On worms, mirror neurons and explaining human behavior

A key challenge for psychological theorizing is: At what level(s) should we look for the best explanations and predictions of human behavior? The dominant view is that potentially the best theories to explain behavior are found in neuroscience and biology. Therefore, we start from the perspective of these lower levels, and consider the prospects of developing theories based on those levels. We focus on C. elegans, a model organism whose entire neuronal connectome is mapped, and use it as a case study to highlight the difficulties in developing neuroscientific theories of cognition and behavior. We argue that the neuroscientific levels are not promising avenues for constructing explanatory or predictive psychological theories. This is due to the immense complexity and context-dependency of biological systems, even those as simple as C. elegans. In order to tackle this complexity, we need higher-level variables that capture stable features of these systems. For psychological theory development, this implies that we should focus on conceptual work and discovering robust phenomena, and take psychology and behavior as the starting points.