INTERRUPTING AN ASSESSMENT PROCESS TO PROBE CHANGES IN THE MOTIVATIONAL STATE

The ease of distraction of hermit crabs, Pagurus bernhardus, during shell investigation was examined in an attempt to probe changes in motivational state that are dependent upon the acquisition of information during an assessment process. The crabs recovered sooner from a startling stimulus if they were (1) approaching or manipulating a high quality shell or (2) occupying a poor quality shell. The startle response lasted longer when the novel stimulus was given at an early stage of investigation. The subsequent aperture investigation was longer when the novel stimulus occurred early in the shell assessment and was long when the startle response was long. These data are discussed with respect to information gathering and attentional and motivational change. © 1990 The Association for the Study of Animal Behaviour.