Lexical Color Categories

Kafka's beautiful eyes: Forensic intelligence utilisation of phenotypic information

Franz Kafka had beautiful eyes. So striking, that many of the famous author's friends and peers commented on them - but quite variously ('dark', 'brown', 'grey' & 'blue'). Eye colour as perceived by an observer is subjective, being influenced by physiological, environmental, and even sociocultural factors. In a policing context, this does not mean that trait information such as eye colour is not valuable (far from it), but that it must be managed carefully. The Australian Federal Police has recently implemented a forensic DNA phenotyping (FDP, aka. physical trait prediction or PTP) capability, utilising massively parallel sequencing DNA technology to predict an individual's eye colour, biogeographical ancestry and sex from a crime scene sample. This information alone is not itself 'intelligence', but can be used to generate intelligence through holistic analyses undertaken within a transdisciplinary, all-source forensic intelligence (FORINT) framework. FORINT outputs posit abductive propositions typically at the activity/offence level, to provide insight and influence decision making. However, the use of predicted traits requires that they are compared to something; all Australian police databases include fields for physical traits, but no uniform standard is applied across all agencies. Moreover, collection is inconsistent and no automated systems are in place to capture such data systematically. Consider the 'Kafka problem': his peers gave multiply divergent descriptions of his eyes. If a Biology unit had predicted the eye colour of an 'unidentified author' using DNA - how would Kafka be confidently nominated as the contributor? We posit three maxims for law enforcement: (1) To expand the operational utility of forensic science in line with police demands, forensic science should operationalise FDP (e.g. operationally to rank a list of persons of interest, focus lines of enquiry in serious & organised crime, or assist with human remains identification). (2) Such advanced biological techniques are best delivered through an all-source FORINT framework, to maximise opportunities and minimise risk. (3) One cannot pursue techno-scientific advancements in isolation; it is also necessary to influence the operational posture for their implementation. In this paper we explore these issues and provide recommendations relating to (a) police practices, (b) image capture systems, and (c) research opportunities. Phenotypic trait prediction has great potential and can be operationalised effectively through a rigorous FORINT framework. However, there is (continual) work to be done to enhance the operational capabilities that are complementary to - but necessary for - effective forensic science contribution to investigations.

"Warm," "cool," and the colors

Participants judged affective cooler/warmer gradients around a 12-step color circle. Each pair of adjacent colors was presented twice (left-right reversed), all in random order. Participants readily performed the task, but their settings do not correlate very well. Individual responses were compared with a small number of canonical templates. For a little less than one-half of the participants responses or judgements correlate with such a template. We find a warm pole (in the orange environment) and a cool pole (in the teal environment) connected with two tracks that tend to have one or more gaps or weak, even inverted links. We conclude that the common artistic cool-warm polarity is only weakly reflected in responses of our observers. If it does, the observers apparently use categorical warm and cool poles and may be uncertain in relating adjacent hue steps along the 12-step color circle.

Acquisition of colour categories through learning: Differences between hue and lightness

Colour categories are acquired through learning, but the nature of this process is not fully understood. Some category distinctions are defined by hue (e.g. red/purple) but other by lightness (red/pink). The aim of this study was to investigate if the acquisition of key information for making accurate cross-boundary discriminations poses different challenges for hue-defined as opposed to lightness-defined boundaries. To answer this question, hue- and lightness-learners were trained on a novel category boundary within the GREEN region of colour space. After training, hue- and lightness-learners as well as untrained controls performed delayed same-different discrimination for lightness and hue pairs. In addition to discrimination data, errors during learning and category-labelling strategies were examined. Errors during learning distributed non-uniformly and in accordance with the Bezold-Brücke effect, which accounts for darker colours at the green-blue boundary appearing greener and lighter colours appearing bluer. Only hue-learners showed discrimination improvements due to category boundary acquisition. Thus, acquisition is more efficient for hue-category compared to lightness-category boundaries. Almost all learners reported using category-labelling strategies, with hue-learners almost exclusively using 'green'/'blue' and lightness learners using a wider range of labels, most often 'light'/'dark'. Thus, labels play an important role in colour category learning and such labelling does not conform to everyday naming: here, the label 'blue' is used for exemplars that would normally be named 'green'. In conclusion, labelling serves the purpose of highlighting key information that differentiates exemplars across the category boundary, and basic colour terms may be particularly effective in facilitating such attentional guidance.

The color communication game

There is clear diversity among speakers of a typical language in how colors are named. What is the impact of this diversity on the people's ability to communicate about color? Is there a gap between a person's general understanding of the color terms in their native language and how they understand a particular term that denotes a particular color sample? Seventy English-speaking dyads and 63 Somali-speaking dyads played the Color Communication Game, where the "sender" in each dyad named 30 color samples as they would in any color-naming study, then the "receiver" chose the sample they thought the sender intended to communicate. English speakers played again, under instructions to intentionally communicate color sample identity. Direct comparison of senders' samples and receivers' choices revealed categorical understanding of colors without considering color naming data. Although Somali-speaking senders provided fewer color terms, interpersonal Mutual Information (MI) calculated from color naming data was similarly below optimal for both groups, and English-speaking dyads' MI did not improve with experience. Both groups revealed superior understanding of color terms because receivers showed better exactly-correct selection performance than was predicted by simulation from their senders' color-naming data. This study highlights limitations on information-theoretic analyses of color naming data.

Color appearance and the end of Hering's Opponent-Colors Theory

Hering's Opponent-Colors Theory has been central to understanding color appearance for 150 years. It aims to explain the phenomenology of colors with two linked propositions. First, a psychological hypothesis stipulates that any color is described necessarily and sufficiently by the extent to which it appears reddish-versus-greenish, bluish-versus-yellowish, and blackish-versus-whitish. Second, a physiological hypothesis stipulates that these perceptual mechanisms are encoded by three innate brain mechanisms. We review the evidence and conclude that neither side of the linking proposition is accurate: the theory is wrong. We sketch out an alternative, Utility-Based Coding, by which the known retinal cone-opponent mechanisms represent optimal encoding of spectral information given competing selective pressure to extract high-acuity spatial information; and phenomenological color categories represent an adaptive, efficient, output of the brain governed by behavioral demands.

The Development of Color Perception and Cognition

Color is a pervasive feature of our psychological experience, having a role in many aspects of human mind and behavior such as basic vision, scene perception, object recognition, aesthetics, and communication. Understanding how humans encode, perceive, talk about, and use color has been a major interdisciplinary effort. Here, we present the current state of knowledge on how color perception and cognition develop. We cover the development of various aspects of the psychological experience of color, ranging from low-level color vision to perceptual mechanisms such as color constancy to phenomena such as color naming and color preference. We also identify neurodiversity in the development of color perception and cognition and implications for clinical and educational contexts. We discuss the theoretical implications of the research for understanding mature color perception and cognition, for identifying the principles of perceptual and cognitive development, and for fostering a broader debate in the psychological sciences.

Do You See What I See? Diversity in Human Color Perception

In our tendency to discuss the objective properties of the external world, we may fail to notice that our subjective perceptions of those properties differ between individuals. Variability at all levels of the color vision system creates diversity in color perception, from discrimination to color matching, appearance, and subjective experience, such that each of us lives in a unique perceptual world. In this review, I discuss what is known about individual differences in color perception and its determinants, particularly considering genetically mediated variability in cone photopigments and the paradoxical effects of visual environments in both contributing to and counteracting individual differences. I make the case that, as well as being of interest in their own right and crucial for a complete account of color vision, individual differences can be used as a methodological tool in color science for the insights that they offer about the underlying mechanisms of perception. Expected final online publication date for the Annual Review of Vision Science, Volume 8 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.