Fig. 2.

A Distribution of studies according to publication period (n = 100). B Word cloud of the 100 most mentioned keywords and terms in the included studies. The displayed font size of each term is indicative of the frequency of occurrence. C Number of studies per type of tested cue and setting of the experiment. Note: Two studies were placed in two categories each; therefore, 102 studies are summarized. D World map (created with mapchart.net) showing the geographical distribution of the field studies (n = 54). Note: One study was conducted in two countries; therefore, 55 study locations are listed.