Ishan Singhal

How can we investigate non-human experiences scientifically? Given substantial differences in sensory abilities and the private nature of consciousness, this remains an open question. In this review, we propose a way to gain empirical traction on one key feature of experience: its temporal structure, or 'timescape'. Perceptual contents follow systematic temporal principles-synchronisation, revision, and persistence-and are sampled across attentional windows and vary in stability. These principles can be explored through temporal illusions and experimental paradigms. We conceptualise an animal's timescape in terms of five key windows, all of which are experimentally testable, and analyse evidence across animal species to highlight varying timescapes. Together, these ideas lay the foundations for a research programme comparing the temporal Umwelts of non-human animals.

How can we investigate non-human experiences scientifically? Given substantial differences in sensory abilities and the private nature of consciousness, this remains an open question. In this review, we propose a way to gain empirical traction on one key feature of experience: its temporal structure, or 'timescape'. Perceptual contents follow systematic temporal principles-synchronisation, revision, and persistence-and are sampled across attentional windows and vary in stability. These principles can be explored through temporal illusions and experimental paradigms. We conceptualise an animal's timescape in terms of five key windows, all of which are experimentally testable, and analyse evidence across animal species to highlight varying timescapes. Together, these ideas lay the foundations for a research programme comparing the temporal Umwelts of non-human animals.

Integrated information theory of consciousness proposes an identity between its causal structure and phenomenology. Through this assertion, IIT aims to explain consciousness by prioritizing first-person experience. However, despite its phenomenology-first stance, developments in IIT have overlooked temporality. As such, we argue that at present IIT’s phenomenological analysis is incomplete. In this critique, we show how IIT takes a non-identical illusionist stance towards the experiences of continuity, flow, and extent of our experiences. Moreover, in isolating temporal grains of experience to a single timescale, IIT misses out on capturing the multi-scale nested nature of temporal phenomena. Hence, we contend that IIT needs an axiom for time, through which its causal structure can be refined to account for temporal experiences. Here, we propose an axiom to address these concerns. We conclude by discussing how IIT may need to be revised if our concerns hold true.

The way we represent and perceive time has crucial implications for studying temporality in conscious experience. Contrasting positions posit that temporal information is separately abstracted out like any other perceptual property through specialized mechanisms or that time is represented through the temporality of experiences themselves. To add to this debate, we investigate alterations in felt time in conditions where only conscious visual experience is altered through perceptual switches while a bistable figure remains physically unchanged. We predicted that if perceived time is a function of temporally evolving conscious content, then a break in it (here via a perceptual switch) would also lead to a break in felt time. In three experiments, we showed participants a Necker cube that was manipulated to induce a perceptual switch (experiments 1(a) and 1(b)) or left to switch on its own (experiment 2). We asked participants to report both perceptual switches and felt durations (experiments 1(a) and 2) or only estimate time (experiment 1(b)). Over these three experiments, we find evidence of contraction of felt time in trials with a perceptual switch, consistent with the idea that perceived time is a function of temporally evolving conscious experience. Additionally, we present a phenomenological demonstration to support our empirical data. Overall, the study provides evidence for temporal mirroring and isomorphism in visual experience, arguing for a link between the timing of experience and time perception.

This paper explores the use of perhaps the most ubiquitous phrase in time perception literature, i.e., ‘there is no sense organ for time’. I argue here that its usage often highlights several misguided notions about how we perceive time and thus creates a problem in studying it. In this commentary three such underlying notions are discussed which are often drawn as conclusions from the lack of a sensory system to perceive time. These are that time is generated or created separately by the brain, that time perception is different from other kinds of perception and that the study of time is hampered by the lack of a dedicated sense organ. These notions are discussed and argued against. It is claimed that a sense organ for time is not possible, nor does this exclude time from our percepts in general. Moreover, rather than creating a problem, a lack of a sense organ for time offers an opportunity to theorize about our experiences across perceptual modalities and cognitive mechanisms. I conclude by suggesting an end to using this phrase and instead seeing mental time as existing across our experiences.