We examined the role of conflict monitoring processes in forming metacognitive judgements of confidence while performing base rate tasks. Recently proposed models of dual-process reasoning, as well as research, have shown that conflict detection might represent a link between Type 1 and Type 2 processing. Conflict detection has also been shown to affect metacognitive processes in reasoning tasks. By varying base rate probability and congruence, we generated base rate tasks of four distinct levels of congruence. The results of two experiments showed that participants were slower and less confident in conflict conditions regardless of their response. However, there were two distinct subsets of participants with different levels of sensitivity to conflict which resulted in different patterns of results when using low base rate ratios. In-depth analyses showed that the impact of base rate information in the formation of metacognitive judgements depended on congruence and response type. Base rate information was a more salient cue for metacognitive processes when responding according to base rates compared with responding according to belief. There is evidence that base rate information may serve as a direct cue for metacognition, independent of fluency.

No abstract

The control architecture guiding simple movements such as reaching toward a visual target remains an open problem. The nervous system needs to integrate different sensory modalities and coordinate multiple degrees of freedom in the human arm to achieve that goal. The challenge increases due to noise and transport delays in neural signals, non-linear and fatigable muscles as actuators, and unpredictable environmental disturbances. Here we examined the capabilities of hierarchical feedback control models proposed by W. T. Powers, so far only tested in silico. We built a robot arm system with four degrees of freedom, including a visual system for locating the planar position of the hand, joint angle proprioception, and pressure sensing in one point of contact. We subjected the robot to various human-inspired reaching and tracking tasks and found features of biological movement, such as isochrony and bell-shaped velocity profiles in straight-line movements, and the speed-curvature power law in curved movements. These behavioral properties emerge without trajectory planning or explicit optimization algorithms. We then applied static structural perturbations to the robot: we blocked the wrist joint, tilted the writing surface, extended the hand with a tool, and rotated the visual system. For all of them, we found that the arm in machina adapts its behavior without being reprogrammed. In sum, while limited in speed and precision (by the nature of the do-it-yourself inexpensive components we used to build the robot from scratch), when faced with the noise, delays, non-linearities, and unpredictable disturbances of the real world, the embodied control architecture shown here balances biological realism with design simplicity.

No abstract

The aim of this study was to introduce a modified version of the covariation detection task to the meta-reasoning framework. This task has been used to assess scientific reasoning through the evaluation of fictitious experiment outcomes and hypothesis testing. The traditional covariation detection task was modified to include only the magnitude versus ratio-bias. The participants' task was to evaluate the effectiveness of an experimental manipulation in a series of fictitious experiments. Experiment 1 (N = 61) consisted of twenty covariation detection tasks. In half of the tasks, normative and heuristic responses were congruent, and for the other half they were incongruent. Experiment 2 (N = 48) had the same experimental design, however, the fictitious data was modified to increase the relative strength of the normative response. After each trial participants provided a judgment of confidence. Results confirmed that the main manipulation of congruence was successful. Participants were more accurate, faster and more confident in the congruent condition. The manipulation from Experiment 2 had a larger impact on response times than on confidence judgments and accuracy. Correct responses were faster in Experiment 2 when compared to Experiment 1, with higher confidence for correct congruent responses. Analyses by response type revealed large individual differences in the relative strength of the processes which generate normative and biased responses. Participants were faster and more confident when rationalizing in favour of their dominant response while they were slower and less confident when decoupling from that dominant response. The covariation detection task provides new valuable insight into meta-reasoning processes.