Measuring the World: Olfaction as a Process Model of Perception

Philosophia, https://doi.org/10.1007/s11406-020-00318-y, 2021

According to a common opinion, human olfactory experiences are significantly different from human visual experiences. For instance, olfaction seems to have only rudimentary abilities to represent space; it is not clear whether olfactory experiences have any mereological structure; and while vision presents the world in terms of objects, it is a matter of debate whether there are olfactory object-representations. This paper argues that despite these differences visual and olfactory experiences share a hierarchical subject/property structure. Within this structure, olfactorily experienced odours and visual objects have the same status: they are primary subjects which unify other represented elements into perceptual units.

Attention, perception & psychophysics, 2015

The questions of whether configural and elemental perceptions are competitive or exclusive perceptual processes and whether they rely on independent or dependent mechanisms are poorly understood. To examine these questions, we modified perceptual experience through preexposure to mixed or single odors and measured the resulting variation in the levels of configural and elemental perception of target odor mixtures. We used target mixtures that were spontaneously processed in a configural or an elemental manner. The AB binary mixture spontaneously involved the configural perception of a pineapple odor, whereas component A smelled like strawberry and component B smelled like caramel. The CD mixture produced the elemental perceptions of banana (C) and smoky (D) odors. Perceptual experience was manipulated through repeated exposure to either a mixture (AB or CD) or the components (A and B or C and D). The odor typicality rating data recorded after exposure revealed different influences o...

Philosophia, https://link.springer.com/article/10.1007/s11406-018-0017-3

In the contemporary analytic discussions concerning human olfactory perception, it is commonly claimed that (1) olfactory experiences are representations having content and (2) olfactory experiences represent odours, like coffee odour or vanilla odour. However, despite these common assumptions, there seems to be an ontological controversy between two views: the first states that odours are perceptually represented as features and the second states that they are represented as objects. In this paper, I aim to systematically address the Bfeature or object^ status of represented odours by concerning whether odours are represented (a) as subjects of properties, (b) as mereological wholes, and (c) entities persisting in a way characteristic for objects. I argue that olfactorily represented odours constitute a sui generis category and cannot be easily classified as objects or features. Such investigations constitute a step in establishing whether various human modalities are unified by organising the environment according to the same categories.

Proceedings of the …, 2007

Frontiers in Psychology, 2013

Human and animal olfactory perception is shaped both by functional demands and by various environmental constraints seemingly peculiar to chemical stimuli. These demands and constraints may have generated a sensory system that is cognitively distinct from the major senses. In this article we identify these various functional demands and constraints, and examine whether they can be used to account for olfaction's unique cognitive features on a case-by-case basis. We then use this as grounds to argue that specific conscious processes do have functional value, a finding that naturally emerges when a comparative approach to consciousness across the senses is adopted. More generally, we conclude that certain peculiar features of olfactory cognition may owe more to limited neocortical processing resources, than they do to the challenges faced by perceiving chemical stimuli.

Frontiers in Human Neuroscience, 2015

What has transpired immediately before has a strong influence on how sensory stimuli are processed and perceived. In particular, temporal context can have contrastive effects, repelling perception away from the interpretation of the context stimulus, and attractive effects (TCEs), whereby perception repeats upon successive presentations of the same stimulus. For decades, scientists have documented contrastive and attractive temporal context effects mostly with simple visual stimuli. But both types of effects also occur in other modalities, e.g., audition and touch, and for stimuli of varying complexity, raising the possibility that context effects reflect general computational principles of sensory systems. Neuroimaging shows that contrastive and attractive context effects arise from neural processes in different areas of the cerebral cortex, suggesting two separate operations with distinct functional roles. Bayesian models can provide a functional account of both context effects, whereby prior experience adjusts sensory systems to optimize perception of future stimuli.

Frontiers in Psychology, 2013

Journal of Theoretical Biology, 2021

Should theories of “higher-level” cognitive effects originate in “lower-level” molecular mechanisms? This paper supports reductionist explanations of sensory perception via molecular mechanisms in neurobiology. It shows that molecular and cellular mechanisms must constitute the material foundation to derive better theories and models for neuroscience. In support of “bottom-up theorizing”, we explore the recent application of a new real-time molecular imaging technique (SCAPE microscopy) to mixture coding in olfaction. Seemingly emergent “higher level” psychological effects in odor perception, irreducible to the physical stimulus, are linked back to underlying molecular mechanisms at the receptor level. Critical to understanding the importance of the SCAPE study is its notable theoretical impact. It proves a possible answer to the neurocomputational challenge in olfaction from combinatorial coding at the periphery: how does the brain discriminate different complex mixtures from widespread and overlapping receptor activation? The failure of previous reductionist structure-odor explanations is shown to reside in misconceptualizations of the critical causal elements involved. Causally fundamental features are not of parts independently of a mechanism. Components and their relevant features are units via their causal role within a mechanism. Here, new technologies allow revisiting our understanding of the ontology and levels of organization of a system.

2020

Topics in Cognitive Science , 2023

Representational drift is a phenomenon of increasing interest in the cognitive and neural sciences. While investigations are ongoing for other sensory cortices, recent research has demonstrated the pervasiveness in which it occurs in the piriform cortex for olfaction. This gradual weakening and shifting of stimulus-responsive cells has critical implications for sensory stimulus-response models and perceptual decision-making. While representational drift may complicate traditional sensory processing models, it could be seen as an advantage in olfaction, as animals live in environments with constantly changing and unpredictable chemical information. Non-topographical encoding in the olfactory system may aid in contextualizing reactions to promiscuous odor stimuli, facilitating adaptive animal behavior and survival. This article suggests that traditional models of stimulus-(neural) response mapping in olfaction may need to be reevaluated and instead motivates the use of dynamical systems theory as a methodology and conceptual framework.

Frontiers in Psychology, 2014

In the present work we present an overview of experimental findings corroborating olfactory imagery observations with the visual and auditory modalities. Overall, the results indicate that imagery of olfactory information share many features with those observed in the primary senses although some major differences are evident. One such difference pertains to the considerable individual differences observed, with the majority being unable to reproduce olfactory information in their mind. Here, we highlight factors that are positively related to an olfactory imagery capacity, such as semantic knowledge, perceptual experience, and olfactory interest that may serve as potential moderators of the large individual variation.

We can learn much about perceptual experience by thinking about how it can mislead us. In this paper, I explore whether, and how, olfactory experience can mislead. I argue that, in the case of olfactory experience, the traditional distinction between illusion and hallucination does not apply. Integral to the traditional distinction is a notion of ‘object-failure’—the failure of an experience to present objects accurately. I argue that there are no such presented objects in olfactory experience. As a result, olfactory experience can only mislead by means of a kind of property hallucination. The implications of my arguments are twofold. First, we see that accounts of representational content cannot always be based on the visual model. And, secondly, we see that we must recast the notion of non-veridicality, allowing for a notion of non-veridical experience that is disengaged from any particular object.

Psychological Review, 2020

The olfactory system represents the most acute and phylogenetically oldest device that the majority of organisms have to know their physical and social environment. In humans, however, the most predominant functional sense is sight, by virtue of an evolutionary path that has strongly limited the role of olfaction in decision making, social behavior, and cognition. The predominance of sight over smell in humans has important neurobiological, behavioral, and cognitive implications, which are discussed here in a comparative perspective. We propose a theoretical framework in which the psychological determinants of olfactory perception-phenomenological aspects, neuropsychological structures, emotional/ affective correlates, cognitive mechanisms, decision-making dynamics, and behavioral outcomes-are coherently connected and integrated. Implications of this theoretical framework for research and for clinical and diagnostic practice are discussed. The olfactory system represents the most acute and phyloge-netically oldest device that the majority of organisms have for knowing their physical and social environment. The main functions of olfaction involve finding food, communicating and behaving socially and sexually, and avoiding predators and other dangers , thus contributing to survival and adaptation to the living environment (Stevenson, 2010). Going up the evolutionary scale, the importance of olfactory perception decreases. In insects, fishes, and numerous mammals, olfaction plays a key role for the survival of the individual and the species; however, in most primates and birds this sense has increasingly weakened and has partially lost its importance. As MacLean (1973) stated, in more evolved mammals, particularly in humans, the evolution of the brain entailed a shift in the relative influence on sexual and social behavior and communication from olfaction to sight. This change implies not only a "dominance" of one sense over another in driving behavior, but also a broader psychological change in humans' relations with their physical and social environment. Naturally, it is not so easy to separate one sense from another in the process through which living organisms gather information from the external world. The perceptive representations of external objects, phenomena, and events usually combine several perceptual modalities, and this multisensory integration is a peculiar neuropsychological and phe-nomenological characteristic of the perceptual process (Spence, 2015). Nevertheless, as MacLean (1973) argued, while the primitive structure of the brain-the limbic system-is functionally guided by olfaction and this determines an olfactory-centric experience of the living environment, the development of the neocortex in some primates entailed a domination of sight over olfaction for experiencing and exploring the external world. According to MacLean (1973), this radical change from the dominance of olfaction to that of sight opens important anthropo-logical, psychological, and neurobiological issues, not yet completely investigated: "The problem before us now is to inquire how the brain gets out from under the domination of the narcissistic, existential olfactory sense to be altruistically guided by the futuristic , visual sense" (p. 43). In this paper, starting from this question, we will deal with the psychological implications of the shift from an olfactory-centric experience in the living environment-still present in the majority of organisms with a nervous system-to a visuo-centric one typical of human beings. To do so, we will (a) provide a theoretical framework to describe the psychological and epistemological features of olfactory perception, making use of the most recent neuroscience; (b) analyze, in a differential perspective, the features of visuo-centric "construction" of the perceived environment by

This paper considers what olfactory experience can tell us about the controversy over qualia and, in particular, the debate that focuses on the alleged transparency of experience. Although some philosophers claim that transparency holds for all of the sense modalities, any detailed discussion of it focuses on vision. But transparency seems unintuitive for olfactory experience. This paper argues that olfactory experience is indeed transparent and that explanations of what transparency is have been obscured by a reliance on the visual model. In this way, the paper clarifies and advances the debate about transparency.

2021

Mention perception, and those with neuroscience training often swiftly turn to sight. Mention studies of perception, and classic Hubel and Wiesel images of oriented bars, concentric receptive fields, or tuning curves may leap forth, framed by eyeballs and an optic chiasm's course toward V1. These images represent cell specificity, hierarchical processing, localization, and, most importantly, an elusive mapping between brain structure and function. And thus, a neuroscientist thinking about perception could well conjure the story that a stable, stereotypic arrangement in the brain can match what is happening in the world. But what about smell? asks A. S. Barwich. What reasons do we have to think that its scientific story is anything like that of vision? Smellosophy begins with appreciation for the dramatic headway made over the past three decades in our scientific understanding of olfaction. The book provides a historical account of the scientific study of smell, noting odor's long resistance to any attempt to probe it. This chronology depicts a rebellious, if powerful, sense: odor failed to fit into traditional schemas of classification, baffled those who tried to understand its flow patterns in the nasal cavity, and fooled scientists into generating tools too simple to capture its existence as a chemical mixture.