Geometrical structure of perceptual color space: Mental representations and adaptation invariance

AbstractA central issue in neuroscience is to understand how the brain builds structured representations of percepts that facilitate useful inferences about the world. Similarity between percepts is used to accomplish many everyday tasks, e.g. object identification, so is widely used to construct geometrical spaces that represent stimulus qualities, but the intrinsic validity of the geometry is not tested critically. We introduce an experimental approach to equating relative similarities by setting perceived midpoints between pairs of stimuli. Midpoint settings are used with Varignon’s Theorem to test the intrinsic geometry of a representation space, and its mapping to a physical space of stimuli. For perceptual color space, we demonstrate that geometrical structure depends on the mental representation used in judging similarity: an affine geometry is valid only when observers use an opponent-color mental representation. An affine geometry implies that similarity can be judged within straight lines and across parallel lines, and its neural coding could involve ratios of responses. We show that this perceptual space is invariant to changes in illumination color, providing a formal justification to generalize to all of color space, color constancy results measured for color categories. Our midpoint measurements deviate significantly from midpoints in the “uniform” color spaces CIELAB and CIELUV, used extensively in industry and research, so these spaces do not provide adequate metric representation of perceived colors. Our paradigm can thus test for intrinsic geometrical assumptions underlying the representation space for many perceptual modalities, and for the extrinsic perceptual geometry of the space of physical stimuli.SignificanceMathematical spaces based on similarity judgments are widely used to represent stimulus qualities in perception, cognition and neuroscience. We introduce a perceptual approach to equate relative similarities, and use them to test the geometry of a perceptual space and its mapping to a physical space of stimuli. For color perception, our results show that perceptual geometry depends on the mental representation used in judging similarity, and it has an affine structure when observers use an opponent-color representation. An affine geometry implies that neural coding of similarity could involve simple ratios of responses. Our measurements also reveal that the uniform color spaces CIELAB and CIELUV, used extensively in industrial applications, do not provide adequate representation of similarity between moderately spaced colors.

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Geometrical structure of perceptual color space is affine

Journal of Vision ◽

10.1167/13.9.295 ◽

2013 ◽

Vol 13 (9) ◽

pp. 295-295

Author(s):

R. Ennis ◽

Q. Zaidi

Keyword(s):

Geometrical Structure ◽

Color Space

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Mental representation of economic crisis in Italian and Swiss samples 1The authors would like to thank Maurizio Mistri for his help in the construction of items. This research was supported by a grant from the Italian Murst (ex 40%).

Swiss Journal of Psychology ◽

10.1024//1421-0185.60.1.11 ◽

2001 ◽

Vol 60 (1) ◽

pp. 11-14 ◽

Cited By ~ 10

Author(s):

Lucia Savadori ◽

Eraldo Nicotra ◽

Rino Rumiati ◽

Roberto Tamborini

Keyword(s):

Economic Crisis ◽

Mental Representation ◽

Mental Representations ◽

Social Contexts ◽

Raw Material ◽

National Context ◽

Cluster Procedure ◽

Total N ◽

Two Samples ◽

Important Symptom

The content and structure of mental representation of economic crises were studied and the flexibility of the structure in different social contexts was tested. Italian and Swiss samples (Total N = 98) were compared with respect to their judgments as to how a series of concrete examples of events representing abstract indicators were relevant symptoms of economic crisis. Mental representations were derived using a cluster procedure. Results showed that the relevance of the indicators varied as a function of national context. The growth of unemployment was judged to be by far the most important symptom of an economic crisis but the Swiss sample judged bankruptcies as more symptomatic than Italians who considered inflation, raw material prices and external accounts to be more relevant. A different clustering structure was found for the two samples: the locations of unemployment and gross domestic production indicators were the main differences in representations.

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The Impact of Visual Stereotypes on Judgments about Rape

Swiss Journal of Psychology ◽

10.1024/1421-0185/a000178 ◽

2016 ◽

Vol 75 (3) ◽

pp. 133-140

Author(s):

Robert Busching ◽

Johannes Lutz

Keyword(s):

Mental Representations ◽

Irrelevant Information ◽

Clear Distinction ◽

Rape Myth ◽

Facial Features ◽

Reverse Correlation ◽

Correlation Technique ◽

Specific Effects ◽

Legal Judgments ◽

The Impact

Abstract. Legally irrelevant information like facial features is used to form judgments about rape cases. Using a reverse-correlation technique, it is possible to visualize criminal stereotypes and test whether these representations influence judgments. In the first step, images of the stereotypical faces of a rapist, a thief, and a lifesaver were generated. These images showed a clear distinction between the lifesaver and the two criminal representations, but the criminal representations were rather similar. In the next step, the images were presented together with rape scenarios, and participants (N = 153) indicated the defendant’s level of liability. Participants with high rape myth acceptance scores attributed a lower level of liability to a defendant who resembled a stereotypical lifesaver. However, no specific effects of the image of the stereotypical rapist compared to the stereotypical thief were found. We discuss the findings with respect to the influence of visual stereotypes on legal judgments and the nature of these mental representations.

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Do Writing Directions Influence How People Map Space onto Time?

Swiss Journal of Psychology ◽

10.1024/1421-0185/a000215 ◽

2018 ◽

Vol 77 (4) ◽

pp. 173-184

Author(s):

Wenxing Yang ◽

Ying Sun

Keyword(s):

Mental Representations ◽

Space Time ◽

Horizontal Axis ◽

Causal Role ◽

Writing Systems ◽

Temporal Cognition ◽

Japanese Speakers ◽

Psychological Experiments ◽

Vertical Up

Abstract. The causal role of a unidirectional orthography in shaping speakers’ mental representations of time seems to be well established by many psychological experiments. However, the question of whether bidirectional writing systems in some languages can also produce such an impact on temporal cognition remains unresolved. To address this issue, the present study focused on Japanese and Taiwanese, both of which have a similar mix of texts written horizontally from left to right (HLR) and vertically from top to bottom (VTB). Two experiments were performed which recruited Japanese and Taiwanese speakers as participants. Experiment 1 used an explicit temporal arrangement design, and Experiment 2 measured implicit space-time associations in participants along the horizontal (left/right) and the vertical (up/down) axis. Converging evidence gathered from the two experiments demonstrate that neither Japanese speakers nor Taiwanese speakers aligned their vertical representations of time with the VTB writing orientation. Along the horizontal axis, only Japanese speakers encoded elapsing time into a left-to-right linear layout, which was commensurate with the HLR writing direction. Therefore, two distinct writing orientations of a language could not bring about two coexisting mental time lines. Possible theoretical implications underlying the findings are discussed.

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Images of Aging in the Psychotherapeutic Context

GeroPsych ◽

10.1024/1662-9647/a000129 ◽

2015 ◽

Vol 28 (2) ◽

pp. 47-55 ◽

Cited By ~ 10

Author(s):

Eva-Marie Kessler ◽

Catherine E. Bowen

Keyword(s):

Old Age ◽

Diagnostic Tests ◽

Aging Process ◽

Developmental Psychology ◽

Mental Representations ◽

Later Life ◽

Future Research ◽

Psychotherapeutic Process ◽

Images Of Aging ◽

Client Communication

Both psychotherapists and their clients have mental representations of old age and the aging process. In this conceptual review, we draw on available research from gerontology, social and developmental psychology, and communication science to consider how these “images of aging” may affect the psychotherapeutic process with older clients. On the basis of selected empirical findings we hypothesize that such images may affect the pathways to psychotherapy in later life, therapist-client communication, client performance on diagnostic tests as well as how therapists select and apply a therapeutic method. We posit that interventions to help both older clients and therapists to reflect on their own images of aging may increase the likelihood of successful treatment. We conclude by making suggestions for future research.

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The Moving-IAT

European Journal of Psychological Assessment ◽

10.1027/1015-5759/a000305 ◽

2017 ◽

Vol 33 (6) ◽

pp. 445-452

Author(s):

Monika Fleischhauer

Keyword(s):

Internal Consistency ◽

Personality Assessment ◽

Block Structure ◽

Mental Representations ◽

Indirect Measures ◽

Attitude Research ◽

Self Reports ◽

Implicit Personality ◽

Single Block ◽

Psychometric Quality

Abstract. Accumulated evidence suggests that indirect measures such as the Implicit Association Test (IAT) provide an increment in personality assessment explaining behavioral variance over and above self-reports. Likewise, it has been shown that there are several unwanted sources of variance in personality IATs potentially reducing their psychometric quality. For example, there is evidence that individuals use imagery-based facilitation strategies while performing the IAT. That is, individuals actively create mental representations of their person that fit to the category combination in the respective block, but do not necessarily fit to their implicit personality self-concept. A single-block IAT variant proposed by attitude research, where compatible and incompatible trials are presented in one and the same block, may prevent individuals from using such facilitation strategies. Consequently, for the trait need for cognition (NFC), a new single-block IAT version was developed (called Moving-IAT) and tested against the standard IAT for differences in internal consistency and predictive validity in a sample of 126 participants. Although the Moving-IAT showed lower internal consistency, its predictive value for NFC-typical behavior was higher than that of the standard IAT. Given individual’s strategy reports, the single-block structure of the Moving-IAT indeed reduces the likelihood of imagery-based strategies.

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