The Echoes of the Mind – Categorization


“An endless task, the cataloguing of reality. We accumulate facts, we discuss them, but with every line that is written, with every statement that is made, one has the feeling of incompleteness.” ~ Martinique psychiatrist Frantz Fanon

The mind’s most basic function is pattern-matching. Its polar opposite is categorical contrast: distinguishing a difference from a known pattern. Coalition of these antipodes affords object identification and learning.

A unified and universal principle of statistical learning explains a wide range of cognitive processes across domains.
~ Israeli psychologist Ram Frost et al

An object is recognized by perceiving its attributes and comparing them with memories of similar objects, then winnowing those deemed too dissimilar. Spatially or temporally, perceiving more than a single object with akin qualities leads to categorization, which defines object groups.

“Given a thimbleful of facts we rush to make generalizations as large as a tub.” ~ American psychologist Gordon Allport

Categorization tidies the mental clutter of a complex world. The human eye can distinguish over 7 million colors. To simplify we slot colors onto a few dozen labels.

“The world of experience is composed of a tremendous array of discriminably different objects, events, people, impressions. Were we to utilize fully our capacity for registering the differences in things and to respond to each event encountered as unique, we would soon be overwhelmed by the complexity of our environment. The resolution of this seeming paradox – the existence of discrimination capacities, which, if fully used, would leave us slaves to the particular – is achieved by the capacity to categorize. To categorize is to render discriminably different things equivalent, to group the objects and events around us into classes, and to respond to them in terms of their class membership rather than their uniqueness.” ~ American psychologist Jerome Bruner et al

Categorization is essential in determining what constitutes an appropriate action. Decision-making is predicated upon categorization.

 Mental Maps

Cartographers plot distances, but when we make a mental map we rely upon categorization. Risk assessment illustrates.

In one study, participants were asked to imagine building a vacation mountain home in the Pacific Northwest, at specific sites in either Washington or Oregon. While contemplating their choice, a news alert about an earthquake came in; but different groups got different details. Some heard that the quake struck in Oregon, 200 miles from both sites. Others heard that the seismic activity was in Washington, 200 miles from both sites. Both groups were warned of continuing tremors, and shown maps of both home sites, and the earthquake epicenter, to help them make their choice.

Even though both homes were exactly 200 miles from the disaster, participants viewed an in-state location to be significantly riskier than an out-of-state spot. Actual distance made no difference: the risk assessment was based on political borders that had nothing to do with geology or seismology.

Another study looked at environmental risk. Participants were told that a radioactive waste facility was being built 165 miles away. They were warned that if the waste were not properly contained, it could contaminate the soil, water, and air for hundreds of miles. Some subjects were then told that the waste facility would be in the same state. Others were told that the waste would be located out-of-state, the same distance away. To get the point of equidistance across, participants were shown maps, though of 2 different types. Whereas some saw a map where state borders were drawn with thick lines, others were shown a map with state borders in light, dotted lines.

Again, in-state siting was seen as riskier than placing the facility out-of-state. But much greater contamination risk was perceived for out-of-state siting when maps had light border lines. A border line with a darker line was thought to offer some protection.

“The border bias occurs because people apply state-based categorization to events that are not governed by human-made boundaries. Such categorization results in state borders being considered physical barriers that can keep disasters at bay.” ~ Indian psychologists Arul Mishra & Himanshu Mishra


In that certain attributes are more important than others, categorization is a hierarchical ordering. Prioritization of attributes is subconscious. Criteria may vary among individuals, even as the process is largely guided by the biology of the mind.

“Object recognition is the ability to perceive physical properties and apply attributes. The process leading to recognition is typically viewed as a bottom-up hierarchy in which information is processed sequentially with increasing complexity.” ~ New Zealander zoologists Ximena Nelson & Yinnon Dolev

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Based upon experimental studies, various theories attempt to explain how the mind categorizes. They fall into 2 schools: that categorization proceeds either from abstracts or from specific examples.

2 prominent abstract-information theories are the prototype model and the feature-frequency model.

The prototype model proposes the mind creates patterns which best represent categories, then classifies novel objects or occurrences into these prototypes. A prototype is the central tendency of a category, formed by averaging the patterns within. Prototyping works well in predicting perceptual pattern classification when features vary continuously along a dimension.

The feature-frequency model takes the reverse approach to the prototype model by positing that the mind classifies by how frequently features match category patterns, with a category selected via the best feature matches. The feature-frequency model is most successful in predicting how patterns are classified when features do not vary continuously along a dimension.

In contrast to the abstract-information theories, exemplar theories propose that categories are forged from specifics rather than from abstractions. Exemplar models shine after some categories have already been learned; so, exemplar theories necessarily involve heuristics rather than incipient categorization.

As no single theory fully explains how categorization proceeds, the disparate variety suggests nuanced complexity in the mind’s classification process, likely involving a confluence of techniques.

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“The human compulsion to group people and objects together was ingrained in our being since we evolved. We need to group things. Without the ability to categorise threats, our ancestors wouldn’t have survived.” ~ Australian media entrepreneur Charlie Caruso

All theories of categorization assume that the mind uses knowledge of the world to classify patterns rather than proceeding from innate bases. Yet even specifics of categorization are indisputably precocious knowledge.

A newborn can discern a face. A 6-month-old can read emotions on faces to select an appropriate behavior.

Classifications are partly a product of evolutionary descent. There are instinctive faculties and biases built in.

Jumping spiders rapidly categorize objects as prey or not based on only a few key visual features, including movement. The East African jumping spider indirectly feeds on vertebrate blood by preying upon the blood-fed mosquitoes that carry malaria. To distinguish between mosquitoes that have fed and those that have not, a spider considers whether the abdomen is engorged, the mosquito’s resting posture, and its antennae position. Experimenters determined that the discrimination is innate by testing naïve juvenile jumping spiders.

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“Transformations that alter an object’s core properties also tend to change the object’s category, while transformations that alter an object’s surface or incidental properties tend to preserve its category.” ~ Russian American psychologist Sergey Blok et al

A sortal is a categorical object. (Though recorded appreciation of cognitive categorization predates Aristotle, the term sortal was introduced by John Locke in 1690.) By providing a metric for similarity, sortals are essential to counting. In providing a basis for discrimination away from a classification, sortals assist in identifying individuals of certain types.

“Sortals are important because they support crucial aspects of our knowledge of individuals. Sortals determine the identity of individual instances across times and situations (a principle of identity).” ~ Sergey Blok et al

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“Simply having a symbol leads collections of individuals to seem more like real, unified groups.” ~ American social psychologists Shannon Callahan & Alison Legerwood

Organizations have logos, sports teams mascots, nations flags and anthems. To outsiders such symbols of group identification emanate an aura of unification, effectiveness, and coordination, even when members of a group fail to give such impressions. Symbols of classification impart attributes which often do not exist.

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Beyond perception, which is a categorical fabrication only partly based upon sensations, classification is the mind’s preeminent abstraction of the tangible: glossing over incidental details to suss sortals, even as each perceived object is in fact individual and unique.

“All classifications are oppressive.” ~ French philosopher Roland Barthes