Evidence that logical reasoning depends on conscious processing

Humans, unlike other animals, are equipped with a powerful brain that permits conscious awareness and reflection. A growing trend in psychological science has questioned the benefits of consciousness, however. Testing a hypothesis advanced by [Lieberman, M. D., Gaunt, R., Gilbert, D. T., & Trope, Y. (2002). Reflection and reflexion: A social cognitive neuroscience approach to attributional inference. Advances in Experimental Social Psychology, 34, 199-249], four studies suggested that the conscious, reflective processing system is vital for logical reasoning. Substantial decrements in logical reasoning were found when a cognitive load manipulation preoccupied conscious processing, while hampering the nonconscious system with consciously suppressed thoughts failed to impair reasoning (Experiment 1). Nonconscious activation (priming) of the idea of logical reasoning increased the activation of logic-relevant concepts, but failed to improve logical reasoning performance (Experiments 2a-2c) unless the logical conclusions were largely intuitive and thus not reliant on logical reasoning (Experiment 3). Meanwhile, stimulating the conscious goal of reasoning well led to improvements in reasoning performance (Experiment 4). These findings offer evidence that logical reasoning is aided by the conscious, reflective processing system.     

Understanding and Overcoming Self‐control Depletion

After people exert self‐control, self‐control performance on subsequent tasks tends to suffer, as if the capacity for self‐control was depleted by the prior exertion. The present paper discusses self‐control depletion and how people may overcome it. We searched the psychology literature and found nearly 40 empirical articles documenting diverse traits and strategies that counteract depletion, thereby facilitating self‐control success. The evidence points to two major strategies for overcoming depletion. The first strategy involves offsetting the high amount of effort required for self‐control (e.g., introducing a brief period of rest). The second involves compensating for the low immediate rewards that most self‐control tasks offer (e.g., providing an additional incentive for exerting self‐control). These strategies can be interpreted neatly within the framework of recent motivational accounts of self‐control depletion. This analysis may inform those aiming to improve self‐control success or simply to understand and anticipate when and why self‐control depletion occurs.     

Toward a physiology of dual-process reasoning and judgment: lemonade, willpower, and expensive rule-based analysis

This experiment used the attraction effect to test the hypothesis that ingestion of sugar can reduce reliance on intuitive, heuristic-based decision making. In the attraction effect, a difficult choice between two options is swayed by the presence of a seemingly irrelevant "decoy" option. We replicated this effect and the finding that the effect increases when people have depleted their mental resources performing a previous self-control task. Our hypothesis was based on the assumption that effortful processes require and consume relatively large amounts of glucose (brain fuel), and that this use of glucose is why people use heuristic strategies after exerting self-control. Before performing any tasks, some participants drank lemonade sweetened with sugar, which restores blood glucose, whereas others drank lemonade containing a sugar substitute. Only lemonade with sugar reduced the attraction effect. These results show one way in which the body (blood glucose) interacts with the mind (self-control and reliance on heuristics).     

Consider it done! Plan making can eliminate the cognitive effects of unfulfilled goals

Unfulfilled goals persist in the mind, as asserted by ample theory and evidence (e.g., the Zeigarnik effect). The standard assumption has been that such cognitive activation persists until the goal is fulfilled. However, we predicted that contributing to goal pursuit through plan making could satisfy the various cognitive processes that usually promote goal pursuit. In several studies, we activated unfulfilled goals and demonstrated persistent goal activation over time. Unfinished goals caused intrusive thoughts during an unrelated reading task (Studies 1 and 5B), high mental accessibility of goal-related words (Studies 2 and 3), and poor performance on an unrelated anagram task (Study 4). Allowing participants to formulate specific plans for their unfulfilled goals eliminated the various activation and interference effects. Reduction of the effects was mediated by the earnestness of participants' plans: Those who ultimately executed their plans were those who also exhibited no more intrusions (Study 4). Moreover, changes in goal-related emotions did not appear to be a necessary component of the observed cognitive effects (Studies 5A and 5B). Committing to a specific plan for a goal may therefore not only facilitate attainment of the goal but may also free cognitive resources for other pursuits. Once a plan is made, the drive to attain a goal is suspended--allowing goal-related cognitive activity to cease--and is resumed at the specified later time.     

Unfulfilled goals interfere with tasks that require executive functions

Even after one stops actively pursuing a goal, many mental processes remain focused on the goal (e.g., the Zeigarnik effect), potentially occupying limited attentional and working memory resources. Five studies examined whether the processes associated with unfulfilled goals would interfere with tasks that require the executive function, which has a limited focal capacity and can pursue only one goal at a time. In Studies  and , activating a goal nonconsciously and then manipulating unfulfillment caused impairments on later tasks requiring fluid intelligence (solving anagrams; Study 1) and impulse control (dieting; Study 2). Study 3 showed that impairments were specific to executive functioning tasks: an unfulfilled goal impaired performance on logic problems but not on a test of general knowledge (only the former requires executive functions). Study 4 found that the effect was moderated by individual differences; participants who reported a tendency to shift readily amongst their various pursuits showed no task interference. Study 5 found that returning to fulfill a previously frustrated goal eliminated the interference effect. These findings provide converging evidence that unfulfilled goals can interfere with later tasks, insofar as they require executive functions.