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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

Example of the continuum of morph faces produced by image averaging a typical and atypical face pair. Morph faces in the continuum were produced in 5% intervals ranging from 35% contribution from the atypical (typical) parent to 65%.
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Figure 3: Example of the continuum of morph faces produced by image averaging a typical and atypical face pair. Morph faces in the continuum were produced in 5% intervals ranging from 35% contribution from the atypical (typical) parent to 65%.

Mentions: In the attractor field model, the attractor basin surrounding each stimulus is demarcated by a boundary signifying a point in similarity space at which a stimulus input will activate either of two representations with equal probability. The disparity in the similarities of the morph to its typical and atypical parents suggests that the boundary between the parents is not located at their midpoint. Where, then, does the boundary or point of subjective equality (PSE) between a typical and an atypical exemplar lie? Tanaka et al., 1998, Experiment 4) explored this issue by creating morphs with unequal contributions from the typical and atypical parent (e.g., 55% typical, 45% atypical, 60/40%, 65/35%; see Figure 3). The combination at which a morph is judged equally similar to the typical and atypical parent provides an indication of the relative distance of the attractor boundary from each parent. Interpolating from the atypicality bias observed in the various morph combination conditions, Tanaka et al. (1998) concluded that a morph containing a 63% contribution from its typical parent and a 37% contribution from its atypical parent is the PSE where the morph is perceived to bear equal resemblance to both parents. This outcome suggests a boundary at roughly two-thirds of the distance between the atypical and the typical parent for the face stimuli used by Tanaka and colleagues.


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

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

Example of the continuum of morph faces produced by image averaging a typical and atypical face pair. Morph faces in the continuum were produced in 5% intervals ranging from 35% contribution from the atypical (typical) parent to 65%.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Example of the continuum of morph faces produced by image averaging a typical and atypical face pair. Morph faces in the continuum were produced in 5% intervals ranging from 35% contribution from the atypical (typical) parent to 65%.
Mentions: In the attractor field model, the attractor basin surrounding each stimulus is demarcated by a boundary signifying a point in similarity space at which a stimulus input will activate either of two representations with equal probability. The disparity in the similarities of the morph to its typical and atypical parents suggests that the boundary between the parents is not located at their midpoint. Where, then, does the boundary or point of subjective equality (PSE) between a typical and an atypical exemplar lie? Tanaka et al., 1998, Experiment 4) explored this issue by creating morphs with unequal contributions from the typical and atypical parent (e.g., 55% typical, 45% atypical, 60/40%, 65/35%; see Figure 3). The combination at which a morph is judged equally similar to the typical and atypical parent provides an indication of the relative distance of the attractor boundary from each parent. Interpolating from the atypicality bias observed in the various morph combination conditions, Tanaka et al. (1998) concluded that a morph containing a 63% contribution from its typical parent and a 37% contribution from its atypical parent is the PSE where the morph is perceived to bear equal resemblance to both parents. This outcome suggests a boundary at roughly two-thirds of the distance between the atypical and the typical parent for the face stimuli used by Tanaka and colleagues.

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