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91��ɫ Research Chair, philosopher and core member of VISTA adds new insights on the question of what constitutes reality. Jacob Beck unpacks key philosophical questions around mental representation, mental imagery, and consciousness.

How do we know what’s real? Simply put, we see it, and know it to be real. But sometimes we see it in our mind’s eye. Mental representation, or mental imagery, in the philosophy of the mind is an internal cognitive symbol that represents external reality. This way, we can easily recall what a car, apple, rabbit or book look like. Mental imagery can also visualize things that don’t exist, like a third arm.

Liberal Arts & Professional Studies Professor Jacob Beck, a 91��ɫ Research Chair in the Philosophy of Visual Perception and a core member of both the Vision: Science to Applications (VISTA) program and the Centre for Vision Research, has made it his life’s work to investigate this further. His highly compelling research takes a deep dive into long-standing philosophical puzzles about mental representation and consciousness.

In 2018, with funding from the Social Sciences & Humanities Research Council of Canada and VISTA, Beck produced a seminal article, “Analog mental representation,” published in the Wiley journal WIREs Cognitive Science. This was a literature review that summed up the findings of existing thought in this key area. Importantly, he drew from both philosophy and psychology.

“Over the past half century, philosophers and psychologists have argued for the existence of analog mental representations of one type or another,” he explains. “This study reviews the arguments around three types of analog mental representation. It is my hope that this will open avenues for future research.”

“Why should we care if mental representations are analog?”

To understand Beck’s research paper, it’s important to first understand the meaning of analog. This is an adjective that describes the format in which information is coded. For example, most regular alarm clocks code the time of day digitally. By contrast, a wall clock with a circular face and hour and minute hands uses an analog code. Could the brain likewise code some information in an analog fashion? This is at the heart of Beck’s inquiry.

In this study, Beck focuses on the analog and investigates three different mental representations: perceptual, imagery and numerosity (or countable) representation.

Beck provides two compelling answers as to why we should care if mental representations are analog:

1. To better understand how brains compute: “For purposes of reverse engineering actual minds, getting the format of mental representations right will assist in discovering many of the representations’ other properties. Whether minds are analog will therefore influence our understanding of how they compute,” he says.
2. To better understand states of mind: “Philosophers have often hypothesized about different kinds of mental states, such as perception and thought. Knowing which mental states are analog should be useful for formulating these hypotheses,” he states.

Case one: Philosophers’ work on perception

Beck sums up the work of several philosophers – notably, British scholar Gareth Evans and Columbia University’s Christopher Peacocke in the 1980s and 1990s. Evans observed that our visual experiences of colour are fine-grained. For example, we can see many different shades of red, from crimson to scarlet.

Peacocke added to this idea by observing that other perceptible things, such as distance, size and orientation, can be discriminated in perception. Peacocke goes on to suggest that perception is “unit free,” meaning we perceive distance not necessarily in terms of inches or feet. The scientific community, Beck notes, is not in universal agreement on this idea.

Case two: Psychologists’ work on imagery

Here, Beck explains the contribution of two Stanford University psychologists, Roger Shepard and Jacqueline Metzler (1971), in the areas of mental rotation and mental scanning. He describes two classic studies that claimed to prove that mental representations underlying imagery are analog.

In the mental rotation study, the researchers showed subjects a pair of three-dimensional shapes and asked them to determine, as quickly as possible, whether they were the same or different.

They found that the subjects’ reaction times were related to the degree to which the shapes were out of rotation. In other words, the more out of rotation they were, the more time it took the subjects to realize and answer that they were the same.

Most researchers conclude that this experiment proved that the subjects mentally rotate image-like representations of the shapes in their heads. However, this interpretation of the findings is controversial.

Case three: Psychologists’ work on numerosity

Numerosity, or the ability to be counted, is also examined in Beck’s article. Humans can understand numerosity. For example, if you are presented with two clusters of dots on a screen, even when you can’t count them due to a lack of time, you can still reliably determine which cluster has more dots.

However, this changes based on the ratio. If one cluster has 35 dots and another has 40 dots, you are more likely to successfully determine that the second cluster has more dots than you would be if the two clusters had 40 and 45 dots, respectively. (Beck goes on to discuss a few theories that explain this phenomenon – continuous magnitudes, the picture principle and covariation.)

Presses for clarity and cohesion in future research

Beck underscores two key areas for future investigations. First, he proposes an improved alignment between philosophy and psychology. “There’s room to bring psychological research more directly to bear on whether perception is analog,” he explains.

Second, he presses for a universal understanding of analog representation. “This is one place where further philosophical work would be helpful,” he states.

To read the full article, visit the . To read more about Beck’s work, visit his or his .

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By Megan Mueller, senior manager, research communications, Office of the Vice-President Research & Innovation, 91��ɫ, muellerm@yorku.ca