Abstract

Kammerer and Frankish (this issue) suggest we evaluate introspection of mental states to examine consciousness, but in cephalopods we can only judge internal actions by behaviour output. We can look for mental states — perceptions, beliefs, and intentions — where the tight input–action linkage that is true for reflexes, instincts, and well-learned actions is discontinuous. Here the animal is internally evaluating the sensory input from previous information and making a decision before acting. Perceptions: the octopus motion parallax head bob and wound tending. Beliefs: the cuttlefish delay of gratification. Intentions: use of previous information for future strategies in octopus win-switch foraging and carrying a coconut for future shelter. Intentions are also used in skin displays, their widespread directional lateralization, the octopus 'passing cloud' to startle an immobile prey, the cuttlefish eyespot dot production to repel only visual predators, and the cuttlefish males' deceptive use of the female skin display. These examples allow us to assume in what situations introspection might be used but tell us little about the process of these actions. However, the quantitative variation, laterality, and combination of different displays suggest that cephalopod sexual skin displays are a special case of linkage of internal evaluation to external output that needs further behavioural and neurophysiological assessment.