

Egocentric distance cues and focal length were constant across room widths, highlighting the role of environmental context in judging distances in natural scenes. We found large and reliable effects of room width: Average judgments for the farthest targets in a 40-meter-wide room were between 16–33% larger than for the same target distances seen in a 1.5-meter-wide hallway.

Targets were placed at distances of 2–37 meters in rendered rooms that varied in width (1.5–40 meters) and depth (6–40 meters). In 4 experiments involving 452 participants, we investigated the effect of room width and depth on egocentric distance judgments. Here, we used rendered scenes and crowdsourced data collection to address these challenges. The cue bases for such effects remain unclear and are difficult to study systematically in real-world settings, given the challenges in manipulating large environmental features reliably and efficiently. Past work has suggested that perception of object distances in natural scenes depends on the environmental surroundings, even when the physical object distance remains constant. The results are discussed in terms of the emerging literature indicating that the internal representation of the body is dynamic and flexible. These distortions lasted throughout testing and did not fully return back to normal within 18 min. Altered visual feedback caused changes in participants' judgements of their body size: adapting to a wider body resulted in size overestimation whereas underestimations occurred after adapting to a narrower body. The accuracy of the representation was assessed at 6, 12 and 18 min following exposure to adaptation. Accuracy was measured using our novel psychophysical method that taps into the implicit body representation. Participants were exposed for five minutes to a distorted life-size image of themselves that was either 20% wider or 20% narrower than their normal size. In this study, visual adaptation was used to investigate whether exposure to distorted visual feedback alters the representation of body size and how long any such effects might last. However, it is not yet clear how body size perception may be affected when the internal body representation is manipulated. Inaccurate perceptions, such as under- or over-estimation of body size are often found in clinical eating disorder populations but have recently been shown also in healthy people.
