Past visual experiences weigh in on body size estimation

Abstract

Body size is a salient marker of physical health, with extremes implicated in various mental and physical health issues. It is therefore important to understand the mechanisms of perception of body size of self and others. We report a novel technique we term the bodyline, based on the numberline technique in numerosity studies. One hundred and three young women judged the size of sequentially presented female body images by positioning a marker on a line, delineated with images of extreme sizes. Participants performed this task easily and well, with average standard deviations less than 6% of the total scale. Critically, judgments of size were biased towards the previously viewed body, demonstrating that serial dependencies occur in the judgment of body size. The magnitude of serial dependence was well predicted by a simple Kalman-filter ideal-observer model, suggesting that serial dependence occurs in an optimal, adaptive way to improve performance in size judgments.

Attraction to the recent past in aesthetic judgments: A positive serial dependence for rating artwork

“…Our findings add to previous studies suggesting that assimilative serial dependence occurs for higher level judgments such as face and body attractiveness (Alexi et al, 2018;Taubert, Van der Burg, et al, 2016;Xia et al, 2016), and extends the scope of assimilative serial dependences further into the domain of aesthetic judgments of artwork. It remains unanswered, however, at which stage of aesthetic judgment this positive bias occurs.…”

“…With one degree of freedom given to the magnitude of prediction (a scale factor K which weights the entire right-hand side of Equation 3), the scaled model gives an improved fit of R 2 ¼ 0.8 when K has a value of 0.67 (blue continuous line in Figure 3A). In line with previous serial dependence studies showing assimilative patterns (Alexi et al, 2018;Bliss, Sun, & D'Esposito, 2017;Fischer & Whitney, 2014;Fritsche et al, 2017), our finding suggests that aesthetic ratings are systematically biased towards information from the recent past.…”

“…The assimilative serial dependence observed in our results and reflected in the model was further supported when we fitted a linear regression to the four data points in the central part of the response-stimulus distance range (dotted line in Figure 3A). In this central range, the previous response is of comparable attractiveness to the current one, and the slope of this line provides an effective way to measure the magnitude of the bias (Alexi et al, 2018). The slope of the regression line was 0.1, which was tested for significance by 1000 iterations of a permutation test.…”

“…Assimilative serial dependence has been reported for a variety of basic sensory attributes, such as orientation, motion, and numerosity (Alais, Leung, & Van der Burg, 2017;Cicchini et al, 2014;Corbett, Fischer, & Whitney, 2011;Fischer & Whitney, 2014). This assimilation toward the recent past extends to processing higher level visual information such as body shape (Alexi et al, 2018), face gender, attractiveness, and expression (Hsu & Yang, 2013;Taubert, Alais, & Burr, 2016;Taubert, Van der Burg, & Alais, 2016;Xia, Leib, & Whitney, 2016) and preference for photographs (Chang, Kim, & Cho, 2017). Interestingly, evaluation Citation: Kim, S., Burr, D., & Alais, D. (2019).…”

The functional role of serial dependence

“…Two recent papers [ 2 , 3 ] introduced a new psychophysical paradigm, serial dependence , which provided direct evidence of how a system incorporates past information into the perception of the current stimulus. These effects have now been confirmed with a variety of stimuli and tasks, from simple orientation judgements [ 3 – 5 ], numerosity [ 2 ], position [ 6 , 7 ], facial identity and expression [ 8 , 9 ], eye gaze [ 10 ], pulchritude [ 11 ] or body size [ 12 ], to complex judgements such as summary statistics [ 13 ], variance [ 14 ] and confidence [ 15 ]. A series of control experiments showed that serial dependence effects could not be accounted for by effects such as priming, hysteresis, explicit memory or expectation.…”