Abstract
Daily activities often occur in familiar environments, allowing us to learn. Laboratory studies have shown that people readily acquire an implicit spatial preference for locations that frequently contained a search target in the past. These studies, however, have focused on group characteristics, downplaying the significance of individual differences. In a pre-registered study, we examined the stability of individual differences in two variants of an implicit location probability learning (LPL) task. We tested the possibility that individual differences were stable in variants that shared the same search process, but not in variants involving different search processes. To do so, we used a novel interleaved training design to induce LPL in two separate tasks: a spatial preference for one region in task 1, and a spatial preference for a second region in task 2. In Experiment 1, 104 participants performed alternating blocks of T-among-Ls and 5-among-2s search tasks. Unbeknownst to them, the search target appeared disproportionately often in one region of space; the high-probability “rich” quadrants differed between the two tasks. LPL transferred between the two tasks: search was faster when the target appeared in the current-rich (the rich quadrant of the currently trained task) and other-rich quadrant (the rich quadrant of the other task) than in the low-probability quadrants. Individuals who showed greater LPL in the T-task also did so in the 5-task and vice versa. In Experiment 2, participants searched for either a camouflaged-T against background noise or a well-segmented T among well-segmented Ls. These two tasks produced task-specific learning that did not transfer between tasks: LPL sped up RT toward the current-rich quadrant but not the other-rich quadrant. Moreover, individual differences in learning did not correlate between tasks. Thus, LPL is associated with stable individual differences across variants, but only when the variants share common search processes.