On the Spatiotemporal Nature of Vision, as Revealed by Covered Bridges and Puddles: A Dispatch from Vermont

Retinal painting, anorthoscopic perception and amodal completion are terms to describe visual phenomena that highlight the spatiotemporal integrative mechanisms that underlie primate vision. Although commonly studied using simplified lab-friendly stimuli presented on a computer screen, this is a report of observations made in a novel real-world context that highlight the rich contributions the mechanisms underlying these phenomena make to naturalistic vision.

Do We Visually Experience Objects’ Occluded Parts?

A number of philosophers have held that we visually experience objects’ occluded parts, such as the out-of-view exterior of a voluminous, opaque object. That idea is supposed to be what best explains the fact that we see objects as whole or complete despite having only a part of them in view at any given moment. Yet, the claim doesn’t express a phenomenological datum and the reasons for thinking we do experience objects’ occluded parts, I argue, aren’t compelling. Additionally, I anticipate and reply to attempts to salvage the idea by appeal to perceptual expectation and amodal completion. Lastly, I address potential concerns that the only way to capture the phenomenal character of perceiving voluminous objects is to say experience outstrips what’s in view, providing a description of such experience without any implication of that idea.

Grief’s impact on sensorimotor expectations: an account of non-veridical bereavement experiences

The philosophy of grief has directed little attention to bereavement’s impact on perceptual experience. However, misperceptions, hallucinations and other anomalous experiences are strikingly common following the death of a loved one. Such experiences range from misperceiving a stranger to be the deceased, to phantom sights, sounds and smells, to nebulous quasi-sensory experiences of the loved one’s presence. This paper draws upon the enactive sensorimotor theory of perception to offer a phenomenologically sensitive and empirically informed account of these experiences. It argues that they can be understood as deriving from disruption to both sensorimotor expectations and perceived opportunities for action, stemming from the upheaval of bereavement. Different facets of the enactive sensorimotor approach can help to explain different types of post-bereavement perceptual experience. Post-bereavement misperceptions can be accounted for through the way that alterations to sensorimotor expectations can result in atypical ‘amodal completion’, while bereavement hallucinations can be understood as ‘appearances’ that fail to form part of the usual patterns of sensorimotor contingency. Quasi-sensory experiences of the presence of the deceased can be understood as resulting from changes to perceived affordances. This paper aims to demonstrate the explanatory value of key aspects of the sensorimotor approach by highlighting how they can help to explain the phenomenology of post-bereavement experiences. However, it also illuminates certain areas in which the sensorimotor approach ought to be supplemented, especially if it is to account for tight connections between perception, affect, and intersubjectivity that are salient in grief.

What do we see behind an occluder? Amodal completion of statistical properties in complex objects

When a spiky object is occluded, we have the compelling percept that its spiky features continue behind the occluder. Although many real-world objects contain complex features, it is unclear how their features are amodally completed and whether this process is automatic. To this end, we asked participants to search for oddball targets among distractors and asked whether similarity relations in visual search between occluded displays match better with global or local completions of these displays. In Experiment 1, when objects with curved/straight corners were occluded, they were perceived as continuing with the same features than with them exchanged. In Experiment 2, we obtained similar results for objects with irregular/symmetric features. Analogous investigations on deep neural networks revealed similar results for curved/straight contours but not for irregular/symmetric features. Thus, amodal completion involves extending not only simple contours, but also their more global statistical properties.

Is Perception Stimulus-Dependent?

The most natural way to distinguish perception from cognition is by considering perception as stimulus-dependent. Perception is tethered to the senses in a way that cognition is not. Beck Australasian Journal of Philosophy 96(2): 319-334 (2018) has recently argued in this direction. He develops this idea by accommodating two potential counterexamples to his account: hallucinations and demonstrative thoughts. In this paper, I examine this view. First, I detect two general problems with movement to accommodate these awkward cases. Subsequently, I place two very common mental phenomena under the prism of the stimulus-dependence criterion: amodal completion and visual categorization. The result is that the stimulus-dependent criterion is too restrictive, it leaves the notion of perception extremely cramped. I conclude that even the criterion of stimulus-dependence fails to mark a clearly defined border between perception and cognition.