Dr Alexandra Grandison (née Clifford)
Academic and research departments
Surrey Baby Lab, School of Psychology, Faculty of Health and Medical Sciences.About
University roles and responsibilities
- Director of the Surrey Baby Lab
- Associate Head of Education for the School of Psychology
News
ResearchResearch interests
Ally Grandison is a Senior Lecturer in Cognitive and Developmental Psychology. Her research focuses on the impact of language on cognition, aiming to uncover how the language we speak influences our experience of the world. Ally investigates different types of linguistic categorisation using a cross-cultural approach throughout the lifespan. She conducts research with infants before they learn language, children as they acquire specific language categories and adults from across the globe whose languages have very different structures. Her work is both basic and applied, employing methods including eye-tracking, fieldwork, psycholinguistic experiments, event-related potentials (ERPs; a measure of brain activity), functional near-infrared spectroscopy (fNIRS; non-invasive brain imaging), gamified experiments, interviews, and questionnaires. Her programme of research holds interdisciplinary value for psychology, linguistics, cognitive science, education, anthropology, and philosophy.
Ally has extensive experience of science communication, appearing on television, radio, podcasts, and in print. She was recently selected for the prestigious Talent Factory Science Communication programme, led by Wellcome Engagement Fellow Dr. Steve Cross. Ally is a Senior Fellow of the Higher Education Academy and an accredited member of the Institute for Leadership.
Research projects
- Effects of culture and experience on colour associations
- Time course and neural markers of categorisation
- Infant and adult colour perception and cognition
- The influence of colour on performance in achievement contexts
- Effect of language on low level perceptual and higher cognitive processes
- Cross-cultural differences in colour perception and cognition
Research skills
- Event-Related Potential technique with infants and adults
- Colour science techniques such as reliable colour measurement
- Experimental techniques for infancy research including infant and toddler eye-tracking and novelty preference
- Cross-cultural fieldwork
Research collaborations
- Dr Isabelle Bril, French National Centre for Scientific Research, France
- Professor Greville Corbett, University of Surrey, UK
- Dr Anne-Laure Dotte, University of New Caledonia, New Caledonia
- Dr Sonja Eisenbeiss, University of Cologne, Germany
- Professor John Everatt, University of Canterbury, New Zealand
- Professor Sebastian Fedden, University of Paris, France
- Dr Michael Franjieh, University of Surrey, UK
- Professor Anna Franklin, University of Sussex, UK
- Dr. Amanda Holmes, University of Roehampton, UK
- Dr. Paul Sowden, University of Winchester, UK
- Dr Diana Tham, Lancaster University, UK
Indicators of esteem
Senior Fellow of the Higher Education Academy
Research interests
Ally Grandison is a Senior Lecturer in Cognitive and Developmental Psychology. Her research focuses on the impact of language on cognition, aiming to uncover how the language we speak influences our experience of the world. Ally investigates different types of linguistic categorisation using a cross-cultural approach throughout the lifespan. She conducts research with infants before they learn language, children as they acquire specific language categories and adults from across the globe whose languages have very different structures. Her work is both basic and applied, employing methods including eye-tracking, fieldwork, psycholinguistic experiments, event-related potentials (ERPs; a measure of brain activity), functional near-infrared spectroscopy (fNIRS; non-invasive brain imaging), gamified experiments, interviews, and questionnaires. Her programme of research holds interdisciplinary value for psychology, linguistics, cognitive science, education, anthropology, and philosophy.
Ally has extensive experience of science communication, appearing on television, radio, podcasts, and in print. She was recently selected for the prestigious Talent Factory Science Communication programme, led by Wellcome Engagement Fellow Dr. Steve Cross. Ally is a Senior Fellow of the Higher Education Academy and an accredited member of the Institute for Leadership.
Research projects
- Effects of culture and experience on colour associations
- Time course and neural markers of categorisation
- Infant and adult colour perception and cognition
- The influence of colour on performance in achievement contexts
- Effect of language on low level perceptual and higher cognitive processes
- Cross-cultural differences in colour perception and cognition
Research skills
- Event-Related Potential technique with infants and adults
- Colour science techniques such as reliable colour measurement
- Experimental techniques for infancy research including infant and toddler eye-tracking and novelty preference
- Cross-cultural fieldwork
Research collaborations
- Dr Isabelle Bril, French National Centre for Scientific Research, France
- Professor Greville Corbett, University of Surrey, UK
- Dr Anne-Laure Dotte, University of New Caledonia, New Caledonia
- Dr Sonja Eisenbeiss, University of Cologne, Germany
- Professor John Everatt, University of Canterbury, New Zealand
- Professor Sebastian Fedden, University of Paris, France
- Dr Michael Franjieh, University of Surrey, UK
- Professor Anna Franklin, University of Sussex, UK
- Dr. Amanda Holmes, University of Roehampton, UK
- Dr. Paul Sowden, University of Winchester, UK
- Dr Diana Tham, Lancaster University, UK
Indicators of esteem
Senior Fellow of the Higher Education Academy
Teaching
- Thought and Language, FHEQ Level 6 (Year 3), module convenor 2010-present
- Thinking Psychologically, FHEQ Level 3 (Foundation Year), 2020-present
- Undergraduate and Postgraduate Dissertation supervision, 2010-present
- Social and Cognitive Development with Research Methods, FHEQ Level 7 (MSc), 2022-2024
- Developmental Psychology with Research Methods, FHEQ Level 5 (Year 2), 2022-2024
- Cognitive Psychology, FHEQ Level 5 (Year 2), module convenor 2010-2018
- Cognitive Psychology, FHEQ Level 4 (Year 1), module convenor 2010-2015
- Academic Tutorial Programme, FHEQ Level 4 (Year 1), module convenor 2014-2015
- Perception and Cognition, FHEQ Level 7 (MSc), module convenor 2014-2015
- Aspects of Experimental Psychology, FHEQ Level 7 (MSc), 2010-2015
- Personal and Professional Development, Professional Training Year, module co-convenor 2012-2014
- Evaluation of Placement Learning, Professional Training Year, module co-convenor 2012-2014
- Transfer of Placement Learning, Professional Training Year, module co-convenor 2012-2014
- Professional Skills and Applied Psychology, FHEQ Level 5 (Year 2), module co-convenor 2011-2014
Publications
Literacy, language and teacher training survey conducted with schools from the Merei, North Ambrym and Vatlongos language communities in Vanuatu in June/July 2023. The survey was conducted as part of the project on Sustainable Endangered Language Maintenance in the South Pacific, funded by the University of Surrey’s Economic and Social Research Council (ESRC) Impact Acceleration Account.
A vernacular literacy education survey with teachers from three language communities in Vanuatu. Our main objective was to understand more about the experiences of using the local vernacular language as the Medium of Instruction (MOI). Though this research is a pilot study, the results are intended to inform current education policy. In particular the study’s main aims are to understand:
1. Teachers’ perspectives on speaking and using the main community language in the classroom and what training they require.
2. How many children speak the main community language in each community and their enjoyment of using the language in the classroom.
3. What further teaching resources are essential for effectively using the community language as the MOI.
Happy Families Card Game of Possession in the iaai Language
An innovative card game based on happy families / jeu de sept familles where players collect the 'family' of nouns that go with a specific possessive classifier. With instructions in Fench and Iaai.
Cards designed and illustrated by Isabelle Ritzenthaler.
Possession in Iaai: grammar and lexicon.
A pedagogical grammar of possessive constructions in Iaai (a language of New Caledonia). The grammar is written in English and French. The dictionary shows which nouns occur with which possessive constructions and which nouns occur with each possessive classifier, informed by a free-listing experiment.
Illustrated by Isabelle Ritzenthaler.
A creative 1 minute video about the optimal categorisation project and our community outputs for a general audience. Created for the Nature science in shorts video competition: https://www.nature.com/immersive/scienceinshorts/index.html
Possession in Vatlongos: grammar and dictionary.
A pedagogical grammar of possessive constructions in Vatlongos (also known as South East Ambrym, a language of Vanuatu). The grammar is written in Bislama, English and French. The dictionary shows which nouns occur with which possessive constructiuons and which nouns occur with each possessive classifier, informed by a free-listing experiment.
Ilustrated by Isabelle Ritzenthaler.
As part of the attempt to understand the linguistic origin and cognitive nature of grammatical gender, we designed six psycholinguistic experiments for our language sample from Vanuatu (Merei, Lewo, Vatlongos, North Ambrym) and New Caledonia (Nêlêmwa, Iaai). Each language differs in number of classifiers, and whether nouns can freely occur with different classifiers, or are restricted to just one classifier (similar to grammatical gender). Free-listing: participants heard a possessive classifier and listed associated nouns. This revealed the different semantic domains of classifiers, the salient nouns associated with each classifier, and showed whether participants listed the same noun with different classifiers. Card-sorting: Participants free-sorted sixty images, followed by a structured sort according to which classifier they used with each picture. We compared whether similar piles were made across sorting tasks to reveal whether the linguistic classification system provides a structure for general cognition. Video-vignettes: Participants described 24 video clips which showed different interactions between an actor and their possession, evoking a classifier. This tested both typical and atypical interactions to see if the same or different classifiers were used. Possessive-labelling: Participants heard 140 nouns in their language and responded by saying the item belonged to them, which meant using a classifier. This measured* inter-speaker variation in the use of classifiers for particular items, reaction times and inter-speaker variation for different possessions. Storyboards: eight four-picture storyboards were presented to participants. We recorded participant responses, uncovering if the same classifier was used in consecutive parts of the larger story and whether the classifiers were used anaphorically. Eye-tracking: eight line-drawn pictures were combined in a paired-preference design. An eye tracker recorded fixation times. Participants heard the auditory cue of a classifier before being presented with a pair of images. This provided objective measures of automatic processing to identify patterns in attention.
Possession in Rral: grammar and dictionary.
A pedagogical grammar of possessive constructions in Rral (also known as North Ambrym, a language of Vanuatu). The grammar is written in Bislama, English and French. The dictionary shows which nouns occur with which possessive constructiuons and which nouns occur with each possessive classifier, informed by a free-listing experiment.
Ilustrated by Isabelle Ritzenthaler.
Possession in Lewo: grammar and dictionary.
A pedagogical grammar of possessive constructions in Lewo (a language of Vanuatu). The grammar is written in Bislama, English and French. The dictionary shows which nouns occur with which possessive constructiuons and which nouns occur with each possessive classifier, informed by a free-listing experiment.
Ilustrated by Isabelle Ritzenthaler.
Possession in Iaai: Stories
A collection of six simple stories in Iaai (a language of New Caledonia). The stories have gaps in them where readers can choose the correct possessive classifier that goes with the noun.
Ilustrated by Erin Aniker.
Possession in Lewo: Stories
A collection of six simple stories in Lewo (a language of Vanuatu). The stories have gaps in them where readers can choose the correct possesive classifier that goes with the noun.
Ilustrated by Erin Aniker.
Possession in Rral: Stories
A collection of six simple stories in Rral (also known as North Ambrym, a language of Vanuatu). The stories have gaps in them where readers can choose the correct possesive classifier that goes with the noun.
Ilustrated by Erin Aniker.
Possession in Vatlongos: Stories
A collection of six simple stories in Vatlongos (also known as Southeast Ambrym, a language of Vanuatu). The stories have gaps in them where readers can choose the correct possesive classifier that goes with the noun.
Ilustrated by Erin Aniker.
We evaluate the design and implementation of the free-list experiment, which is a relatively easy method for exploring the membership of semantic categories (Weller and Romney 1988). Different factors that could affect the replicability and validity of the experiment are explored, and these are balanced with the need to work sensitively with speakers of endangered and minority language communities. By including aspects of a Participatory Research approach (van der Riet and Boettiger 2009), such as building rapport and respecting participants’ knowledge, the experimenter can extend the free-list experiment to include wider discussions around the linguistic categories under study. We include a case study from our research on Oceanic possessive classifiers to show that a free-list experiment results in a wealth of data, and offers up opportunities for discussing and valorising different speakers’ understanding of linguistic categories.
We discuss the results of a video vignettes experiment that uncovers the variation of noun-classifier assignment in the possessive classifier system of six Oceanic languages. The results show that languages vary in their noun-classifier assignment, with some languages displaying relatively fixed assignment, similar to a grammatical gender system.
The debate as to whether language influences cognition has been long standing but has yielded conflicting findings across domains such as colour and kinship categories. Fewer studies have investigated systems such as nominal classification (gender, classifiers) across different languages to examine the effects of linguistic categorisation on cognition. Effective categorisation needs to be informative to maximise communicative efficiency but also simple to minimise cognitive load. It therefore seems plausible to suggest that different systems of nominal classification have implications for the way speakers conceptualise relevant entities. A suite of seven experiments was designed to test this; here we focus on our card sorting experiment, which contains two sub-tasks — a free sort and a structured sort. Participants were 119 adults across six Oceanic languages from Vanuatu and New Caledonia, with classifier inventories ranging from two to 23. The results of the card sorting experiment reveal that classifiers appear to provide structure for cognition in tasks where they are explicit and salient. The free sort task did not incite categorisation through classifiers, arguably as it required subjective judgement, rather than explicit instruction. This was evident from our quantitative and qualitative analyses. Furthermore, the languages employing more extreme categorisation systems displayed smaller variation in comparison to more moderate systems. Thus, systems that are more informative or more rigid appear to be more efficient. The study implies that the influence of language on cognition may vary across languages, and that not all nominal classification systems employ this optimal trade-off between simplicity and informativeness. These novel data provide a new perspective on the origin and nature of nominal classification.
Associations with colors are a rich source of meaning, and there has been considerable interest in understanding the capacity of color to shape our functioning and behavior as a result of color associations. However, abstract conceptual color associations have not been comprehensively investigated, and many of the effects of color on psychological functioning reported in the literature are therefore reliant on ad hoc rationalizations of conceptual associations with color (e.g., blue = openness) to explain effects. In the present work we conduct a systematic, cross-cultural, mapping of conceptual color associations using the full set of hues from the World Color Survey (WCS). In Experiments 1a and 1b we explored the conceptual associations that English monolingual, Chinese bilingual, and Chinese monolingual speaking adults have with each of the 11 Basic English Color Terms (black, white, red, yellow, green, blue, brown, purple, pink, orange, gray). In Experiment 2 we determined which specific physical WCS colors are associated with which concepts in these three language groups. The findings reveal conceptual color associations that appear to be universal across all cultures (e.g., white - purity; blue - water/skyrelated; green - health; purple - regal; pink - "female" traits) as well as culture specific (e.g., red and orange - enthusiastic in Chinese; red - attraction in English). Importantly, the findings provide a crucial constraint on, and resource for, future work that seeks to understand the effect of color on cognition and behavior, enabling stronger a priori predictions about universal as well as culturally relative effects of conceptual color associations on cognition and behavior to be systematically tested.
The rise of feminist and LGBTQIA+ movements paved the way for many equality reforms. These include language reforms, which facilitate inclusion of multiple groups in society. For example, the shift from the generic “he” to “he or she” and “they” allows for the inclusion of women, transgender, and non-binary individuals in many narratives. For this reason, many institutions worldwide encourage neutral language. It remains unclear how individuals interpret neutral language. One case of neutral language is the pronoun “they,” which has been assigned multiple definitions from the 1970s to 2022. We examine how the pronoun “they” has been interpreted, used, and accepted over time. We discuss trends in the findings and make suggestions for future research directions, including the need for better methods to investigate pronouns and clarification on what the focus of neutral language should be. This timely commentary has implications for action on equality, diversity, and inclusion.
There are multiple lenses through which contemporary witchcraft practtioners are perceived in literature: self-identification; mainstream stereotyping; and counterculture. Contemporary witchcraft is a sociocultural phenomenon that has not received much attention outside of the disciplines of anthropology and sociology. Therefore, the individual views and experiences of self-identified practitioners have arguably been diluted within social research due to an emphasis on historical or group-based observations. With the aim of incorporating a psychological perspective into existing contemporary literature, the current study used semi-structured interviews to explore how practitioners personally engage with online communities to navigate the individual, social, and collective interpretations of their ‘witchcraft-related identity’. Using data from 16 participant interviews, it emerged that digitising witchcraft practices served two key roles in engaging with the practitioners’ identities by providing access to both group membership and interactive knowledge exchange. Positive and negative aspects of these experiences were discussed. Moreover, it was found that the relationship between online and face-to-face constructions of being ‘a witch’ was observably fluid, wherein digital practices could help practitioners compartmentalise their witchcraft-related identity to online spaces or, alternatively, enhance its in-person identity saliency. This investigation offers timely and novel insights into contemporary witchcraft by taking a psychological perspective that contributes to broader debates about the notion of identity and how this manifests in online communities.
This chapter focuses on two key challenges that higher education (HE) institutions face when embedding work-based learning (WBL) into their curricula, and the roles that disparate voices play in each. First, we reflect on diversity among students in terms of their needs for WBL in relation to their employability. Considering such diversity, we focus on international students as one key example. Second, we discuss the tensions that arise between the voices of students and employers about their understanding of employability. We argue that greater insight into these voices is needed to move towards a shared understanding of employability. In turn, this will enable HE institutions to maximise the value of their programmes to enable collective actions that empower and benefit students, educators, and employers alike.
A review was conducted to explore possible consequences of deuteranomaly, a specific type of congenital colour vision deficiency (CVD), for children in education. Electronic searches of five databases were performed. Key search terms included: child*, colo?r vision, colo?r blind*, colour def*, deuter*, education*, health*, wellbeing, occupation*, to identify empirical studies published in English during the period 1990–2016. Analysis provided evidence of challenges to school students with congenital vision deficiencies, and the impact of deuteranomaly in educational settings. Four themes emerged: (1) requirements for deciphering colour-coding that may affect educational attainment; (2) mental health and wellbeing; (3) implications for future occupational choices, and (4) relation of chromatic discrimination to certain cognitive abilities. The findings prompt recommendation of certain interventions, specifically relating to colour vision screening at early school age, and raising awareness of challenges of school students with deuteranomaly.
Perceptual learning involves an improvement in perceptual judgment with practice, which is often specific to stimulus or task factors. Perceptual learning has been shown on a range of visual tasks but very little research has explored chromatic perceptual learning. Here, we use two low level perceptual threshold tasks and a supra-threshold target detection task to assess chromatic perceptual learning and category effects. Experiment 1 investigates whether chromatic thresholds reduce as a result of training and at what level of analysis learning effects occur. Experiment 2 explores the effect of category training on chromatic thresholds, whether training of this nature is category specific and whether it can induce categorical responding. Experiment 3 investigates the effect of category training on a higher level, lateralized target detection task, previously found to be sensitive to category effects. The findings indicate that performance on a perceptual threshold task improves following training but improvements do not transfer across retinal location or hue. Therefore, chromatic perceptual learning is category specific and can occur at relatively early stages of visual analysis. Additionally, category training does not induce category effects on a low level perceptual threshold task, as indicated by comparable discrimination thresholds at the newly learned hue boundary and adjacent test points. However, category training does induce emerging category effects on a supra-threshold target detection task. Whilst chromatic perceptual learning is possible, learnt category effects appear to be a product of left hemisphere processing, and may require the input of higher level linguistic coding processes in order to manifest.
The hue spectrum is a continuum of light, yet we perceive it categorically. The categories used to describe this continuum vary across the world’s languages and there are marked differences in the numbers of colour categories and the locations of category boundaries. For example, the green–blue region of colour space is labelled with two terms in English but with only one term (a “grue” term) in many African languages. Evidence for a “grue” term in Otjiherero – a language spoken by the Himba of northern Namibia – has been well documented. Here we present data from colour list and colour naming tasks indicating the emergence of a new Himba colour term. These findings have significant implications for future cross-cultural research into colour categorization.
Prior claims that color categories affect color perception are confounded by inequalities in the color space used to equate same- and different-category colors. Here, we equate same- and different-category colors in the number of just-noticeable differences, and measure event-related potentials (ERPs) to these colors on a visual oddball task to establish if color categories affect perceptual or post-perceptual stages of processing. Category effects were found from 200 ms after color presentation, only in ERP components that reflect post-perceptual processes (e.g., N2, P3). The findings suggest that color categories affect post-perceptual processing, but do not affect the perceptual representation of color.
Claims of universality pervade color preference research. It has been argued that there are universal preferences for some colors over others (e.g., Eysenck, 1941), universal sex differences (e.g., Hurlbert & Ling, 2007), and universal mechanisms or dimensions that govern these preferences (e.g., Palmer & Schloss, 2010a). However, there have been surprisingly few cross-cultural investigations of color preference, and none from non-industrialised societies that are relatively free from the common influence of global consumer culture. Here, we compare the color preferences of British adults to those of Himba adults who belong to a non-industrialised culture in rural Namibia. British and Himba color preferences are found to share few characteristics, and Himba color preferences display none of the so-called ‘universal’ patterns or sex differences. Several significant predictors of color preference are identified such as cone-contrast between stimulus and background (Hurlbert & Ling, 2007), the valence of color-associated objects (Palmer & Schloss, 2010a), and the colorfulness of the color. However, the relationship of these predictors to color preference was strikingly different for the two cultures. No one model of color preference is able to account for both British and Himba color preferences. We suggest that not only do patterns of color preference vary across individuals and groups, but that the underlying mechanisms and dimensions of color preference vary as well. The findings have implications for broader debate on the extent to which our perception and experience of color is culturally relative or universally constrained.
Category training can induce category effects, whereby color discrimination of stimuli spanning a newly learned category boundary is enhanced relative to equivalently spaced stimuli from within the newly learned category (e.g., categorical perception). However, the underlying mechanisms of these acquired category effects are not fully understood. In the current study, Event-Related Potentials (ERPs) were recorded during a visual oddball task where standard and deviant colored stimuli from the same or different novel categories were presented. ERPs were recorded for a test group who were trained on these novel categories, and for an untrained control group. Category effects were only found for the test group on the trained region of color space, and only occurred during post-perceptual stages of processing. These findings provide new evidence for the involvement of cognitive mechanisms in acquired category effects and suggest that category effects of this kind can exist independent of early perceptual processes.
Categorical perception (CP) of colour is demonstrated by faster and more accurate discrimination of colours that cross a category boundary than equivalently spaced colours from the same colour category. Despite a plethora of behavioural research investigating the origin and nature of colour CP, the underlying mechanisms involved in the effect are still unresolved. A recent body of work has made use of the Event-Related Potential (ERP) technique, which involves the measurement of event-related brain potentials at the scalp, enabling exploration of the time course of neural processes that are involved in colour CP. The merits of the ERP technique are presented and five studies that have used this approach to investigate colour CP and colour categorization are reviewed. Each is discussed in relation to the debate about the origin and nature of colour category effects.
There is indirect evidence that categorical colour perception (better discrimination of colours from different categories than those from the same category). For instance, CP can be induced across a newly learned category boundary (Özgen & Davies 2002). Here we replicate and extend Özgen and Davies’s category learning study to try and pinpoint the nature of the changes underlying category learning. Participants learned to divide green into two new categories ‘yellow-green’/‘blue-green’ across four days. The trained group showed CP across the new boundary on a target detection task and this was restricted to the left hemisphere (LH; cf. Drivonikou et al. 2007), whereas the controls did not. The results could suggest that category training produces changes at early stages in visual processing mainly in the LH.
Categorical perception (CP) of color is the faster and/or more accurate discrimination of colors from different categories than equivalently spaced colors from the same category. Here, we investigate whether color CP at early stages of chromatic processing is independent of top–down modulation from attention. A visual oddball task was employed where frequent and infrequent colored stimuli were either same- or different-category, with chromatic differences equated across conditions. Stimuli were presented peripheral to a central distractor task to elicit an event-related potential (ERP) known as the visual mismatch negativity (vMMN). The vMMN is an index of automatic and pre-attentive visual change detection arising from generating loci in visual cortices. The results revealed a greater vMMN for different-category than same-category change detection when stimuli appeared in the lower visual field, and an absence of attention-related ERP components. The findings provide the first clear evidence for an automatic and pre-attentive categorical code for color.
The origin of color categories has been debated by psychologists, linguists and cognitive scientists for many decades. Here, we present the first electrophysiological evidence for categorical responding to color before color terms are acquired. Event-related potentials were recorded on a visual oddball task in 7-month old infants. Infants were shown frequent presentations of one color (standard) interspersed with infrequent presentations of a color that was either from the same category (within-category deviant) or from a different category (between-category deviant) to the standard. Differences in the event-related potentials elicited by the stimuli were found that were related to the categorical relationship of the standard and the deviant stimuli. The data are discussed in relation to the processes that underlie categorical responding in infancy, as well as the debate about the origin of color categories in language and cognition.
The aim of this investigation was to examine the time course and the relative contributions of perceptual and post-perceptual processes to categorical perception (CP) of color. A visual oddball task was used with standard and deviant stimuli from same (within-category) or different (between-category) categories, with chromatic separations for within- and between-category stimuli equated in Munsell Hue. CP was found on a behavioral version of the task, with faster RTs and greater accuracy for between- compared to within-category stimuli. On a neurophysiological version of the task, event-related potentials (ERPs) showed earlier latencies for P1 and N1 components at posterior locations to between- relative to within-category deviants, providing novel evidence for early perceptual processes on color CP. Enhanced P2 and P3 waves were also found for between- compared to within-category stimuli, indicating a role for later post-perceptual processes.
Categorical perception (CP) of color is the faster and more accurate discrimination of two colors from different categories than two colors from the same category, even when same- and different-category chromatic separations are equated. In adults, color CP is lateralized to the left hemisphere (LH), whereas in infants, it is lateralized to the right hemisphere (RH). There is evidence that the LH bias in color CP in adults is due to the influence of color terms in the LH. Here we show that the RH to LH switch in color CP occurs when the words that distinguish the relevant category boundary are learned. A colored target was shown in either the left- or right-visual field on either the same- or different-category background, with equal hue separation for both conditions. The time to initiate an eye movement toward the target from central fixation at target onset was recorded. Color naming and comprehension was assessed. Toddlers were faster at detecting targets on different- than same-category backgrounds and the extent of CP did not vary with level of color term knowledge. However, for toddlers who knew the relevant color terms, the category effect was found only for targets in the RVF (LH), whereas for toddlers learning the color terms, the category effect was found only for targets in the LVF (RH). The findings suggest that lateralization of color CP changes with color term acquisition, and provide evidence for the influence of language on the functional organization of the brain.
In adults, visual search for a colour target is facilitated if the target and distractors fall in different colour categories (e.g. Daoutis, Pilling, & Davies, in press). The present study explored category effects in children's colour search. The relationship between linguistic colour categories and perceptual categories was addressed by comparing native speakers of languages differing in the number of colour terms. Experiment 1 compared English and Kwanyama (Namibian) children aged 4 to 7 years on a visual search task, using target-distractor pairs (blue-green, blue-purple, red-pink) for which the Kwanyama did not have distinct names. The presence of a category advantage in the English, but not in the Kwanyama, suggested that linguistic boundaries may affect search performance. Experiment 2 examined visual search performance in the green-yellow and the blue-green region, in English and Himba (Namibian) 6-year-olds. The number of distractors was varied to assess search efficiency. Cross-category search was more efficient than within-category search in the English group, but this advantage was absent in the Himba. Increasing the number of distractors affected search speed in the English group, but not in the Himba. Overall, these findings suggest cross-language differences in categorical effects on colour search, but also in the way the children performed the search. The nature of the category effect in search is discussed with respect to these findings.
Categorical perception of color is shown when colors from the same category are discriminated less easily than equivalently spaced colors that cross a category boundary. The current experiments tested various models of categorical perception. Experiment 1 tested for categorical responding in 2- to 4-year-olds, the age range for the onset establishment of color term knowledge. Experiment 2 tested for categorical responding in Himba toddlers, whose language segments the color space differently from the way in which the English language does so. Experiment 3 manipulated the conditions of the task to explore whether the categorical responding in Experiments 1 and 2 was equivalent to categorical perception. Categorical perception was shown irrespective of naming and was not stronger in those children with more developed color term knowledge. Cross-cultural differences in the extent of categorical perception were not found. These findings support universalistic models of color categorization and suggest that color term knowledge does not modify categorical perception, at least during the early stages of childhood.