1,721,035 research outputs found
Judgments of genetic relatedness of children
No full textOur object was to estimate the information about genetic relatedness visually available from facial photographs of children. The stimuli were forty-eight pairs of photographs of children. In half of the pairs, the children were siblings; in the other half, the children were not. Forty-eight observers, in a signal-detection task, judged which pairs depicted siblings. There were three occlusion conditions: sixteen observers viewed full-face photographs of the children, sixteen viewed the same photographs with the eye regions of both children masked, and sixteen viewed the photographs with the mouth regions masked. For each occlusion condition, we converted the observers' performances into estimates of Shannon information, an alternative to signal-detection measures that require distributional assumptions. The maximum possible information conveyed per pair is 1 bit. The results for each occlusion condition were: 0.36 bit (full face), 0.47 bit (eyes masked), 0.63 bit (mouth masked). We find that observers can extract considerable information about genetic relatedness from photographs of children's faces. It is remarkable that observers were able to extract more information with parts of the face occluded than they could from full faces, as if the intact face masked the facial features relevant to the task
Where is kinship information in the child's face? Signal detection study finds no evidence for lateralization.
No full textPurpose. Dal Martello & Maloney (2006, JOV ) report signal detection experiments measuring the amount of kinship information in the upper and lower halves of children's faces. They found that the upper and lower halves each contained significant information about kinship with the upper half of the face containing considerably more than the lower. The information in the two halves was statistically independent.
Previous work has shown that information about age, attractiveness, gender, identity, expression and lip-reading tends to be left-right lateralized. We test whether this is the case for kinship.
Methods. Stimuli: 30 pairs of photographs, each photograph portraying a child's face with background removed. Half were of siblings, half, unrelated. The children's ages spanned 14 years. Observers: 124 adult observers who judged each pair as siblings or not. We summarized performance in each condition by signal detection estimates d′ and β. Conditions: Full Face visible (FF); Right Half visible (RH); Left Half visible (LH). Different observers participated in each condition.
Results. Performance in FF (d′ = 1.079) did not differ significantly (p = n.s.) from performance in RH condition (d′ = 1.024) or from performance in LH (d' = 1.004). Performance in RH and LH did not differ significantly (p = n.s.). The beta values of FF (β = 0.888) and RH (β = 0.896) did not differ (p = n.s.) and indicated an equal bias towards saying related. The beta for LH (β = 1.102) differed significantly (p = 0.0001) from betas on the other conditions.
Conclusion. Kinship cues appear to be evenly distributed across the vertical halves of the face and completely redundant. There is no superiority of one or the other side of the observed face for kinship. Observers have a bias against saying 'related' when the right half of the face is masked
Spontaneous patterns in the perceived direction of motion in ambiguous motion quartets: Effect of perception or judgment?
No full textIn a motion quartet (MQ), perceived direction of rotation is bistable, sometimes clockwise (C) sometimes counterclockwise (c). We reported (Martello et al, 2004 Journal of Vision 4 in press, abstract) that observers exhibited spontaneous patterns across time in their responses. Our results could be explained as completion of two kinds of patterns: (i) sequences (eg CCCC > C), and (ii) alternations (eg CcCc > C). We report an experiment intended to determine whether the effect of past perceptions is present even when the observer does not overtly judge the direction of MQs. We collected psychometric functions P(C|angle) for sixteen subjects who viewed almost 2000 MQ trials each. The trials were organised in groups of four (tetrads) and the angles in the MQs for the first three trials in each tetrad were chosen so that we could control the perceived direction of motion on these trials. The observer did not respond to these trials but simply observed them. On the fourth trial of each tetrad, the subject saw an MQ whose direction he judged. We found that the alternating sequences CcC and cCc still led to a strong bias to completion but that the effect of the cumulative sequences ccc and CCC had vanished
Kin recognition based on viewing photographs of children's faces is not affected by facial inversion.
No full textBackground: Many facial tasks such as identity recognition and judgments of emotion are more difficult when faces are inverted. We report an objective task (judgment of kinship of pairs of children) where task performance does not deteriorate with inversion of stimuli. Methods: 30 pairs of color photographs, each photograph portraying a frontal view of a child's face with background removed. Half of the pairs were siblings, half unrelated. The children's ages spanned 14 years. The distribution of age differences for related and unrelated pairs was matched as were gender differences. A total of 118 adult observers judged each pair as siblings or not. We summarized performance in each condition by signal detection d′ estimates. Conditions: Upright face (UF); face flipped around a horizontal axis (IF); 180° rotated face (RF). Different observers participated in each condition. Results: Performance in the UF condition (d′ = 1.058), IF condition (d′ =1.197), and RF condition (d′ = 1.048) were not significantly different (p > 0.05). Likelihood criterion (β) values of UF (β = 0.967), IF (β = 1.054), RF (β = 1.033) also did not differ significantly (p > 0.05). The β values of UF, IF and RF were not significantly different from 1 (p > 0.05): there was no significant bias in classifying children as related or unrelated. Conclusion: Allocentric kin recognition is not disrupted by inversion of the facial stimuli: the judgment appears to rely on inversion invariant cues. We discuss this result in conjunction with previous work (Dal Martello & Maloney, 2006; DeBruine et al., 2009) concerning localization of kin recognition cues in the face
Planning sequences of arm-hand movements to maximise expected gain
No full textWe examined how subjects plan movement sequences in a 'foraging' task involving three disks that appeared simultaneously at a small number of possible locations on a touch-screen monitor. Subjects received monetary rewards for the disks they touched within 1.6 s. Disk colour signaled the value. The subjects could choose to attempt three disks in any order and could choose to attempt fewer than three disks. The dependent variable was the estimated probability of hitting each disk ( pA, pB, pC) as a function of sequence. It might be (0.9, 0.6, 0.5) for sequence ABC but (0.9, 0, 0.9) for sequence AC (no attempt to hit B). The sequence ABC offers the higher probability of hitting all three disks but, if A and C are made valuable enough, the sequence AC has higher expected gain. We tested whether subjects planned movement sequences that maximised expected gain. The experiment consisted of three sessions. In the first session, ten naive subjects were trained until their performance was stable. In the second session, we measured how accurately each subject could execute each of the 12 possible sequences of length 2 or 3 on three disks of equal value. In the last session, the values of the disks were altered by amounts that varied between blocks of trials. Subjects were told the values of the colour-coded disks before each block and were free to choose any sequence. On the basis of second-session performance we could predict the strategy each subject should adopt on each trial in order to maximise expected value for each assignment of values to disks. Subjects did change strategies in the expected direction but typically favoured strategies that maximised probability of hitting three disks over the maximum expected gain strateg
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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