In this paper we seek to gain an improved understanding of the structure of cognitive biases and their relationship with measures of intelligence and relevant non-cognitive constructs. We report on the outcomes of a study based on a heterogeneous set of seven cognitive biases — anchoring effect, belief bias, overconfidence bias, hindsight bias, base rate neglect, outcome bias and sunk cost effect. New scales for the assessment of these biases were administered to 243 undergraduate students along with measures of fluid (Gf) and crystallized (Gc) intelligence, a Cognitive Reflection Test (CRT), Openness/Intellect (O/I) scale and Need for Cognition (NFC) scale. The expected experimental results were confirmed — i.e., each normatively irrelevant variable significantly influenced participants' responses. Also, with the exception of hindsight bias, all cognitive biases showed satisfactory reliability estimates (αs > .70). However, correlations among the cognitive bias measures were low (rs < .20). Although exploratory factor analysis produced two factors, their robustness was doubtful. Cognitive bias measures were also relatively independent (rs < .25) from the Gf, Gc, CRT, O/I and NFC and they define separate latent factors. This pattern of results suggests that a major part of the reliable variance of cognitive bias tasks is unique, and implies that a one-factor model of rational behavior is not plausible.