ABSTRACT
TRACS (Tool for Research on Adaptive Cognitive Strategies) is a family of games played with a special deck of two-sided cards (see www.tracsgame.com). TRACS has the advantage of being both mathematically tractable to theoretical analysis and psychologically relevant to practical applications. The simplest game, called Straight TRACS, is a series of choices where the player must turn over one of two cards to match a third card. The object is to make the most matches on a trip through the deck. The challenge is to track the changing odds in order to make the best choices. We performed experiments and simulations to measure human performance in this probabilistic and dynamic task. We present our finding of a Baseline Bias, in which subjective odds are (incorrectly) anchored to the baseline odds. This is an interesting result because it is contrary to other well-known biases, such as Gambler’s Fallacy, in which subjective odds are (incorrectly) not anchored to the baseline odds. We propose a theory of mental models to reconcile our finding with previous research on heuristics and biases.
