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How category structure influences the perception of object similarity: the atypicality bias.

Tanaka JW, Kantner J, Bartlett M - Front Psychol (2012)

Bottom Line: If similarity judgments are guided purely by their physical properties, the morph should be perceived to be equally similar to its typical parent as its atypical parent.In this framework, atypical stimuli are located in a sparser region of the space where there is less competition for recognition and therefore, these representations capture a broader range of inputs.These results suggest that the perceived likeness of an object is influenced by the organization of surrounding exemplars in the category space.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Victoria Victoria, BC, Canada.

ABSTRACT
Why do some faces appear more similar than others? Beyond structural factors, we speculate that similarity is governed by the organization of faces located in a multi-dimensional face space. To test this hypothesis, we morphed a typical face with an atypical face. If similarity judgments are guided purely by their physical properties, the morph should be perceived to be equally similar to its typical parent as its atypical parent. However, contrary to the structural prediction, our results showed that the morph face was perceived to be more similar to the atypical face than the typical face. Our empirical studies show that the atypicality bias is not limited to faces, but extends to other object categories (birds) whose members share common shape properties. We also demonstrate atypicality bias is malleable and can change subject to category learning and experience. Collectively, the empirical evidence indicates that perceptions of face and object similarity are affected by the distribution of stimuli in a face or object space. In this framework, atypical stimuli are located in a sparser region of the space where there is less competition for recognition and therefore, these representations capture a broader range of inputs. In contrast, typical stimuli are located in a denser region of category space where there is increased competition for recognition and hence, these representation draw a more restricted range of face inputs. These results suggest that the perceived likeness of an object is influenced by the organization of surrounding exemplars in the category space.

No MeSH data available.


Related in: MedlinePlus

Diagram of the attractor field model. The atypical and typical representations of interest are depicted as filled gray circles. Located in a sparse sub-region of face space, the atypical face representation has a larger attractor field relative to the smaller attractor field of the typical representation situated in a denser sub-region. The morph vector is indicated by the dashed line connecting the atypical and typical parent face representations and morph representations are located along the vector. The 50/50 morph is located at the midpoint of the vector and is equal in its physical distance from its atypical and typical parent representations. The atypicality bias is the result of the 50/50 morph lying closer to attractor boundary of the atypical representation than the typical representation.
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Figure 4: Diagram of the attractor field model. The atypical and typical representations of interest are depicted as filled gray circles. Located in a sparse sub-region of face space, the atypical face representation has a larger attractor field relative to the smaller attractor field of the typical representation situated in a denser sub-region. The morph vector is indicated by the dashed line connecting the atypical and typical parent face representations and morph representations are located along the vector. The 50/50 morph is located at the midpoint of the vector and is equal in its physical distance from its atypical and typical parent representations. The atypicality bias is the result of the 50/50 morph lying closer to attractor boundary of the atypical representation than the typical representation.

Mentions: The attractor basins of visually similar faces are spatially close together in face space whereas faces that are distinct are far apart. The size of the attractor basin determines its influence on face space inputs. Face representations with relatively large attractor fields exert a broad influence on face space and have the potential to capture face inputs possess. Representations with smaller attractor fields have a more limited influence over face inputs. As shown in Figure 4, the Euclidean relationships between faces are preserved in the model where the morph face is shown as being equidistant from its typical and atypical parent faces. However, the atypicality bias is the result of the broader attractor field of the atypical face whose influence extends over a greater region of face space. Thus, a 50/50 morph that is situated between a typical and atypical parent face is more likely to fall into the basin of the atypical parent. As mentioned above, the attractor influence of the atypical parent extended to about 37/63% boundary in one of our experiments, suggesting a point of so-called subjective equality where a morph is equally likely to categorized as more similar to its typical parent or its atypical parent.


How category structure influences the perception of object similarity: the atypicality bias.

Tanaka JW, Kantner J, Bartlett M - Front Psychol (2012)

Diagram of the attractor field model. The atypical and typical representations of interest are depicted as filled gray circles. Located in a sparse sub-region of face space, the atypical face representation has a larger attractor field relative to the smaller attractor field of the typical representation situated in a denser sub-region. The morph vector is indicated by the dashed line connecting the atypical and typical parent face representations and morph representations are located along the vector. The 50/50 morph is located at the midpoint of the vector and is equal in its physical distance from its atypical and typical parent representations. The atypicality bias is the result of the 50/50 morph lying closer to attractor boundary of the atypical representation than the typical representation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3368386&req=5

Figure 4: Diagram of the attractor field model. The atypical and typical representations of interest are depicted as filled gray circles. Located in a sparse sub-region of face space, the atypical face representation has a larger attractor field relative to the smaller attractor field of the typical representation situated in a denser sub-region. The morph vector is indicated by the dashed line connecting the atypical and typical parent face representations and morph representations are located along the vector. The 50/50 morph is located at the midpoint of the vector and is equal in its physical distance from its atypical and typical parent representations. The atypicality bias is the result of the 50/50 morph lying closer to attractor boundary of the atypical representation than the typical representation.
Mentions: The attractor basins of visually similar faces are spatially close together in face space whereas faces that are distinct are far apart. The size of the attractor basin determines its influence on face space inputs. Face representations with relatively large attractor fields exert a broad influence on face space and have the potential to capture face inputs possess. Representations with smaller attractor fields have a more limited influence over face inputs. As shown in Figure 4, the Euclidean relationships between faces are preserved in the model where the morph face is shown as being equidistant from its typical and atypical parent faces. However, the atypicality bias is the result of the broader attractor field of the atypical face whose influence extends over a greater region of face space. Thus, a 50/50 morph that is situated between a typical and atypical parent face is more likely to fall into the basin of the atypical parent. As mentioned above, the attractor influence of the atypical parent extended to about 37/63% boundary in one of our experiments, suggesting a point of so-called subjective equality where a morph is equally likely to categorized as more similar to its typical parent or its atypical parent.

Bottom Line: If similarity judgments are guided purely by their physical properties, the morph should be perceived to be equally similar to its typical parent as its atypical parent.In this framework, atypical stimuli are located in a sparser region of the space where there is less competition for recognition and therefore, these representations capture a broader range of inputs.These results suggest that the perceived likeness of an object is influenced by the organization of surrounding exemplars in the category space.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Victoria Victoria, BC, Canada.

ABSTRACT
Why do some faces appear more similar than others? Beyond structural factors, we speculate that similarity is governed by the organization of faces located in a multi-dimensional face space. To test this hypothesis, we morphed a typical face with an atypical face. If similarity judgments are guided purely by their physical properties, the morph should be perceived to be equally similar to its typical parent as its atypical parent. However, contrary to the structural prediction, our results showed that the morph face was perceived to be more similar to the atypical face than the typical face. Our empirical studies show that the atypicality bias is not limited to faces, but extends to other object categories (birds) whose members share common shape properties. We also demonstrate atypicality bias is malleable and can change subject to category learning and experience. Collectively, the empirical evidence indicates that perceptions of face and object similarity are affected by the distribution of stimuli in a face or object space. In this framework, atypical stimuli are located in a sparser region of the space where there is less competition for recognition and therefore, these representations capture a broader range of inputs. In contrast, typical stimuli are located in a denser region of category space where there is increased competition for recognition and hence, these representation draw a more restricted range of face inputs. These results suggest that the perceived likeness of an object is influenced by the organization of surrounding exemplars in the category space.

No MeSH data available.


Related in: MedlinePlus