Investigating the implicit stereotypes of recycled construction and demolition waste products with an fNIRS-enabled single category implicit association test

Abstract

The construction industry makes a major contribution to the growth of cities and yet produces enormous waste. Construction and demolition wastes can be recycled and reused, but their products are still challenged by the market. Many researchers blame the negative stereotype of cycled products, however, people show supportive opinions on recycled products in questionnaires. This study designed a single-category implicit association test (SC-IAT) and deployed functional near-infrared spectroscopy (fNIRS) device for direct measurement. The SC-IAT response times, semantic survey scores, and fNIRS blood oxygen concentration were used to quantitatively reflect the implicit impression of the recycled products. The calibrated β value based on the general linear regression analysis and D-scores were used to capture the cognitive conflicts and assess the implicit stereotypes. After a predesigned experiment, a negative stereotype was observed based on the prolonged response time. The high HbO concentration level in the right dorsolateral prefrontal cortex and the frontal oculomotor area also suggests a cognitive conflict in the “positive words + self words” group. These outcomes demonstrate that fNIRS can supplement the SC-IAT and reveals the implicit cognitive attitudes toward recycled products.