Much research in the last two decades has demonstrated that human responses deviate from the performance deemed normative according to various models of decision making and rational judgment (e.g., the basic axioms of utility theory). This gap between the normative and the descriptive can be interpreted as indicating systematic irrationalities in human cognition. However, four alternative interpretations preserve the assumption that human behavior and cognition is largely rational. These posit that the gap is due to (1) performance errors, (2) computational (...) limitations, (3) the wrong norm being applied by the experimenter, and (4) a different construal of the task by the subject. In the debates about the viability of these alternative explanations, attention has been focused too narrowly on the modal response. In a series of experiments involving most of the classic tasks in the heuristics and biases literature, we have examined the implications of individual differences in performance for each of the four explanations of the normative/descriptive gap. Performance errors are a minor factor in the gap; computational limitations underlie non-normative responding on several tasks, particularly those that involve some type of cognitive decontextualization. Unexpected patterns of covariance can suggest when the wrong norm is being applied to a task or when an alternative construal of the task should be considered appropriate. Key Words: biases; descriptive models; heuristics; individual differences; normative models; rationality; reasoning. (shrink)

In two experiments subjects attempted to identify words presented below the objective threshold using two task strategies emphasizing either allowing a word to pop into their heads or looking carefully at the stimulus field . Words were selected to represent both meaningful and structural dimensions. We also asked subjects to indicate their strategy preference and to rate their motivation to perform well. In the absence of conscious perception, both strategy preference and word meaning interacted with strategy condition, mediating the accuracy (...) of subjects′ direct word identification judgments. Motivation also mediated performance. Word structure had no effect. Unconscious perception manifested only in the pop condition, underscoring the importance of task strategy in determining whether subliminal effects are observed. A follow-up control experiment using sham flashes demonstrated that strategy preference and motivation effects were not artifacts resulting from performance feedback cues. (shrink)

Van Selst and Merikle argued that the critical Preference × Strategy interaction findings could be alternatively explained by positing individual differences as a function of preference and strategy. They further argued that ruling out conscious perception depends on making the exhaustiveness assumption. We argue that the inhibitory effects satisfy objective threshold criteria regardless of possible individual differences in thresholds. We further suggest that the inhibitory findings are inherently incompatible with the conscious perception explanation and that therefore we do not need (...) to make the exhaustiveness assumption. We thus stand by our original conclusion that subliminal perception at the objective threshold has been demonstrated. (shrink)

The present study applies a new method for investigating dynamic unconscious processes. The method consists of selection of words from patient interview and test protocols that in the clinicians' judgments capture the patients' conscious symptom experience and the hypothetical unconscious conflict related to the symptom, subliminal and supraliminal presentation of these words, signal analysis of event-related potentials obtained to the word presentations. Eight phobics and three patients suffering from pathological grief reactions served as subjects. A time-frequency ERP analysis revealed that (...) subjects' ERPs classified the unconscious conflict words better subliminally than supraliminally, while the reverse was true for the conscious symptom words = 2.82, p = .011). The relationship between frequency and latency revealed a similar mirror image pattern for the unconscious conflict and conscious symptom words . This method demonstrated that objective, brain-based evidence for unconscious conflict can be obtained. (shrink)

In previous research Libet discovered that a critical time period for neural activation is necessary in order for a stimulus to become conscious. This necessary time period varies from subject to subject. In this current study, six subjects for whom the time for neural activation of consciousness had been previously determined were administered a battery of psychological tests on the basis of which ratings were made of degree of repressiveness. As hypothesized, repressive subjects had a longer critical time period for (...) neural activation of consciousness, suggesting the possibility that this neurophysiological time factor is a necessary condition for the development of repression. (shrink)

In previous research Libet discovered that a critical time period for neural activation is necessary in order for a stimulus to become conscious. This necessary time period varies from subject to subject. In this current study, six subjects for whom the time for neural activation of consciousness had been previously determined were administered a battery of psychological tests on the basis of which ratings were made of degree of repressiveness. As hypothesized, repressive subjects had a longer critical time period for (...) neural activation of consciousness, suggesting the possibility that this neurophysiological time factor is a necessary condition for the development of repression. (shrink)

This study is a philosophical critique of the foundations of Sigmund Freud's psychoanalysis. As such, it also takes cognizance of his claim that psychoanalysis has the credentials of a natural science. It shows that the reasoning on which Freud rested the major hypotheses of his edifice was fundamentally flawed, even if the probity of the clinical observations he adduced were not in question. Moreover, far from deserving to be taken at face value, clinical data from the psychoanalytic treatment setting are (...) themselves epistemically quite suspect. (shrink)

In this commentary on Stanovich & West (S&W) we call attention to two points: (1) Freud's original dual process theory, which antedates others by some seventy-five years, deserves inclusion in any consideration of dual process theories. His concepts of primary and secondary processes (Systems 1 and 2, respectively) anticipate significant aspects of current dual process theories and provide an explanation for many of their characteristics. (2) System 1 is neither rational nor irrational, but instead a-rational. Nevertheless, both the a-rational System (...) 1 and the rational System 2 can each have different roles in enhancing evolutionary fitness. Lastly, System 1 operations are incorrectly deemed “rational” whenever they increase evolutionary fitness. (shrink)