TY - JOUR TI - Multiphasic value biases in fast-paced decisions AU - Corbett, Elaine A AU - Martinez-Rodriguez, L Alexandra AU - Judd, Cian AU - O'Connell, Redmond G AU - Kelly, Simon P A2 - Wyart, Valentin A2 - Frank, Michael J A2 - Schubert, Anna-Lena VL - 12 PY - 2023 DA - 2023/02/13 SP - e67711 C1 - eLife 2023;12:e67711 DO - 10.7554/eLife.67711 UR - https://doi.org/10.7554/eLife.67711 AB - Perceptual decisions are biased toward higher-value options when overall gains can be improved. When stimuli demand immediate reactions, the neurophysiological decision process dynamically evolves through distinct phases of growing anticipation, detection, and discrimination, but how value biases are exerted through these phases remains unknown. Here, by parsing motor preparation dynamics in human electrophysiology, we uncovered a multiphasic pattern of countervailing biases operating in speeded decisions. Anticipatory preparation of higher-value actions began earlier, conferring a ‘starting point’ advantage at stimulus onset, but the delayed preparation of lower-value actions was steeper, conferring a value-opposed buildup-rate bias. This, in turn, was countered by a transient deflection toward the higher-value action evoked by stimulus detection. A neurally-constrained process model featuring anticipatory urgency, biased detection, and accumulation of growing stimulus-discriminating evidence, successfully captured both behavior and motor preparation dynamics. Thus, an intricate interplay of distinct biasing mechanisms serves to prioritise time-constrained perceptual decisions. KW - decision making KW - sequential sampling models KW - electroencephalography JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -