electrode array. Our research has demonstrated that (1) the across-site patterns of the functional data are stable over time but differ across subjects; and (2) the across-site patterns are measure specific. These observations are consistent with the hypotheses that implant performance at a given stimulation site is dependent on specific conditions near the site, and that the various functional measures do not all depend on the same conditions. However, we lack direct evidence as to the specific conditions leading to the site-specific differences in performance in humans. Studies in our guinea pig laboratory and elsewhere have demonstrated highly significant correlations between psychophysical or electrophysiological measures of implant function and anatomical measures of cochlear health. Furthermore, the correlated anatomical features differ across functional measures. Finally, some functional measures that are correlated with anatomical measures of cochlear health in animals are predictive of speech recognition ability in human implant users. The data support efforts to preserve and/or restore the health of the implanted cochlea. [This work was supported by NIH/NIDCD grants R01 DC010786, R01 DC010412, and P30 DC05188, and a contract from MED-EL.]

The Affective Modulation of Exercise Task Performance: Rating the Urge‐to‐Stop

Exercise performance is the integration of the physical load, the physiological response and the psychophysiological assessment of the task. Affective state modulates perceptions and motivation for the task performance. We hypothesized that the subject's rating of their Urge‐to‐Stop (RUS) in a backpack walking task will be modulated by affective responses and there will be subgroups of high responders (HiR) vs. low responders (LoR). Each subject participated in a control (no backpack weight) and experimental trial (backpack weight=40% body weight). Subjects completed a 1.6 mile exercise task on a treadmill with 8 periodic inclines of 0.1 mile. SAM scores were obtained before and after the walking task. Participants O2 consumption (VO2), CO2 production (VCO2), heart rate (HR), respiratory rate (RR) and psychophysical perception measures were recorded at the end of each incline. There were no significant perceptual differences among participants with the control task. There were significant differences in subject perceptual of RUS with experimental task. There were 2 subgroups with significant differences in RUS. The RUS increase during the loaded backpack trial in LoR was significantly less than HiR. There were no significant HiR‐LoR differences in the HR, RR, VO2 and VCO2 response to the increased load exercise tasks. SAM results for the HiR had decreased valence, increased arousal and decreased control. These results suggest that RUS during an exercise task includes an affective perceptual element and HiR greater affective responses to the task may have contributed to a higher RUS. These results also suggest the affective state of the participant is a determinant of the subject task motivation and may determine, in part, exercise performance.

Continuous psychophysics: Target-tracking to measure visual sensitivity.

We introduce a novel framework for estimating visual sensitivity using a continuous target-tracking task in concert with a dynamic internal model of human visual performance. Observers used a mouse cursor to track the center of a two-dimensional Gaussian luminance blob as it moved in a random walk in a field of dynamic additive Gaussian luminance noise. To estimate visual sensitivity, we fit a Kalman filter model to the human tracking data under the assumption that humans behave as Bayesian ideal observers. Such observers optimally combine prior information with noisy observations to produce an estimate of target position at each time step. We found that estimates of human sensory noise obtained from the Kalman filter fit were highly correlated with traditional psychophysical measures of human sensitivity (R2 > 97%). Because each frame of the tracking task is effectively a "minitrial," this technique reduces the amount of time required to assess sensitivity compared with traditional psychophysics. Furthermore, because the task is fast, easy, and fun, it could be used to assess children, certain clinical patients, and other populations that may get impatient with traditional psychophysics. Importantly, the modeling framework provides estimates of decision variable variance that are directly comparable with those obtained from traditional psychophysics. Further, we show that easily computed summary statistics of the tracking data can also accurately predict relative sensitivity (i.e., traditional sensitivity to within a scale factor).

Age-Related Changes in Cognitive and Sensory Processing: Focus on Middle-Aged Adults.

The purpose of this article was to examine the effects of age on (a) various psychophysical measures of threshold sensitivity and temporal processing in hearing, vision, and touch and (b) measures of cognitive processing as assessed by the Wechsler Adult Intelligence Scale–Third Edition (Wechsler, 1997). Age group differences and correlations with age were examined, as were associations among age, sensory processing, and cognition. The group analyses showed significant differences on most sensory and cognitive measures such that middle-aged adults performed significantly worse than young adults and significantly better than older adults. Correlations of performance with age were also significant when analyses were restricted to just the young and middle-aged adults. Last, sensory processing, but not age, was significantly correlated with cognitive processing when analyses were restricted to just the young and middle-aged adults. Middle-aged adults experienced declines in both sensory and cognitive processing. The declines in both the cognitive and sensory domains were such that, for most measures in each domain, the performance of middle-aged adults fell somewhere between that of young and older adults.

Sensitivity of the hearing system to the velocity of auditory motion: Discrimination thresholds and mismatch negativity

The parallel psychophysical and MMN study focused at the sensitivity of human hearing system to variations in velocity of sound image movement. The motion of sound stimuli with various velocities in the 450 deg/s to 732 deg/s range in increments of 6 deg/s to the left or to the right from the head midline was simulated by introducing linear changes of interaural delay into dichotic stimuli. The psychophysical experiments were designed according to the 2-alternative forced choice paradigm. The subjects were presented by pairs of moving stimuli and were asked to decide which moved faster. The stimuli created for the present study ensured that the subjects performed the discrimination task without relying on associated cues of sound displacement or duration. The psychophysical measures were compared with electrophysiological indexes of sound processing (auditory evoked responses (ERPs) and mismatch negativity (MMN)). Significant MMN was elicited by the difference of 170 deg/s between the reference and test velocity, which corresponded to the relative velocity increase of 38%. At the same time, the difference thresholds for velocity were much higher and exceeded 50%. The results suggest that MMN magnitude depended on the velocity difference between standard and deviant stimuli and was more sensitive to velocity difference than psychophysical measure.

Retinal response to departure from perfect power coupling: implications for the Stiles–Crawford effect

Maximum power transfer occurs in an oscillatory system driven by an external periodic force matching the natural frequency. Here, we analyze the role of matching in the biological phenomenon of waveguiding of light in a photoreceptor cone. When the fraction of light power that is not able to be coupled to a fundamental mode of a foveal cone is computed, it is found that the mismatch is proportional to the degree of departure from the perfect matching for one hundred percent coupling. Thus, Stiles–Crawford effect of the first kind is shown to be the response of the retina to departure from perfect matching. We show by correlating how the diminution in luminous efficiency recorded in psychophysical measurements for beams entering the pupil mm from the point of optimum efficiency in Stiles–Crawford effect of the first kind is due to a departure of either six or one-sixth times from this perfect match. The Stiles–Crawford function is recreated by interpreting perfect matching for axial entry of the beam and proportionate mismatching for corresponding degree of peripheral entries. Now the fundamental question is: Does a biological system respond by decreasing the efficiency by same amount irrespective of increase or decrease so long the product of departures from the value for optimum efficiency is unity?

Abstract T P112: The Effect of Monoaminergic Drugs on Motor Cortex Excitability, Motor Performance and Psychophysics

INTRODUCTION: The benefit of pharmacologic augmentation of stroke recovery remains unclear. As post-stroke motor recovery depends on training-dependent plasticity, we wanted to test the effect of these drugs on the excitability of primary motor cortex (M1), kinematic and psychophysical measures. METHODS: Nine able-bodied individuals (4 males) participated in 4 test sessions at least 1 week apart during which they were administered one oral dose of 4 different medications: placebo (P), amphetamine 10mg (A), methylphenidate 20mg (M), carbidopa/levodopa 25/100mg (D). We used transcranial magnetic stimulation (TMS) to measure the effects of the different drugs on M1 excitability. Motor evoked potentials (MEP) were elicited using TMS at intensities of 35-80% of maximum stimulator output. The Boltzmann function was calculated for MEP amplitudes and compared across the 4 drug conditions. The effects of the drugs on psychophysics and movement kinematics were captured by a 2d accelerometer mounted on the dorsum of the hand. We measured the reaction time and the peak acceleration and dispersion of directions of auditory paced ballistic wrist extension movements. RESULTS: Comparison of the 4 different equations for the Boltzmann sigmoid curve where R max represents the maximum MEP amplitude; k, the slope of the curve; and S50, the intensity that produced half of the maximum MEP amplitude revealed significant differences between drug conditions. Compared to P, A led to a significant decrease in the maximum MEP amplitude (p= 0.00015), while D increased it (p=0.013). The other two parameters were similar to placebo. M had no effect on any of the three parameters. The different drugs had no statistically significant effect on the kinematic measures or reaction time. CONCLUSIONS: These results indicate that the neuromodulatory effect of drugs on M1 excitability differs, which may point to different mechanisms mediating the beneficial effects of these drugs on functional recovery after stroke. It would also support the notion that the beneficial effect of the drugs on recovery is likely due to improved kinematics or psychophysics of executions during training.

Generality and specificity in the effects of musical expertise on perception and cognition

Performing musicians invest thousands of hours becoming experts in a range of perceptual, attentional, and cognitive skills. The duration and intensity of musicians’ training – far greater than that of most educational or rehabilitation programs – provides a useful model to test the extent to which skills acquired in one particular context (music) generalize to different domains. Here, we asked whether the instrument-specific and more instrument-general skills acquired during professional violinists’ and pianists’ training would generalize to superior performance on a wide range of analogous (largely non-musical) skills, when compared to closely matched non-musicians. Violinists and pianists outperformed non-musicians on fine-grained auditory psychophysical measures, but surprisingly did not differ from each other, despite the different demands of their instruments. Musician groups did differ on a tuning system perception task: violinists showed clearest biases towards the tuning system specific to their instrument, suggesting that long-term experience leads to selective perceptual benefits given a training-relevant context. However, we found only weak evidence of group differences in non-musical skills, with musicians differing marginally in one measure of sustained auditory attention, but not significantly on auditory scene analysis or multi-modal sequencing measures. Further, regression analyses showed that this sustained auditory attention metric predicted more variance in one auditory psychophysical measure than did musical expertise. Our findings suggest that specific musical expertise may yield distinct perceptual outcomes within contexts close to the area of training. Generalization of expertise to relevant cognitive domains may be less clear, particularly where the task context is non-musical.

Olfactory and gustatory functions and its relation to body weight

In the present study we investigated the influence of body weight as defined by BMI on gustatory and olfactory perception. A total of 66 healthy adults (41 females; 25 males) participated in psychophysical measurements using the “Sniffin' Sticks” test and “Taste Strips” test. Odor thresholds as well as discrimination and identification performance were determined. Tests of gustatory function involved the identification and thresholds of sweet, sour, salty, or bitter taste. In this study, all subjects were healthy participants in a middle age range (between 20 and 56years of age). Persons with an extreme BMI value were excluded.Subjects were classified according to their BMI in four groups: (1) 15–19.9kg/m, (2) 20–24.9kg/m, (3) 25–29.9kg/m, and (4) >30kg/m. We did not observe an overall effect of BMI on general sensory sensitivity. There was a significant influence of BMI on olfactory thresholds (F(3,62)=2.79; p<0.047) which increased with increasing BMI. In a similar line, the gustatory thresholds for “salty” were significantly higher with higher BMI (F(3,62)=3.06; p<0.035). Olfactory discrimination and identification was not affected by BMI. Thresholds for odor and sweet or salty taste were also correlated.Our data show that body weight influences gustatory and olfactory perception in healthy adults. Increasing BMI is associated with a decrease in olfactory and taste sensitivity. These findings may have implications for the understanding of pathophysiological mechanisms in patients.

The Subjective Magnitudes of Adverbs Followed by Adjectives : The Evaluation in Two Different Psychophysical Measurements

The Subjective Magnitudes of Adverbs Followed by Adjectives : The Evaluation in Two Different Psychophysical Measurements