Jake Quilty-Dunn

Logical reasoning is one of humanity's most powerful abilities. A widespread assumption across psychology, linguistics, and philosophy holds that reasoning operates over concepts that refer to objects and properties in the world, yet this has rarely been tested empirically. We introduce a novel paradigm that exploits lexical ambiguity to differentiate candidate representations for human inference: word-forms, reference-fixing concepts, or more abstract "underspecified representations" that constrain meaning without fully determining it. Across three experiments (N=158), participants evaluated deductive arguments equivocating over polysemous or homonymous terms. Although these arguments are logically equivalent under standard analyses, participants reliably accepted non-truth-preserving polysemous arguments while rejecting homonymous ones. This asymmetry—the Uncommon Sense Effect—points to underspecified representations as the default basis of logical inference. This challenges a foundational assumption about meaning, and opens new empirical avenues for studying the link between what we think and why we think it.

Mental representations remain the central posits of psychology after many decades of scrutiny. However, there is no consensus about the representational format(s) of biological cognition. This paper provides a survey of evidence from computational cognitive psychology, perceptual psychology, developmental psychology, comparative psychology, and social psychology, and concludes that one type of format that routinely crops up is the language-of-thought (LoT). We outline six core properties of LoTs: (i) discrete constituents; (ii) role-filler independence; (iii) predicate–argument structure; (iv) logical operators; (v) inferential promiscuity; and (vi) abstract content. These properties cluster together throughout cognitive science. Bayesian computational modeling, compositional features of object perception, complex infant and animal reasoning, and automatic, intuitive cognition in adults all implicate LoT-like structures. Instead of regarding LoT as a relic of the previous century, researchers in cognitive science and philosophy-of-mind must take seriously the explanatory breadth of LoT-based architectures. We grant that the mind may harbor many formats and architectures, including iconic and associative structures as well as deep-neural-network-like architectures. However, as computational/representational approaches to the mind continue to advance, classical compositional symbolic structures – that is, LoTs – only prove more flexible and well-supported over time.

“What is the structure of thought?” is as central a question as any in cognitive science. A classic answer to this question has appealed to a Language of Thought (LoT). We point to emerging research from disparate branches of the field that supports the LoT hypothesis, but also uncovers diversity in LoTs across cognitive systems, stages of development, and species. Our letter formulates open research questions for cognitive science concerning the varieties of rules and representations that underwrite various LoT-based systems and how these variations can help researchers taxonomize cognitive systems

Most theories of concepts take concepts to be structured bodies of information used in categorization and inference. This paper argues for a version of atomism, on which concepts are unstructured symbols. However, traditional Fodorian atomism is falsified by polysemy and fails to provide an account of how concepts figure in cognition. This paper argues that concepts are generative pointers, that is, unstructured symbols that point to memory locations where cognitively useful bodies of information are stored and can be deployed to resolve polysemy. The notion of generative pointers allows for unresolved ambiguity in thought and provides a basis for conceptual engineering.

Ensemble perception—the encoding of objects by their group properties—is known to be resistant to outlier noise. However, this resistance is somewhat paradoxical: how can the visual system determine which stimuli are outliers without already having derived statistical properties of the ensemble? A simple solution would be that ensemble perception is not a simple, one-step process; instead, outliers are detected through iterative computations that identify items with high deviance from the mean and reduce their weight in the representation over time. Here we tested this hypothesis. In Experiment 1, we found evidence that outliers are discounted from mean orientation judgments, extending previous results from ensemble face perception. In Experiment 2, we tested the timing of outlier rejection by having participants perform speeded judgments of sets with or without outliers. We observed significant increases in reaction time (RT) when outliers were present, but a decrease compared to no-outlier sets of matched range suggesting that range alone did not drive RTs. In Experiment 3 we tested the timing by which outlier noise reduces over time. We presented sets for variable exposure durations and found that noise decreases linearly over time. Altogether these results suggest that ensemble representations are optimized through iterative computations aimed at reducing noise. The finding that ensemble perception is an iterative process provides a useful framework for understanding contextual effects on ensemble perception.

Many contemporary epistemologists take rational inference to be a conscious action performed by the thinker (Boghossian 2014; 2018; Valaris 2014; Malmgren 2018). It is tempting to think that rational evaluability requires responsibility, which in turn requires conscious action. In that case, unconscious cognition involves merely associative or otherwise arational processing. This paper argues instead for deep rationalism: unconscious inference often exhibits the same rational status and richly structured logical character as conscious inference. The central case study is rationalization, in which people shift their attitudes in logically structured, reason-responsive ways in response to evidence of their own incompetence or immorality. These attitude shifts are irrational in a way that reflects on the thinker. Thus rationally evaluable inference extends downward into the unconscious. Many take the sole aim of belief to be truth (Velleman 2000) or knowledge (Williamson 2000), but the prevalence of rationalization suggests that belief updating often aims instead at preserving our positive conceptions of ourselves—that is, belief updating is part of a psychological immune system (Gilbert 2006; Mandelbaum 2019). This paper argues that the psychological immune system comprises a suite of distinct cognitive mechanisms, some (ir)rational and some arational, which are united by a common function of avoiding the maladaptive predomination of negative affect and maintaining stable motivation. Other aspects of the psychological immune system include (i) a domain-general positive bias in evaluative attitudes and (ii) “terror management,” i.e., the systematic strengthening of meaning-conferring beliefs to avoid death anxiety. The multiplicity of processes underlying the psychological immune system point toward an irrational but adaptive function of cognition to keep us motivated in a world rife with negativity and death.

According to a classic but nowadays discarded philosophical theory, perceptual experience is a complex of nonconceptual sensory states and full-blown propositional beliefs. This classical dual-component theory of experience is often taken to be obsolete. In particular, there seem to be cases in which perceptual experience and belief conflict: cases of known illusions, wherein subjects have beliefs contrary to the contents of their experiences. Modern dual-component theories reject the belief requirement and instead hold that perceptual experience is a complex of nonconceptual sensory states and some other sort of conceptual state. The most popular modern dual-component theory appeals to sui generis propositional attitudes called ‘perceptual seemings’. This article argues that the classical dual-component theory has the resources to explain known illusions without giving up the claim that the conceptual components of experience are beliefs. The classical dual-component view, though often viewed as outdated and implausible, should be regarded as a serious contender in contemporary debates about the nature of perceptual experience.

According to one important proposal, the difference between perception and cognition consists in the representational formats used in the two systems (Carey, 2009; Burge, 2010; Block, 2014). In particular, it is claimed that perceptual representations are iconic, or image-like, while cognitive representations are discursive, or language-like. Taking object perception as a test case, this paper argues on empirical grounds that it requires discursive label-like representations. These representations segment the perceptual field, continuously pick out objects despite changes in their features, and abstractly represent high-level features, none of which appears possible for purely iconic representations.

The notion of an object file figures prominently in recent work in philosophy and cognitive science. Object files play a role in theories of singular reference, object individuation, perceptual memory, and the development of cognitive capacities. However, the philosophical literature lacks a detailed, empirically informed theory of object files. In this paper, we articulate and defend the multiple-slots view, which specifies both the format and architecture of object files. We argue that object files represent in a non-iconic, propositional format that incorporates discrete symbols for separate features. Moreover, we argue that features of separate categories are stored in separate memory slots within an object file. We supplement this view with a computational framework that characterizes how information about objects is stored and retrieved.

Perceptual experiences justify beliefs. A perceptual experience of a dog justifies the belief that there is a dog present. But there is much evidence that perceptual states can occur without being conscious, as in experiments involving masked priming. Do unconscious perceptual states provide justification as well? The answer depends on one’s theory of justification. While most varieties of externalism seem compatible with unconscious perceptual justification, several theories have recently afforded to consciousness a special role in perceptual justification. We argue that such views face a dilemma: either consciousness should be understood in functionalist terms, in which case our best current theories of consciousness do not seem to imbue consciousness with any special epistemic features, or it should not, in which case it is mysterious why only conscious states are justificatory. We conclude that unconscious perceptual justification is quite plausible.

Reid endorsed a doxastic theory of perception, on which beliefs are constituents of perceptual experiences. This theory faces the problem of known illusions: we can perceive that p while believing that not-p. Some scholars argue that the problem of known illusions and other problems entail that Reid’s view cannot be charitably interpreted as a doxastic theory. This paper explores Reid’s theoretical commitments with respect to belief acquisition and uses textual evidence to show that his theory is genuinely doxastic. It then argues that a Reidian response to the problem of known illusions can be formulated by appeal to the thesis that perceptual beliefs are formed noninferentially. Reid can also resist the intuition that we lack illusory beliefs in known-illusion cases given his independent reasons for doubting our capacity to identify perceptual beliefs by introspection. The paper then surveys other problems raised in the secondary literature and argues that none decisively undermine the doxastic interpretation of Reid.

It is an orthodoxy in cognitive science that perception can occur unconsciously. Recently, Hakwan Lau, Megan Peters and Ian Phillips have argued that this orthodoxy may be mistaken. They argue that many purported cases of unconscious perception fail to rule out low degrees of conscious awareness while others fail to establish genuine perception. This paper presents a case of unconscious perception that avoids these problems. It also advances a general principle of ‘phenomenal coherence’ that can insulate some forms of evidence for unconscious perception from the methodological critiques of Lau, Peters and Phillips.

Perceptual systems respond to proximal stimuli by forming mental representations of distal stimuli. A central goal for the philosophy of perception is to characterize the representations delivered by perceptual systems. It may be that all perceptual representations are in some way proprietarily perceptual and differ from the representational format of thought (Dretske 1981; Carey 2009; Burge 2010; Block ms.). Or it may instead be that perception and cognition always trade in the same code (Prinz 2002; Pylyshyn 2003). This paper rejects both approaches in favor of perceptual pluralism, the thesis that perception delivers a multiplicity of representational formats, some proprietary and some shared with cognition. The argument for perceptual pluralism marshals a wide array of empirical evidence in favor of iconic (i.e., image-like, analog) representations in perception as well as discursive (i.e., language-like, digital) perceptual object representations.

The question of whether perception is encapsulated from cognition has been a major topic in the study of perception in the past decade. One locus of debate concerns the role of attention. Some theorists argue that attention is a vehicle for widespread violations of encapsulation; others argue that certain forms of cognitively driven attention are compatible with encapsulation, especially if attention only modulates inputs. This paper argues for an extreme thesis: no effect of attention, whether on the inputs to perception or on perceptual processing itself, constitutes a violation of the encapsulation of perception.

Short‐term memory in vision is typically thought to divide into at least two memory stores: a short, fragile, high‐capacity store known as iconic memory, and a longer, durable, capacity‐limited store known as visual working memory (VWM). This paper argues that iconic memory stores icons, i.e., image‐like perceptual representations. The iconicity of iconic memory has significant consequences for understanding consciousness, nonconceptual content, and the perception–cognition border. Steven Gross and Jonathan Flombaum have recently challenged the division between iconic memory and VWM by arguing against the idea of capacity limits in favor of a flexible resource‐based model of short‐term memory. I argue that, while VWM capacity is probably governed by flexible resources rather than a sharp limit, the two memory stores should still be distinguished by their representational formats. Iconic memory stores icons, while VWM stores discursive (i.e., language‐like) representations. I conclude by arguing that this format‐based distinction between memory stores entails that prominent views about consciousness and the perception–cognition border will likely have to be revised.

ABSTRACTThis paper provides a naturalistic account of inference. We posit that the core of inference is constituted by bare inferential transitions, transitions between discursive mental representations guided by rules built into the architecture of cognitive systems. In further developing the concept of BITs, we provide an account of what Boghossian [2014] calls ‘taking’—that is, the appreciation of the rule that guides an inferential transition. We argue that BITs are sufficient for implicit taking, and then, to analyse explicit taking, we posit rich inferential transitions, which are transitions that the subject is disposed to endorse.

Unconscious logical inference seems to rely on the syntactic structures of mental representations (Quilty-Dunn & Mandelbaum 2018). Other transitions, such as transitions using iconic representations and associative transitions, are harder to assimilate to syntax-based theories. Here we tackle these difficulties head on in the interest of a fuller taxonomy of mental transitions. Along the way we discuss how icons can be compositional without having constituent structure, and expand and defend the “symmetry condition” on Associationism (the idea that associative links and transitions are perfectly symmetric). In the end, we show how a BIT (“bare inferential transition”) theory can cohabitate with these other non-inferential mental transitions.

Dispositionalism about belief has had a recent resurgence. In this paper we critically evaluate a popular dispositionalist program pursued by Eric Schwitzgebel. Then we present an alternative: a psychofunctional, representational theory of belief. This theory of belief has two main pillars: that beliefs are relations to structured mental representations, and that the relations are determined by the generalizations under which beliefs are acquired, stored, and changed. We end by describing some of the generalizations regarding belief acquisition, storage, and change.