Perceptual Content Research Articles

The Neural Corelates of Constructing Conceptual and Perceptual Representations of Autobiographical Memories.

Contemporary neurocognitive frameworks propose that conceptual and perceptual content of autobiographical memories-personal past experiences-are processed by dissociable neural systems. Other work has proposed a central role of the anterior hippocampus in initially constructing autobiographical memories, regardless of the content. Here, we report on an fMRI study that utilized a repeated retrieval paradigm to test these ideas. In an MRI scanner, participants retrieved autobiographical memories at three timepoints. During the third retrieval, participants either shifted their focus to the conceptual content of the memory, the perceptual content of the memory, or retrieved the memory as they had done so on previous trials. We observed stronger anterior hippocampal activity for the first retrieval compared with later retrievals, regardless of whether there was a shift in content in those later trials. We also found evidence for separate cortical systems when constructing autobiographical memories with a focus on conceptual or perceptual content. Finally, we found that there was common engagement between later retrievals that required a shift toward conceptual content and the initial retrieval of a memory. This final finding was explored further with a behavioral experiment that provided evidence that focusing on conceptual content of a memory guides memory construction, whereas perceptual content adds precision to a memory. Together, these findings suggest there are distinct content-oriented cortical systems that work with the anterior hippocampus to construct representations of autobiographical memories.

Verbal disputes about the content of experience

Abstract A verbal dispute is one in which the disputants agree on all of the facts about the intended subject matter of the dispute and disagree only about how to use certain terms. This paper explores the possibility that the dispute between particularists and generalists about the contents of perceptual experience is a verbal dispute. The aim is less to provide a knockdown argument for the conclusion that this dispute is merely verbal than to show how difficult it is to uncover a substantive dispute between the two sides. A concluding section asks whether the argument generalizes beyond the particularism/generalism dispute to other prominent disputes in contemporary philosophy of mind.

A New Distance Measurement Method for Perceptual Image Hashing

A large number of perceptual image hashing schemes have been developed in recent decades, and they usually calculated the hash distances using Euclidean distance, correlation coefficient, normalized Hamming distance, etc. These hash distances are not customized measurements for hash sequences, which are all single values. To this end, a new distance measurement method, i.e. a distance vector instead of a single value, is proposed in this paper. Since a hash sequence can be regarded as the compressed representation of image perceptual content, the correlation between images is maintained between hash sequences. In our method, the correlation between hash sequences is captured by residuals and co-occurrence matrix to form a distance vector. The correlation differences between perceptually similar and distinct images can be captured in the obtained distance vectors. Using a binary classifier, it is easy to classify the distance vectors of perceptually similar image pairs and perceptually distinct image pairs. As a result, content authentication accuracy of perceptual image hashing can be effectively increased, which is verified by experimental results.

A robust self-supervised image hashing method for content identification with forensic detection of content-preserving manipulations

Image content identification systems have many applications in industry and academia. In particular, a hash-based content identification system uses a robust image hashing function that computes a short binary identifier summarizing the perceptual content in a picture and is invariant against a set of expected manipulations while being capable of differentiating between different pictures. A common approach to designing these algorithms is crafting a processing pipeline by hand. Unfortunately, once the context changes, the researcher may need to define a new function to adapt. A deep hashing approach exploits the feature learning capabilities in deep networks to generate a feature vector that summarizes the perceptual content in the image, achieving outstanding performance for the image retrieval task, which requires measuring semantic and perceptual similarity between items. However, its application to robust content identification systems is an open area of opportunity. Also, image hashing functions are valuable tools for image authentication. However, to our knowledge, its application to content-preserving manipulation detection for image forensics tasks is still an open research area. In this work, we propose a deep hashing method exploiting the metric learning capabilities in contrastive self-supervised learning with a new modular loss function for robust image hashing. Moreover, we propose a novel approach for content-preserving manipulation detection for image forensics through a sensitivity component in our loss function. We validate our method through extensive experimentation in different data sets and configurations, validating the generalization properties in our work.

Phenomenal Socialism

Phenomenal socialism says that what we actually, directly, literally perceive is only or primarily instances of high-level phenomenal properties; this paper argues for phenomenal socialism in the weaker, primarily version. Phenomenal socialism is the philosophy of perception that goes with recognitionalism, which is the metaethics that goes with epiphanies. The first part states the recognitionalist manifesto. The second part situates this manifesto relative to some more global concerns, about naturalism, perception, the metaphysics of value, and theory vs. anti-theory in ethics. The third part rehearses two familiar views about the possible contents of perceptual experience, Phenomenal Conservativism and Phenomenal Liberalism. It notes that the usual catalogue omits two other theoretical possibilities, Phenomenal Socialism and Phenomenal Nihilism, and it defends a watered-down form of Phenomenal Socialism from four main objections. The fourth part makes some connections with the epistemology of modality and with the role of the imagination.

Image-to-Image Translation with CNN Based Perceptual Similarity Metrics

Image-to-image translation is the process of transforming images from different domains. Generative Adversarial Networks (GANs), and Convolutional Neural Networks (CNNs) are widely used in image translation. This study aims to find the most effective loss function for GAN architectures and synthesize better images. For this, experimental results were obtained by changing the loss functions on the Pix2Pix method, one of the basic GAN architectures. The exist loss function used in the Pix2Pix method is the Mean Absolute Error (MAE). It is called the L_1metric. In this study, the effect of convolutional-based perceptual similarity CONTENT, LPIPS, and DISTS metrics on image-to-image translation was applied on the loss function in Pix2Pix architecture. In addition, the effects on image-to-image translation were analyzed using perceptual similarity metrics ( L_1_CONTENT, L_1_LPIPS, and L_1_DISTS) with the original L_1 loss at a rate of 50%. Performance analyzes of the methods were performed with the Cityscapes, Denim2Mustache, Maps, and Papsmear datasets. Visual results were analyzed with conventional (FSIM, HaarPSI, MS-SSIM, PSNR, SSIM, VIFp and VSI) and up-to-date (FID and KID) image comparison metrics. As a result, it has been observed that better results are obtained when convolutional-based methods are used instead of conventional methods for the loss function of GAN architectures. It has been observed that LPIPS and DISTS methods can be used in the loss function of GAN architectures in the future

Cortical depth profiles in primary visual cortex for illusory and imaginary experiences

Visual illusions and mental imagery are non-physical sensory experiences that involve cortical feedback processing in the primary visual cortex. Using laminar functional magnetic resonance imaging (fMRI) in two studies, we investigate if information about these internal experiences is visible in the activation patterns of different layers of primary visual cortex (V1). We find that imagery content is decodable mainly from deep layers of V1, whereas seemingly ‘real’ illusory content is decodable mainly from superficial layers. Furthermore, illusory content shares information with perceptual content, whilst imagery content does not generalise to illusory or perceptual information. Together, our results suggest that illusions and imagery, which differ immensely in their subjective experiences, also involve partially distinct early visual microcircuits. However, overlapping microcircuit recruitment might emerge based on the nuanced nature of subjective conscious experience.

Hill on perceptual contents, Thouless properties, and representational pluralism

Part of a symposium on Christopher Hill's book, Perceptual experience. Hill argues that perceptual experiences typically represent objects as having exotic properties that he calls Thouless properties. This and his representational pluralism allow him to attribute less perceptual error than the view that experiences represent simple relational properties (only). However, I think it is plausible that perceptual systems do make these sorts of errors, which although pervasive and systematic, are relatively subtle and perfectly explicable. I also express some concerns about representational pluralism, especially in the context of a representationalist view of the phenomenal character of experience.

Isolating Neural Signatures of Conscious Speech Perception with a No-Report Sine-Wave Speech Paradigm.

Identifying neural correlates of conscious perception is a fundamental endeavor of cognitive neuroscience. Most studies so far have focused on visual awareness along with trial-by-trial reports of task-relevant stimuli, which can confound neural measures of perceptual awareness with postperceptual processing. Here, we used a three-phase sine-wave speech paradigm that dissociated between conscious speech perception and task relevance while recording EEG in humans of both sexes. Compared with tokens perceived as noise, physically identical sine-wave speech tokens that were perceived as speech elicited a left-lateralized, near-vertex negativity, which we interpret as a phonological version of a perceptual awareness negativity. This response appeared between 200 and 300 ms after token onset and was not present for frequency-flipped control tokens that were never perceived as speech. In contrast, the P3b elicited by task-irrelevant tokens did not significantly differ when the tokens were perceived as speech versus noise and was only enhanced for tokens that were both perceived as speech and relevant to the task. Our results extend the findings from previous studies on visual awareness and speech perception and suggest that correlates of conscious perception, across types of conscious content, are most likely to be found in midlatency negative-going brain responses in content-specific sensory areas.

JUSTIFICATION OF PERCEPTUAL KNOWLEDGE: REPRESENTATIONALISM AND DIRECT REALISM

The paper examines two of the most influential approaches to the problem of the justification of perceptual knowledge: representationalism and direct realism, taken in a version of epistemological disjunctivism. The problem itself can be represented as the need to demonstrate that there is a logical connection between a statement about the perception of a certain fact, p, and a statement about the knowledge of p. The article notes that both approaches face the problem of “the silence of the senses.” This problem was pointed out by Ch.Travis, who tried to show that the content of sensory experience is not propositional; senses themselves do not tell us what fact we are dealing with when perceptually interacting with the world. The first part of the article reconstructs the argument from looks that Travis proposed to criticize representationalism. This part demonstrates that we cannot accept representationalism as an approach in the philosophy of perception that successfully overcomes the shortcomings of sense data theory. The main drawback of this theory was its adherence to the myth of the given—the idea that in perceptual experience we are dealing with non-propositional, non-conceptual “raw” data. The second part of the paper notes that Travis’s argument can also be directed against such a version of direct realism as epistemological disjunctivism, since according to representatives of this theory, the content of veridical perceptual experience, being identical with the perceived state of affairs, is propositional. This part also analyzes the response to Travis from such a representative of this theory as J.McDowell. While McDowell rejects propositionalism, he nevertheless insists that the content of perceptual experience must be regarded as conceptual. It allows us to avoid the myth of the given. In conclusion, criticism of McDowell’s approach from the phenomenological position taken by H.Dreyfus is discussed, and it is noted that McDowell’s conceptualism is quite compatible with both phenomenology and enactivism. The enactivist understanding of perception that we find in McDowell leads us to accept the enactivist account of perceptual knowledge, where the foundation of knowledge is action, i.e. something epistemically groundless.

Many-to-One Intentionalism

Intentionalism is the view that perceptual phenomenology depends on perceptual content. The aim of this paper is to make explicit an ambiguity in usual formulations of intentionalism, and to argue in favor of one way to disambiguate it. It concerns whether perceptual phenomenology depends on the content of one and only one representation (often construed as being identical to a certain perceptual experience), or instead depends on a collection of many different representations throughout the perceptual system. We argue in favor of the latter option. Intentionalism so conceived can make better sense of contemporary neuroscience of perception, and is better equipped to confront several influential objections to traditional intentionalism.

The Separability Thesis

Abstract Debates over the metaphysical status of aesthetic properties have persisted for decades in Aesthetics. One question that consistently arises in any discussion of aesthetic properties is whether they are fundamentally evaluative or descriptive in character. Aesthetic properties are often treated as parallel to moral properties which means many philosophers take it for granted that aesthetic properties are fundamentally evaluative. There are some philosophers, like Frank Sibley and Jerrold Levinson, who take the road less traveled and treat aesthetic properties as primarily descriptive in character. In this paper, I outline Levinson’s intriguing view that the evaluative aspect of an aesthetic property can be canceled leaving us with the descriptive essence of the property. I refer to this as the separability thesis. It contends that evaluative reactions to aesthetic properties can be separated from the objective, perceptual content of an aesthetic experience thereby leaving us with the non-evaluative core of the property. I go on to defend the separability thesis from a powerful challenge developed by Rafael De Clercq. Ultimately, I contend that while De Clercq’s argument is clever and insightful it fails to undermine the separability thesis.

Perceptual Bandwagon Effects With “Deep” Imaginary Companions

Studies of the mediating factors of imaginary companions (ICs) in children and adults are well-represented in the literature. However, the nature and structure of behavioral expressions in IC characters have been less formally scrutinized. We examined these issues in a convenience sample of 389 adults. Of these, 155 self-reported childhood ICs and retrospectively characterized their IC phenomenology via a set of 14 items modified from previous research. Rasch analyses showed that IC experiences form a true probabilistic hierarchy whose structure varied little across respondents’ age, gender, having siblings, as well as the respondents’ number of past ICs, or their decision to inform others about their IC. This hierarchy starts with shallow (i.e., ostensibly ‘adaptive or positive’) experiences and transition to deep (i.e., relatively ‘maladaptive or negative’) contents at higher levels. Network analysis suggested that respondents invented ICs primarily to combat feelings of loneliness. However, contrary to the Rasch model, when comparing shallow vs deep IC experients’ answers, positive and negative perceptual contents lost their distinction, thereby severely distorting measurement. These distortions were sufficiently powerful to reliably predict respondents’ group membership. Results derived from retrospective accounts of childhood experiences, which might differ from IC contents and dynamics measured either in real-time or within adult populations. However, these findings suggest that ICs comprise a latent dimension of shallow-to-deep perceptions that might relate to schizotypal or dissociative phenomena manifesting in everyday contexts.

A quantitative textual analysis of the subjective effects of ayahuasca in naïve users with and without depression

Ayahuasca is a brew with psychoactive properties that has been used as an entheogen for centuries, with more recent studies suggesting it is a promising treatment for some clinical disorders. Although there is an emerging scientific literature on its effects, to the best of our knowledge no study has explored the self-reported experiences of first-time ayahuasca users with quantitative textual analysis tools. Accordingly, the current study aimed to analyze the subjective experience of naive individuals with depression and healthy controls after consuming ayahuasca. For this purpose, responses from a subsample of participants from a previous clinical trial to open-ended questions regarding their experience with ayahuasca underwent textual analysis. Data from nine patients with treatment-resistant depression and 20 healthy individuals were included, and quantitative textual analysis was performed using IRaMuTeQ 0.7 alpha 2 and R 3.1.2. The analysis identified five clusters: alterations in the state of consciousness, cognitive changes, somatic alterations, auditory experiences, and visual perceptual content. Additionally, findings suggest specific features of the experience of people with depression with ayahuasca, such as increased aversive bodily reactions. The results are consistent with previous findings indicating central axes of the psychedelic experience, and may inform therapeutic approaches using ayahuasca.

The Unity of Perceptual Content

Abstract Representationalists hold that perceptual experience is a conscious representational state with content, something which is accurate or inaccurate in certain conditions. The most common version of Representationalism takes perceptual content to be singular in the object-place and otherwise consisting of attribution of properties (Singularism/Attributionism). Schellenberg has recently developed a version on which perceptual content is singular even in the property-place in containing a de re mode of presentation of a property-instance (Particularism). In this paper, I show that Particularism faces a version of the problem of the Unity of Perceptual Content. Namely, its supporters haven’t told us how objects can be bound together with property-instances into a content such that it represents them and has accuracy-conditions. Furthermore, I argue that Particularists face an in-principle obstacle in solving it. In contrast, Attributionists can solve the problem and that establishes their view as the only game in town.

The moment of awareness influences the content of awareness in orientation repulsion

Through the neurally evolving process of dynamic contextual modulation of perceptual contents, it remains unclear how the content of awareness is determined. Here we quantified the visual illusion of orientation repulsion, wherein the target appears tilted against the surrounding’s orientation, and examined whether its extent changed when the target awareness was quickened by a preceding flanker. Independently of spatial cueing, repulsion was reduced when the flanker preceded the target by 100 ms compared with when they appeared simultaneously. We confirmed that the preceding flanker quickened the awareness of a nearby target relative to distant ones by 40 ms. Furthermore, the preceding flanker that was greater than 7 degrees away from the target still evoked such reduction of repulsion. These findings imply that the content of awareness is determined by the temporal interaction of two distinct processes: one controls the moment of awareness, and the other represents the perceptual content.

DiffuCom: A novel diffusion model for comment generation

Given that the diffusion model has good advantages in diversity, an increasing number of researchers have recently begun exploring natural language generation. However, despite significant progress in modeling based on text diffusion, there are still several challenges to be overcome in comment tasks. On the one hand, the source sentences in the comment task are long. If each timestep in the diffusion carries and computes the source sentence, it will significantly increase the computational overhead. On the other hand, the diffusion model is essentially an iterative non-autoregressive model, which lacks target decomposition in the decoding. This makes vanilla cross-attention prone to overlook local perceptual content, leading to the problem of poor correlation. To solve the aforementioned problem, we propose a novel diffusion model for comment generation (named DiffuCom). Specifically, DiffuCom employs the transformer-based encoder–decoder structure, encoding only once during the reverse diffusion process, effectively reducing computational overhead. Additionally, we design a context-aware cross-attention module (CACAM) that integrates global and local cross-attention information through a gating mechanism, which more accurately captures relevant fragment information in the source sentence and improves the correlation. Second, self-conditioning technology was introduced in the training process, which can effectively improve the quality of the samples. Furthermore, to enhance the controllability of DiffuCom, we also propose a blended control. It combines class-conditional and classifier guidance by utilizing the difference between training and inference. Extensive experiments on four comment datasets demonstrate that the proposed DiffuCom model can generate comments that are both diverse and relevant.

Perception, force, and content

AbstractPerceptual experiences have presentational phenomenology: we seem to encounter real situations in the course of visual experiences, for instance. The current paper articulates and defends the claim that the contents of at least some perceptual experiences are inherently presentational. On this view, perceptual contents are not always forceless in the way that, say, the propositional content that 2 + 2 = 4 is generally taken to be, as a content that may be asserted or denied or merely supposed; rather, there are perceptual contents such that any mental state or episode which has the relevant content must be one in which things seem to the given subject to be a certain way. Intuitive motivation for the view is presented and an explanatory line of argument in support of it is developed: it is argued that the recognition of inherently presentational perceptual contents allows us to explain certain representational limitations to which ordinary visualizations and other forms of perceptual mental imagery are subject. Some potential objections to the position are explored, leading to further elaboration of it.

Robust image hashing based on multi-view dimension reduction

In the field of multimedia security, image hashing is an effective technology for solving image content identification. Image hashing algorithm aims to map the high dimensional input features onto perceptual hashing values in terms of their perceptual content, in which visually identical images are mapped to similar digital representations. In this paper, we focus on multi-view dimensionality reduction based hashing generation, and propose a novel method, called Multi-view Dimensionality Reduction based Robust Image Hashing (MDRIH). Our MDRIH scheme maps the multi-view features into a compact binary space by considering the complementarity and similarity between image features across these different views. For preprocessing, bilinear interpolation is applied on the host image to adjust to a standard size, and ensure the different images with same hash size. Specifically, in order to improve the robustness of the algorithm against content-preserving operations, multi-view features, including structural features, edge features, and color features are extracted. After that, multi-view dimension reduction is adopted to obtain meaningful low-dimensional information from multi-feature fusion. Finally, the data in low-dimensional subspace is encoded into a compact binary sequence. The experimental results indicate that the proposed hashing method not only preserves the correlation between multiple views and the similarity among different data points within each view, but also achieves a better balance between robustness and discriminability compared to existing hashing methods.

A structuralist theory of phenomenal intentionality

ABSTRACT This paper argues for a theory of phenomenal intentionality (herein referred to as ‘Structuralism’), according to which perceptual experiences only possess intentional content when their phenomenal components are appropriately related to one another. This paper responds to the objections (i) that Structuralism cannot explain why some experiences have content while others do not, or (ii) why contentful experiences have the specific contents that they have. Against (i), I argue that to possess content, an experience must present itself as an experience of something distinct from itself, and that only experiences whose components are suitably structured satisfy this requirement. Against (ii), I argue that Structuralists can provide a deeper explanation of perceptual content than other theories of phenomenal intentionality by showing how the content-determining relations among our experiences depend on the selection pressures under which our perceptual systems developed.