Bootstrapping cognition from behavior-a computerized thought experiment

We show that simple perceptual competences can emerge from an internal simulation of action effects and are thus grounded in behavior. A simulated agent learns to distinguish between dead ends and corridors without the necessity to represent these concepts in the sensory domain. Initially, the agent is only endowed with a simple value system and the means to extract low-level features from an image. In the interaction with the environment, it acquires a visuo-tactile forward model that allows the agent to predict how the visual input is changing under its movements, and whether movements will lead to a collision. From short-term predictions based on the forward model, the agent learns an inverse model. The inverse model in turn produces suggestions about which actions should be simulated in long-term predictions, and long-term predictions eventually give rise to the perceptual ability.     

Predictors of subjective age before and after cataract surgery: conscientiousness makes a difference

This study contributes to research on subjective age by examining the interplay of felt age with health, functional limitations, and personality. Individuals undergoing cataract surgery (N=134; 38 to 92 years of age) provided data for an assessment period of 6 weeks surrounding their scheduled surgery. Conscientiousness and repeated measurements of health indicators, functional limitations, and felt age were included in the analyses. Results indicated that functional limitations may be more important to the construction of felt age than their underlying health-related causes. Moreover, conscientious participants felt younger before and after surgery. Their functional status was less dependent on health than the functional status of less conscientious participants. This moderator effect is discussed along with health-related pathways leading to felt age.     

Synchronizing movements with the metronome: nonlinear error correction and unstable periodic orbits.

The control of human hand movements is investigated in a simple synchronization task. We propose and analyze a stochastic model based on nonlinear error correction; a mechanism which implies the existence of unstable periodic orbits. This prediction is tested in an experiment with human subjects. We find that our experimental data are in good agreement with numerical simulations of our theoretical model. These results suggest that feedback control of the human motor systems shows nonlinear behavior.