Classical Psychophysics Research Articles

The generalized Robbins–Monro process and its application to psychophysical experiments for threshold estimation

In classical psychophysics, the study of threshold and underlying representations is of theoretical interest, and the relevant issue of finding the stimulus intensity corresponding to a certain threshold level is an important topic. In the literature, researchers have developed various adaptive (also known as ‘up-down’) methods, including the fixed step-size and variable step-size methods, for the estimation of threshold. A common feature of this family of methods is that the stimulus to be assigned to the current trial depends upon the participant’s response in the previous trial(s), and very often a binary response format is adopted. A well-known earlier work of the variable step-size adaptive methods is the Robbins–Monro process (and its accelerated version). However, previous studies have paid little attention to other facets of response variables (in addition to the binary response variable) that could be jointly embedded into the process. This article concerns a generalization of the Robbins–Monro process by incorporating an additional response variable, such as the response time or the response confidence, into the process. We first prove the consistency of the estimator from the generalized method. We then conduct a Monte Carlo simulation study to explore some finite-sample properties of the estimator from the generalized method with either the response time or the response confidence as the variable of interest, and compare its performance with the original method. The results show that the two methods (and their accelerated version) are comparable. The issue of relative efficiency is also discussed.

Soundscape conservation policy focusing on the active listening: An examination based on the case of the Enshu-nada Sea of Japan

This study examines the active nature of listening from the perspective of soundscape conservation. The classical psychophysics views hearing as a passive process, with a stimulus-response relationship. And the ISO definition of soundscape basically follows this scheme. However, this study highlights the significance of active listening, where the listener intentionally seeks information from the sonic environment. In the Enshu region of Japan, which is the case of this research, there is a phenomenon that the sound of waves propagates far and wide, and this knowledge has been passed down through generations tales and folklore. This fact indicates that the people in this region once had a culture in which they actively sought meaning from the sound of waves. In this study, we collaborated with local residents to conduct observations of wave sounds, and some of the collaborators attempted to reconstruct their relationship with wave sounds through the practice of observation. The findings suggest that the act of listening has a significant impact on the formation of context. Therefore, active listening should be considered in soundscape conservation, as well as its relevance to the definition of "context" in the ISO.

Visual motion perception as online hierarchical inference

Identifying the structure of motion relations in the environment is critical for navigation, tracking, prediction, and pursuit. Yet, little is known about the mental and neural computations that allow the visual system to infer this structure online from a volatile stream of visual information. We propose online hierarchical Bayesian inference as a principled solution for how the brain might solve this complex perceptual task. We derive an online Expectation-Maximization algorithm that explains human percepts qualitatively and quantitatively for a diverse set of stimuli, covering classical psychophysics experiments, ambiguous motion scenes, and illusory motion displays. We thereby identify normative explanations for the origin of human motion structure perception and make testable predictions for future psychophysics experiments. The proposed online hierarchical inference model furthermore affords a neural network implementation which shares properties with motion-sensitive cortical areas and motivates targeted experiments to reveal the neural representations of latent structure.

Multiple Criterion and Multiple Stimulus Signal Detection Theory Analysis of Corneal Painful and Cool Pneumatic Stimuli.

Purpose: To evaluate the detectability of pneumatic corneal stimuli and response bias using multi-stimuli multi-criterion signal detection theory (MSDT). Methods: Thirty-six participants were recruited using convenience sampling. A Waterloo Belmonte esthesiometer was used to deliver cold, mechanical, and chemical stimuli to the center of the cornea at three separate study visits. The stimulus type was assigned randomly to each visit at the start of the study. The threshold (baseline for detection theory experiment) for the assigned stimulus type was obtained using the ascending method of limits. In the cold and mechanical MSDT experiments, 100 trials (80 signal (20 each for 4 intensities) and 20 catch trials) were presented in randomized order, and participants responded with a 5-point confidence rating to each trial. In the chemical MSDT experiments, 50 trials (20 signal trials each for two intensities and 10 catch trials) were presented, and responses were provided using 4-point confidence ratings. Detection theory indices were calculated individually and as groups, which were then analyzed using mixed models and paired t-tests. Results: Detectability (da) and the area under the curve (Az) were significantly different between stimulus intensities within each stimulus type (all p < 0.001) but were not different between the stimulus types. Receiver operating characteristics (ROC) curves were separable between the scaled intensities for all stimulus types, and no overlaps were observed in the z-ROC space. The log-likelihood ratio (lnβ) depended on stimulus intensity and psychophysical criterion for all stimulus types. Conclusion: It is feasible to use MSDT for analyzing ocular surface sensory processing and the theory provides insight into the possible bias associated with the use of pneumatic stimuli. With noxious and non-noxious pneumatic stimulation, detectability and criteria vary systematically with stimulus intensity, a result that cannot be derived using classical psychophysics and this highlights the importance of signal detection theory and its approaches in studying ocular surface pain and thermal processing.

Cybernetics, Listening, and Sound-Studio Phenomenotechnique in Abraham Moles’s Théorie de l’information et perception esthétique (1958)

In his Théorie de l’information et perception esthétique (1958), the sociologist of culture Abraham Moles (1920–92) set out to demonstrate the applicability of information theory—a mathematical linchpin of cybernetics—to the arts more generally. Moles drew on classical psychophysics, Gestalt psychology, more modern behavioral psychology, and contemporary psychoacoustic research to advocate a cybernetic model of the perception and creation of art. Moles repeatedly returned to musical examples therein to make his case, leveraging his dual expertise in philosophy and electroacoustics, drawing on formative experiences with Pierre Schaeffer in Paris and Hermann Scherchen at his Gravesano studio. Moles’s interdisciplinary text found many attentive readers across Europe and, following an English translation by the precocious Joel E. Cohen (1966), the Anglophone academic world, but it was valued more as an inspiration for the burgeoning area of “information aesthetics” than as a source of hard scientific evidence. Drawing lightly on positions in the history and philosophy of science articulated by Gaston Bachelard (who supervised Moles’s second PhD, in philosophy) and Hans-Jörg Rheinberger suggests a change of emphasis away from its apparent scientific infelicities and toward Moles’s use of sound-studio technique, which is described with reference to the technologies available to Moles in the years leading up to the publication of the Théorie. Moles manipulated and processed sound recordings—filtering, clipping, and reversing them—in his attempts to empirically estimate the relative proportions of semantic and aesthetic information in speech and music. Moles’s text, when understood in tandem with the traces of his practical experiments in the sound studio, appears as an influential and occasionally prescient exposition of the many possible applications of the principles of information theory to the production, perception, and consumption of sound culture that makes ready use of the latest technical innovations in the media environment of its time.

Power law model for subjective mental workload and validation through air traffic control human-in-the-loop simulation

We provide evidence for a power law relationship between the subjective one-dimensional Instantaneous Self Assessment workload measure (five-level ISA-WL scale) and the radio communication of air traffic controllers (ATCOs) as an objective task load variable. It corresponds to Stevens’ classical psychophysics relationship between physical stimulus and subjective response, with characteristic power law exponent γ of the order of 1. The theoretical model was validated in a human-in-the loop air traffic control simulation experiment with traffic flow as environmental stimulus that correlates positively with ATCOs frequency and duration of radio calls (task load, RC-TL) and their reported ISA-WL. The theoretical predictions together with nonlinear regression-based model parameter estimates expand previously published results that quantified the formal logistic relationship between the subjective ISA measure and simulated air traffic flow (Fürstenau et al. in Theor Issues Ergon Sci 21(6): 684–708, 2020). The present analysis refers to a psychophysics approach to mental workload suggested by (Gopher and Braune in Hum Factors 26(5): 519–532, 1984) that was recently used by (Bachelder and Godfroy-Cooper in Pilot workload esimation: synthesis of spectral requirements analysis and Weber's law, SCL Tech, San Diego, 2019) for pilot workload estimation, with a corresponding power law exponent in the typical range of Stevens’ exponents. Based on the hypothesis of cognitive resource limitation, we derived the power law by combination of the two logistic models for ISA-WL and communication TL characteristics, respectively. Despite large inter-individual variance, the theoretically predicted logistic and power law parameter values exhibit surprisingly close agreement with the regression-based estimates (for averages across participants). Significant differences between logistic ISA-WL and RC-TL scaling parameters and the corresponding Stevens exponents as ratio of these parameters quantify the TL/WL dissociation with regard to traffic flow. The sensitivity with regard to work conditions of the logistic WL-scaling parameter as well as the power law exponent was revealed by traffic scenarios with a non-nominal event: WL sensitivity increased significantly for traffic flow larger than a critical value. Initial analysis of a simultaneously measured new neurophysiological (EEG) load index (dual frequency head maps, DFHM, (Radüntz in Front Physiol 8: 1–15, 2017)) provided evidence for the power law to be applicable to the DFHM load measure as well.

Colors and Things.

How many colors are there? Quoted numbers range from ten million to a dozen. Are colors object properties? Opinions range all the way from of course they are to no, colors are just mental paint. These questions are ill-posed. We submit that the way to tackle such questions is to adopt a biological approach, based on the evolutionary past of hominins. Hunter-gatherers in tundra or savannah environments have various, mutually distinct uses for color. Color differences aid in segmenting the visual field, whereas color qualia aid in recognizing objects. Classical psychophysics targets the former, but mostly ignores the latter, whereas experimental phenomenology, for instance in color naming, is relevant for recognition. Ecological factors, not anatomical/physiological ones, limit the validity of qualia as distinguishing signs. Spectral databases for varieties of daylight and object reflectance factors allow one to model this. The two questions are really one. A valid question that may replace both is how many distinguishing signs does color vision offer in the hominin Umwelt? The answer turns out to be about a thousand. The reason is that colors are formally not object properties but pragmatically are useful distinguishing signs.

Psychology and Behavioral Economics: Focus on the Relationship between Classical Psychophysics and Probability Weighting Functions in Decision Making

Psychology and Behavioral Economics: Focus on the Relationship between Classical Psychophysics and Probability Weighting Functions in Decision Making

Overcoming the Impassable Gulf: Phenomenologizing Psychophysics

Abstract This paper examines Fechner’s (1859) introduction to experimental psychophysics from a phenomenological perspective. Horst’s (2005) analysis is used to demonstrate the phenomenology that is inherent to classical perceptual psychophysics (Fechner’s “outer” psychophysics). Horst argues that the psychophysical event of perception can only be understood as an intentional intertwining of subject and object. From this we move to physiological component of psychophysics—that is, the processes that mediate perceptual awareness (Fechner’s “inner” psychophysics). Drawing primarily on the work of Rosen (2008, 2015), it is argued the phenomenology provides the most appropriate approach for what could be understood as a contemporary psychophysics—one that borrows from recent trends in physics, neuro-physiology, and perception as classical psychophysics had done (or promised to do). This results in a psychiatric neurophenomenology. Examples of the placebo effect and treatment of traumatic brain injury are used to demonstrate the usefulness of a phenomenological psychophysics, one that ultimately meets the demands of Fechner’s original proposal.

Tactile motion lacks momentum.

The displacement of the final position of a moving object in the direction of the observed motion path, i.e. an overestimation, is known as representational momentum. It has been described both in the visual and the auditory domain, and is suggested to be modality-independent. Here, we tested whether a representational momentum can also be demonstrated in the somatosensory domain. While the cognitive literature on representational momentum suggests that it can, previous work on the psychophysics of tactile motion perception would rather predict an underestimation of the perceived endpoint of a tactile stimulus. Tactile motion stimuli were applied on the left and the right dorsal forearms of 32 healthy participants, who were asked to indicate the subjectively perceived endpoint of the stimulation. Velocity, length and direction of the trajectory were varied. Contrary to the prediction based on the representational momentum literature, participants in our experiment significantly displaced the endpoint against the direction of movement (underestimation). The results are thus compatible with previous psychophysical findings on the perception of tactile motion. Further studies combining paradigms from classical psychophysics and cognitive psychology will be needed to resolve the apparently paradoxical predictions by the two literatures.

Eidolons &amp;amp; Capricious Local Sign

Experimental phenomenology probes the meanings and qualities that compose immediate visual experience. In contradistinction, objective methods of classical psychophysics intentionally ignore meanings and qualities, or even awareness as such. Both have their proper uses. Methods of experimental phenomenology that address "equivalence" in a more intricate sense than "visible&#x2013;not visible" or "discriminable&#x2013;not discriminable", require stimuli that go beyond the mere level of magnitude-like parameters and perhaps intrude into the realm of semantics. One investigates the cloud of eidolons, or lookalikes, that mentally surround any image. "Eidolon factories" are based on models of the psychogenesis of visual awareness. The intentional fuzziness of eidolons may derive from a variety of processes. We explore the effects of capricious "local sign". Elsewhere, we formally proposed explicit eidolon factories based on such notions. Here we illustrate some of the effects of capricious local sign.

In-air hearing of the great cormorant (Phalacrocorax carbo).

ABSTRACTMany aquatic birds use sounds extensively for in-air communication. Regardless of this, we know very little about their hearing abilities. The in-air audiogram of a male adult great cormorant (Phalacrocorax carbo) was determined using psychophysical methods (method of constants). Hearing thresholds were derived using pure tones of five different frequencies. The lowest threshold was at 2 kHz: 18 dB re 20 µPa rms. Thresholds derived using signal detection theory were within 2 dB of the ones derived using classical psychophysics. The great cormorant is more sensitive to in-air sounds than previously believed and its hearing abilities are comparable to several other species of birds of similar size. This knowledge is important for our understanding of the hearing abilities of other species of sea birds. It can also be used to develop cormorant deterrent devices for fisheries, as well as to assess the impact of increasing in-air anthropogenic noise levels on cormorants and other aquatic birds.

Towards a psychophysics of interoceptive processes: the measurement of heartbeat detection.

It is difficult to collect objective evidence of interoception. Unlike exteroception, the effective stimuli for interoception are often unknown, and even when identifiable, they are difficult to control experimentally. Furthermore, direct stimulation of the interoceptors is seldom appropriate in human experimentation. Hence, non-invasive behavioural measures of accuracy in heartbeat detection have frequently been adopted to index interoceptive sensitivity. However, there has been little standardization and the two most popular methods for assessing heartbeat detection, heartbeat tracking and two alternative forced choice methods, appear to be biased and of questionable validity. These issues do not arise with other methods that are based on classical psychophysics and that enable subjects to indicate when during the cardiac cycle their heartbeat sensations occur. Not only are these classical methods highly reliable, but they also provide continuous unbiased measures of the temporal locations of heartbeat sensations and the precision with which these sensations are detected.This article is part of the themed issue 'Interoception beyond homeostasis: affect, cognition and mental health'.

Brightness in human rod vision depends on neural adaptation to the quantum statistics of light

In cone-mediated vision, light adaptation obeys Weber's law (constant visual response to constant contrast). Weber adaptation begins in the cones themselves and is well suited to support color constancy. In rod-mediated vision, the visual input consists of a retinal rain of discrete photons. Individual rods do not receive a sufficient number of light quanta within their integration time to light adapt. Instead, light adaptation occurs in post-receptoral circuitry. The nature of this adaptation is still poorly understood. Since the pioneering work of Barlow (1956, 1958), it has been known that psychophysical rod thresholds, when measured with small, brief test probes, increase in proportion to the square-root of adapting intensity, rather than in direct proportion to intensity (Weber's law). A bedrock idea of classical psychophysics ascribes the square-root law to the masking of dim threshold flashes by the naturally occurring variability in the photon rain from the adapting field (Shapley & Enroth-Cugell, 1975). Importantly, this classical explanation does not require actual physiological adaptation and, classically, none was assumed. Here, we present the results of three brightness matching experiments that together demonstrate that the square-root law arises from a neural adaptation (monocular gain control), driven by statistical photon inputs, that influences brightness as well as threshold. The experiments were performed in a haploscope with one eye's adaptive state manipulated and the other eye used as a reference. Our results show that: 1) brightness gain for supra-threshold flashes varies inversely with the standard deviation of the quantal fluctuations from the adapting field; 2) brightness gain is controlled by both the mean and variance of time-integrated photon inputs and changes only slowly (adaptation takes a few minutes). These properties suggest that brightness at low light levels evolved to encode the reliability (signal-to-noise ratio) of sparse statistical light inputs, rather than either luminance or contrast. Meeting abstract presented at VSS 2016

Using detection theory to analyze human decision making and sensory processing

On the 50th anniversary of the publication of Green and Swets’ book “Signal Detection Theory and Psychophysics,” it is fitting to revisit the question of how detection theory models of human decision making can improve our understanding of sensory processing. Classical psychophysics, as conceived by Fechner in 1850, trusts the observer to report sensory experiences without bias. The innovation of signal detection theory (SDT) was to develop methods that do not require the observer to have introspective awareness of internal sensations. Since its introduction, SDT has inspired experimentalists in many fields, and so now it is appropriate to simply refer to “detection theory” (DT) as the models are appropriate to a wide range of experiments, many of which do not involve signals in noise per se. Data from a previously published intensity discrimination task relying upon working memory (Gallun et al., 2012) will be examined in greater detail to show the techniques and benefits of a detection theory approach t...

Leadership and organizational behavior: A thermodynamic inquiry.

This study presents a detailed model of leadership and organizational structures that parallels well-known principles of thermodynamics as they are applied to states of matter. Four types of organizational structure are explored with an emphasis on hierarchical institutions in and with which consulting psychologists spend most of their time. The model describes 3 types of bonding forces based on parasympathetic and sympathetic nervous system arousal and cognitive attributions of respect that parallel those in atomic and molecular physical systems and demonstrates conceptually how variations in their presence and strength create different organizational structures. The application of these forces by leaders, followers, and other stakeholders to the creation and maintenance of human hierarchies is explored in depth. Issues and challenges that the model presents for consulting and organizational psychology are discussed. It is suggested that if the model can be validated by additional research efforts, classical psychophysics may be extended to new domains and that mathematical principles may be developed that can be broadly tested and applied to aspects of leadership and organizational behavior as they have been historically for various social, physical, and chemical systems.

Psychophysics and the Sensory Assessment of Fish

Procedures for sensory evaluation of fish often give the appearance of being empirical, that is, having been developed from practice without any contribution of underlying theory. The fundamental principles of sensory evaluation lie in psychophysics, a branch of psychology. Some textbooks of sensory evaluation have sections on psychophysics, but they are based on what might be called classical psychophysics which is summarized by the Weber/Fechner laws. Contemporary psychophysics has theories and practices which have wider applications in sensory evaluation of foods than classical psychophysics and can be applied to the advantage in the sensory analysis of fish. Three examples from the author's own experience will be presented in this discussion paper: use of the Theory of Signal Detection in evaluating taints; use of similarity ranking methods and multidimensional scaling for grouping fish by sensory properties; and application of current ideas of scaling to the measurement of freshness.

The Euclidean model of measurement in Fechner's psychophysics

Historians acknowledge Euclid and Fechner, respectively, as the founders of classical geometry and classical psychophysics. At all times, their ideas have been reference points and have shared the same destiny of being criticized, corrected, and even radically rejected, in their theoretical and methodological aspects and in their epistemological value. According to a model of measurement of magnitudes which goes back to Euclid, Fechner (1860) developed a theory for psychical magnitudes that opened a lively debate among numerous scholars. Fechner's attempt to apply the model proposed by Euclid to subjective sensation magnitudes--and the debate that followed--generated ideas and concepts that were destined to have rich developments in the psychological and (more generally) scientific field of the twentieth century and that still animate current psychophysics.

Modeling neural mechanisms producing conflicting effects of recent experience on the perception of ambiguous stimuli

Event Abstract Back to Event Modeling neural mechanisms producing conflicting effects of recent experience on the perception of ambiguous stimuli Athena Akrami1* and Alessandro Treves1 1 SISSA, Italy In a diverse range of phenomena, experience with a given stimulus, the prime, affects the perception of a subsequent stimulus, the target. Using classical psychophysics paradigms, it is observed that brief exposure to a stimulus - ranging from tens to hundreds of milliseconds - biases subjects to perceive the target either as dissimilar (adaptation aftereffects) or more similar (priming) to the prime. Thus, in a categorization task, the category boundary may move towards or away from the prime. The duration of the prime and the prime-target asynchrony, as well as the type of intervening mask, affect both the strength and the direction of the effect. In spite of a large body of empirical data on various behavioral outcomes in such experiments, we still lack an explanatory model capable of predicting the crossover from adaptation aftereffect to priming, as emerging in a generic cortical network. We have developed an analytical approach to study the transient dynamics of networks of threshold-linear model neurons that include, as a necessary ingredient of the relevant computational mechanism, a simple feature of pyramidal cell biophysics: firing rate adaptation. The analysis yields the attractor states of the network and the full spectrum of time constants of the transients associated with different steady states. Studying these transients, in the response to external inputs that are morphed between two stored patterns, and affected by previous activity of the network, could shed light on the possible contribution of attractor dynamics to perceptual boundary shifts. The preliminary results show that firing rate adaptation plays the main role to produce adaptation aftereffects in our network, without which one only observes priming effects, if any. The relative duration of target length and adaptation time scale is one of the crucial terms determining the dynamics. The strength of recurrent connection with respect to feedforward inputs is another relevant parameter. Conference: 41st European Brain and Behaviour Society Meeting, Rhodes Island, Greece, 13 Sep - 18 Sep, 2009. Presentation Type: Poster Presentation Topic: Poster presentations Citation: Akrami A and Treves A (2009). Modeling neural mechanisms producing conflicting effects of recent experience on the perception of ambiguous stimuli. Conference Abstract: 41st European Brain and Behaviour Society Meeting. doi: 10.3389/conf.neuro.08.2009.09.072 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 05 Jun 2009; Published Online: 05 Jun 2009. * Correspondence: Athena Akrami, SISSA, Trieste, Italy, akrami@sissa.it Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Athena Akrami Alessandro Treves Google Athena Akrami Alessandro Treves Google Scholar Athena Akrami Alessandro Treves PubMed Athena Akrami Alessandro Treves Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Psychophysics reveals a right hemispheric contribution to body image distortions in women but not men

We tested the hypothesis that the right cerebral hemisphere contributes to the enhanced body image distortions seen in women when compared to men. Using classical psychophysics, 60 right-handed healthy participants (30 women) were briefly presented with size-distorted pictures of themselves, another person (an experimenter), and a non-corporal, familiar object (a coke bottle) to the central, right, and left visual field. Participants had to decide whether the presented stimulus was fatter or thinner than the real body/object, and thus compare the presented picture with the stored representation of the stimulus from memory. From these data we extracted the amount of image distortion at which participants judged the various stimuli to be veridical. We found that right visual field presentations (initial left hemisphere processing) revealed a general “fatter” bias, which was more evident for bodies than for objects. Crucially, a “fatter” bias with own body presentations in the left visual field (initial right hemisphere processing) was only found for women. Our findings suggest that right visual field presentation results in a general size overestimation, and that this overestimation is more pronounced for bodies than for objects. Moreover, the particular “fatter” bias after own body presentations to the left visual field in women supports the notion of a specific role of the right hemisphere in sex-specific body image distortion.