), 117 from the USA (30.3 ± 8.4 years, ranging from 18 to 68 years; 31 females), and 54 from Malaysia (20.9 ± 4.0 years, ranging from 17 to 36 years; 45 females)3. This study was reviewed and approved by the Central University Research Ethics Committee of the University of Oxford. All of the participants provided informed consent prior to taking part in the study. The Malaysian participants were recruited via email, which contained a link to the online experiment. The North American and Indian participants were recruited from Amazon’s Mechanical Turk, and took part in this study in exchange for a payment of 0.80 US dollars. Through a feature of Mechanical Turk, we specified that only people registered as living in America or India could take part in the study. The Chinese participants were undergraduate students from Tsinghua University, Beijing, China, and they received credit to fulfill the requirement of an introductory psychology course.
This study was conducted online using Adobe Flash-based Xperiment software (www.xperiment.mobi downloaded on 15/05/13). The participants from India, Malaysia, and the USA completed the task in English, whereas the participants from China did so in Chinese. The text descriptors and images used as stimuli were presented against a gray background (RGB: 217, 217, 217), and each stimulus was tightly fit within a 90 × 90 pixel box. Text descriptors of bitter, salty, sour, umami, and sweet were used for the five taste terms, all of which were in the Times New Roman font size 22.
Three types of images were used as the central targets, including the images of shapes, color patches (all presented as a square shape), and texture patches (all in the square shape). Specifically, 11 different color patches were used, including black (RGB: 0, 0, 0), blue (RGB: 0, 0, 255), brown (RGB: 165, 42, 42), green (RGB: 0, 255, 0), gray (RGB: 128, 128, 128), orange (RGB: 255, 165, 0), pink (RGB: 255, 192, 203), purple (RGB: 128, 0, 128), red (RGB: 255, 0, 0), white (RGB: 255, 255, 255), and yellow (RGB: 255, 255, 0). As shown in Figure 1, 15 different shapes were presented, all in black, including the arrow, asymmetrical star, blob, circle, cloud, cross, diamond, drop, ellipse, heart, moon, rectangle, square, star, and triangle. Similar to Woods et al.’s (2013) study, two texture patches were used, including both smooth and rough textures (see Figure 1 for an illustration). Specifically, the smooth texture was visualized as a gray background with sparse granular gray spots, whereas the rough texture was visualized by a gray background with dense granular white spots.
Design and Procedure
A within-participants experimental design was used. That is, all of the participants undertook a total of 28 experimental trials (15 shape trials, 11 color trials, and 2 texture trials) which were presented in a random order. At the beginning of the study, the participants were given instructions as to how to complete the study, and completed a single trial in which they were asked to match the taste word ‘umami’ with one of the following words: paper, purple, savory, sweet, watch, yellow. The experiment continued once the participant had correctly answered this question. Participants were directed to the Wikipedia website4 for the term “umami” in the case that they wanted a description of this term. The purpose of this practice trial was twofold, as it provided an opportunity for the participants to become familiar with both the click-drag-release task, and the meaning of the term “umami.” After this, the participants were instructed to complete each trial as quickly and as accurately as possible and to click ‘start’ to begin the study.
During each trial, a central target (e.g., an image of the cloud shape, as shown in Figure 2) was presented in the center of the screen, with words representing the five basic tastes arrayed in a pentagon-shape around it. The location of each taste word was varied randomly around the pentagon from trial to trial. The participant’s task involved dragging the target to the word that was associa