Neuroscience and Photography
The complex relationship between science and art is especially intriguing in the context of interactions between photography, which occupies a unique technological and cultural niche, and the burgeoning field of neuroscience. Neuroscience is capable of providing valuable insights into the creation and perception of photography and its extant materialities as well as developing entirely new materialities.
I: Neuroscience and the Photographer
From start to finish, photography is based upon perception. First, the photographer must perceive something in their environment that interests them aesthetically. Then, they must manipulate their equipment, usually a camera, to record the incident light reflected from their subjects in a way concordant with their intended depiction of the scene. Later, a viewer will perceive the photograph and experience some thought or sensation. Their physical perception of the scene, and thus their experience of it, will be based upon but altered from the photographer’s original perception of the real environment.
This process is characterized largely by the nature and limits of the human visual system and its distinctions from the mechanical systems of the camera. Therefore, a brief exploration of and comparison between each of these systems and their internal workings is an excellent starting point for developing an understanding of the relationship between neuroscience and photography.
The primary task of the human visual system is to create an ordered representation of three-dimensional space by recording the pattern of light that strikes the retina. It first orients to the middle of the visual field where the fovea produces the sharpest detail. Then, highly specialized ganglion cells begin low-level parsing to process the raw data into information that the brain can use to construct a cohesive scene. One such process is carried out by center-on surround-off cells (Fig. 1), which are maximally activated when struck by light across only a portion of their surface area, and are therefore able to detect edges and lines used to delineate objects (Nelson and Connaughton 1995). Other processes include the detection of shading to estimate shape and the inference of nonexistent visual information in physiologically produced blind spots (Tripathy et al. 1995). Next, the information moves through a complex neural pathway, passing through the lateral geniculate nucleus and eventually arriving at the visual cortex of the parietal lobe. There it undergoes higher-level processing and is given context through communication with the prefrontal cortex (Nelson and Connaughton 1995).
These layers of processing have evolved for maximal efficiency, filtering out any extraneous information and retaining only that which is necessary for improving chances of survival. In contrast, the mechanical systems of the camera directly record unaltered patterns of light without any parsing or application of visual heuristics. In this sense, the camera has a more objective view of the world. As a result, it becomes the challenge and opportunity of the photographer to recreate and manipulate the missing quirks of human sight. For example, the human visual system calculates depth by analyzing the adjustment of focal muscles and disparities between the images projected onto each retina (Braunstein et al. 2014; Rolland et al. 1995). Since most photographs lack binocularity, a photographer may choose to rely upon the use of a large, shallow aperture to simulate a particular squeezing of the focal muscles and generate an illusory sensation of depth (Watt et al. 2005). The visual system also corrects for other challenges imposed by our sensory organs. The curvature of our eyes, which are equivalent in focal length to an ultra-wide 17mm lens, produces significant barrel distortion (Fig. 2) that the brain automatically straightens out to generate a 43mm-equivalent image in our attentional field (Cameron et al. 1999). The photographer using a similarly wide lens may choose to mimic this correction through digital alteration, or they may forgo it for their own artistic purposes. We experience blur while tracking rapid movement because as a stimulus moves across our visual field with sufficient speed, it activates groups of retinal cells before adjacent groups have had time to return to their base firing rate. As a result, we perceive the subject to occupy multiple positions at once. The photographer can eliminate or accentuate this effect by varying their shutter speed.
Beyond simply mimicking artifacts of the human visual system, the photographer may also choose to provoke or trick it into certain responses. Because the real world provides three-dimensional resolution and information far beyond the absorptive capacity of our brains and two-dimensional retinal planes, a single pattern of incident light that we perceive may result from many different arrangements of the real world (Carbon 2014). The human visual system has accordingly evolved to accept what it determines as the most likely possibility. In the real world, variables like binocular comparison and the movement of the viewer relative to the subject help to ensure accuracy, but two-dimensional photographs with their relative scarcity of information can often fool the brain. This produces among other phenomena forced-perspective optical illusions like the much-duplicated “leaning against the Tower of Pisa” or “people in hand” (Fig. 3A & B). In a more general sense, these quantitative limitations of the visual system also emphasize the significance of the photographer’s role in composing the scene and selecting stimuli to present. Studies show that objects in the visual field that are irrelevant to an implied task can be actively obscured by the brain, so the photographer should consider carefully the thoughts and emotions that they provoke in their viewers, as these may determine the ability to perceive visual elements (Most et al. 2005).
II: Agnosias and Objects
As an organic system, human visual processes are subject to unique malfunctions. Of course, blindness or impairment may be induced by damage to the physical eye and its components. Breakdown of neural circuitry responsible for the processing of visual information is also possible. This condition, called visual agnosia, may take many forms including akinetopsia (the inability to perceive movement), cerebral achromatopsia (difficulty in recognizing and categorizing colors), and hemispatial neglect (inability to attend to stimuli in half of the visual field). Among the simplest visual agnosias is the inability to recognize objects and scenes, which is divided into two categories: apperceptive and associative. In apperceptive agnosias, patients are completely unable to distinguish shapes and have trouble recognizing or copying different visual stimuli. In associative agnosias, patients can describe and copy stimuli but still fail to recognize them, for example knowing that a fork is a related to eating in some way but being unable to name it specifically (Riddoch and Humphreys 2003). These conditions are particularly interesting with respect to our discussion of neuroscience and photography because they offer exceptional insights into the way the brain perceives photographs.
In general, findings from clinical neuroscience support the perspective that photographs are unique traces that represent, but do not equal, their subjects. Hiraoka et al. (2009), for example, showed that patients with associative agnosias are significantly better at identifying objects from photographs than from line drawings. This is corroborated by the work of Humphrey et al. (1994), which additionally suggested that such patients can more quickly and accurately identify objects from color photographs than black-and-white ones. Chainay and Humphreys (2001) also found similar results, and introduced an additional comparison to real-world objects. In this regard, they determined that even black-and-white photographs could be equally recognizable as real objects when the viewer’s head was fixed in place, but that when the viewer was allowed to move about and take advantage of stereopsis, objects became more easily recognizable. These results are supported by case studies including Young and Ellis (1989) and Jankowiak et al. (1992) as well as group experiments like Davidoff and De Bleser (1994) and De Renzi et al. (1991). Notably, they hold for both apperceptive and associate agnosias, indicating that the experience of perceiving photographs is distinct from that of either objects or drawings at both lower and higher levels of visual processing. Prior to the advent of such neuroscientific studies, efforts to compare the perception of various mediums of art and object representation were largely the domain of philosophical art theory like that of Currie (1991). While these new techniques are unlikely to replace such qualitative methods entirely, they certainly contribute a valuable perspective relatively uncolored by any existing dogma.
Other types of neuroscientific research have also contributed to the current understanding of the perceptual distinction between objects and photographs. Snow et al. (2014), working with neurologically healthy patients, demonstrated that (similarly to the agnosia studies) photographs are generally more memorable than drawings but less so than physical objects (Fig. 4). Bushong et al. (2010) conducted another behavioral experiment in which they found that the value assigned to objects is affected by the format in which they are viewed. After giving students a small sum of money that could be used to purchase a variety of test objects, they depicted the items as either text displays, high-resolution images, or actual real-world objects. Students were willing to pay 40-61% more for objects they viewed as physical objects over the same items depicted as text or images. Interestingly, this effect disappeared when the objects were placed behind a transparent barrier, suggesting that it was based on the potential for interaction. Both Snow and Bushong’s experiments support the findings of Chainay and Humphreys (2001) above, which might lead one to the conclusion that physical objects are fundamentally more engaging than photographs. However, such an inference cannot be made without reservations: brain-scanning studies, including Snow et al. (2011) found that 2D images elicited “greater overall activation of visual processing areas in the lateral occipital cortex and posterior fusiform gyrus” as compared to 3D objects. One hypothesized explanation for this counterintuitive effect is the presence of inherent perceptual contradictions in the photographic medium. In the spirit of their more abstract dualities (e.g. temporality and timelessness, uniqueness and replicability, objectivity and falsehood, etc.), photographs also present a dichotomous set of stimuli to the visual system and brain. While shading, focal plane, and subject texture can indicate depth and physicality, binocular vision, details of the paper and ink, and size often remind viewers of the flatly representative nature of the photograph. Attempting to reconcile these discordant data points, the brain and visual cortex exhibit an elevated burst of activity. Viewing a physical object, on the other hand, presents information that is generally consistent with a single logical interpretation of the scene – a comparatively easy cognitive task. In the context of the photographic discipline, this suggests counterintuitively that a photograph of a scene may be more visually engaging in some ways than the scene itself – an interesting idea in relation to the long periods of time spent absorbing fine art photographs, especially those imbued with particular aura.
III: Dematerialization and Material Qualities
Though the neuroscientific differences between traditional photographs and objects are significant, it is worth noting that both have corporeal form. Neuroscience can also inform an understanding of the virtual manifestations of photography that have become commonplace over the last couple of decades. One study examining the relative effectiveness of print and digital photograph-based advertisements concluded that, on average, people attend to digital photographs for longer due to an increased cognitive load of the type discussed above, but that unaided brand recall and “motivation to act” are significantly higher for print advertisements (“A Bias for Action” 2015). Another used an fMRI machine to find that viewing print advertisements produced greater activation of the ventral striatum, an area known for predicting consumer behavior with more accuracy than self-reported preferences (Venkatraman et al. 2015). A third showed widespread differences in the parts of the brain activated by each medium, with print producing greater stimulation of everything from spatial representation to emotional response strength (Fig. 5, Millward Brown 2009). These findings suggest that, though digital photographs are increasingly more common in our everyday lives and demand more of our attention, print images have certain unique attributes which can influence our behavior and patterns of cognition more deeply than their virtual counterparts. While this may be true, a closer look at these purportedly independent studies reveals that all three were funded by major mail agencies (the Canadian, British, and US Post Services, respectively) in the last few years – a time period during which the already-threatened print advertisement industry has experienced an annual decrease in revenue of 10% or more (Vranica and Marshall 2016). Additionally, none of the three reports appear to be peer-reviewed or published in an actual neuroscientific journal, casting further doubt upon their credibility. In evaluating such results, it is imperative to keep in mind that photography, besides an academic and artistic pursuit, is also a commercial technology that can be subject to influence by corporate interests.
Extant research on the perception of material qualities in print photographs, an area perhaps less directly influenced by market forces, appears to be more reputable. It is intuitively clear that photographic paper metrics such as texture, size, and gloss influence aesthetic perception, and extensive studies have been made of trends in these metrics based on time, space, and the choices of artists (Messier 2011). Scientific information regarding the perception of these qualities is also available, though less centralized. One study of the physiology of touch, for instance, found multiple distinct biomechanical pathways for the sensation of texture depending on whether the texture interval was greater or less than approximately 200 m (Hollins, Bensmaïa, and Sliman 2007) . The same study also determined that the subjectively assigned degree of roughness was a logarithmic function of actual physical roughness based on the maximum vibrational frequency allowed by the speed of digit movement and characteristics of the paper’s texture pattern. Chu et al. (2013) analyzed the effects of photograph size on aesthetic perception and found various effects based on the image content, also revealing that a change in physical size was significantly more influential on preference than a change in resolution, even when both changes were calibrated to yield similar levels of overall photographic detail. Fleming (2014) demonstrated that rather than estimating physical specular properties of the material itself as was previously hypothesized, the visual system interprets gloss by constructing a statistical model of visual qualities like highlights and calculating deviance from the mean, implying that this model can be manipulated by displaying a photograph near other photos or surfaces of particular gloss levels. Gershoni and Kobayashi (2005), turning their attention specifically towards material photography, measured variance in visual fixation patterns, preference, and contrast detection between slightly different prints of Ansel Adams photos (Fig. 6). Their experiment elucidated, among other things, differences in the way that amateurs and experts look at photographs. The results of such studies can sometimes seem esoteric or of limited practicality, but collectively form a robust model of neuroaesthetic perception that can be improved and applied to various disciplines over time.
IV: Photographers and New Photographic Materialities
Though some of these principles have only recently been scientifically investigated, the work of many photographers displays an implicit familiarity with them. Scandinavian photographers Inka and Niclas Lindergård (2016), for instance, recently displayed their series The Belt of Venus and the Shadow of the Earth by printing each piece directly onto a rock of specific size and shape (Fig. 7A, B, C). As discussed above, attention times are generally longer for photographs than physical objects due to the increased complexity of perception. Therefore, in converting their scenes from physical objects to photographs and back again, the Lindergårds introduced yet another layer of cognitive load and enabled their work to approach the visual system from multiple perceptual pathways simultaneously. In a similar vein, their series Vista Points obscures the center of famous American landscapes with a large dark circle produced by a quarter from a set of tourist binoculars, thereby eliminating the area of the visual field in front of the fovea that is usually sharpest. By removing chunks from the outlines of well-known features like El Capitan, they activate patterning circuitry driven by retinal ganglion cells and encourage the viewer’s brain to fill in the gaps with implied – but absent – shapes. Others like Elena Dorfman and David Hockney, as explained by Keats (2015), seek to reintroduce the ambiguities of human perception into their photographs through digital manipulation, crafting overlaid Impressionist and Cubist collages more reminiscent of the dynamic saccades of organic vision than the relative objectivity of traditional photography (Fig. 8).
Beyond providing insights into the processes of creating and experiencing photographs, modern neuroscience has also begun to create entirely new photographic materialities. These can replace impaired capabilities, as in the case of colorblind artist Neil Harbisson, who designed a specialized camera that protrudes antenna-like from his head and feeds color data to a chip implanted in his skull to produce pitched vibrations corresponding to the particular hues of the scene before him (Fig. 9). Harbisson says that after using the device for a number of years, he’s even begun to dream in his new form of color. He is already able to experience colors wirelessly from photos on his phone and has expressed his belief that, if another person were to wear a similar device, they could transmit such experiences directly to one another (Harbisson 2012). These materialities can also extend the experience of photography to the totally blind, who have historically been mostly unable to interact meaningfully with photography. For instance, Erik Weihenmayer (the first blind man to summit Everest) is able to do everything from playing tic-tac-toe with his daughter to tackling challenging rock climbs in Utah and Colorado thanks to a device designed by neuroscientist Paul Bach-y-Rita that conducts patterns of electrical impulses from a head-mounted camera to the surface of his tongue (Fig. 10, Twilley 2017).
While remapping sensory modalities in this way is a perfectly viable approach to vision, cutting-edge technology can even go so far as to begin to replace it directly. The Argus II retina prosthesis, developed by Second Sight, transmits information from an external camera to electrodes wired into visual system neurons and is capable of reproducing basic images in a low-resolution grayscale grid, such that some blind patients can identify large block letters or basic household items. Other groups are also working on similar devices, such as the German company Retina Implant, which recently completed human testing for an entirely self-contained device that uses photosensitive diodes to reproduce 1,500-pixel vision without any externally visible equipment (Fig. 11). These technologies are still in their infancy – Retina Implant’s device enabled only three out of nine subjects to read letters – but represent a major step forward in human perception and an entirely novel materiality for photography. In a sense, after all the intervening years of mediation by film and digital cameras, a light-sensitive chip embedded in the eye represents a return to the original form of photography as the unadulterated impact of light to create physical sensory impressions – unique traces of specific moments in space and time. Such innovations and the growing relationship between photography and neuroscience will undoubtedly continue to enrich both fields in the years ahead.
Figures:
Figure 1: Left: The center-surround receptive fields of the ganglion cells in the retina with an excitatory center and inhibitory surround. Right: The response of such a ganglion cell to a spot of light increasing in diameter.
Aditi, Majumder. “The Visual System.” Cognitive Psychology, 2005, pp. 1–7, doi:10.1037/a0027822.
Figure 2: Barrel distortion of the type produced by the human eye.
“Camera Matching.” The Foundry, 2017, https://help.thefoundry.co.uk/modo/content/help/pages/rendering/camera_matching.html.
Figure 4: Recall task performance for various depictions of objects.
Snow, Jacqueline C, Rafal M Skiba, Taylor L Coleman, and Marian E Berryhill. 2014. “Real-World Objects Are More Memorable than Photographs of Objects.” Frontiers in Human Neuroscience 8. Frontiers Media SA:837.
Figure 5: Areas of brain activity as measured by oxygenated
blood flow for physical (red) and digital (blue) ads.
Millward Brown. 2009. “Using Neuroscience to Understand the Role of Direct Mail.” Millward Brown, 3.
Figure 6: Fixation centers (as measured by eye-tracking devices)
in various prints of the same Ansel Adams photograph
Gershoni, S, and H Kobayashi. 2005. “How We Look at Photographs-as Indicated by Contrast Detection, Preference and Eye-Movement Patterns.” International Conference on Digital Printing Technologies, Final Program and Proceedings, 124–25.
Figure 8: Self Portrait, a photographic “joiner” collage by David Hockney
Figure 9: Neil Harbisson with his color-sensing device.
https://upload.wikimedia.org/wikipedia/commons/7/77/Neil_Harbisson_cyborgist.jpg
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(Hiraoka et al. 2009) Humphrey chainay and Humphreys young hank Davidoff de renzi currie snow x2 bushong chu fleming gershoni keats(Chainay and Humphreys 2001; Young and Ellis 1989; Jankowiak et al. 1992; Davidoff and De Bleser 1994; De Renzi et al. 1991; Currie 1991; Snow et al. 2011, 2014)(Bushong et al. 2010; Chu, Chen, and Chen 2013; Fleming 2012; Gershoni and Kobayashi 2005)(Keats 2015)(Humphrey et al. 1994)