Electrophysiological evidence of the amodal representation of symmetry in extrastriate areas.

Extrastriate visual areas are strongly activated by image symmetry. Less is known about symmetry representation at object-level rather than image-level. Here we investigated electrophysiological responses to symmetry, generated by amodal completion of partially-occluded polygon shapes. We used a similar paradigm in four experiments (N = 112). A fully-visible abstract shape (either symmetric or asymmetric) was presented for 250 ms (t0). A large rectangle covered it entirely for 250 ms (t1) and then moved to one side to reveal one half of the shape hidden behind (t2, 1000 ms). Note that at t2 no symmetry could be extracted from retinal image information. In half of the trials the shape was the same as previously presented, in the other trials it was replaced by a novel shape. Participants matched shapes similarity (Exp. 1 and Exp. 2), or their colour (Exp. 3) or the orientation of a triangle superimposed to the shapes (Exp. 4). The fully-visible shapes (t0-t1) elicited automatic symmetry-specific ERP responses in all experiments. Importantly, there was an exposure-dependent symmetry-response to the occluded shapes that were recognised as previously seen (t2). Exp. 2 and Exp.4 confirmed this second ERP (t2) did not reflect a reinforcement of a residual carry-over response from t0. We conclude that the extrastriate symmetry-network can achieve amodal representation of symmetry from occluded objects that have been previously experienced as wholes.

Careless responding in crowdsourced alcohol research: A systematic review and meta-analysis of practices and prevalence.

Crowdsourcing-the process of using the internet to outsource research participation to "workers"-has considerable benefits, enabling research to be conducted quickly, efficiently, and responsively, diversifying participant recruitment, and allowing access to hard-to-reach samples. One of the biggest threats to this method of online data collection however is the prevalence of careless responders who can significantly affect data quality. The aims of this preregistered systematic review and meta-analysis were: (a) to examine the prevalence of screening for careless responding in crowdsourced alcohol-related studies; (b) to examine the pooled prevalence of careless responding; and (c) to identify any potential moderators of careless responding across studies. Our review identified 96 eligible studies (∼126,130 participants), of which 51 utilized at least one measure of careless responding, 53.2%, 95% CI [42.7%-63.3%]; ∼75,334 participants. Of these, 48 reported the number of participants identified by careless responding method(s) and the pooled prevalence rate was ∼11.7%, 95% CI [7.6%-16.5%]. Studies using the MTurk platform identified more careless responders compared to other platforms, and the number of careless response items was positively associated with prevalence rates. The most common measure of careless responding was an attention check question, followed by implausible response times. We suggest that researchers plan for such attrition when crowdsourcing participants and provide practical recommendations for handling and reporting careless responding in alcohol research. (PsycInfo Database Record (c) 2022 APA, all rights reserved).