Tropical Octopus Abdopus aculeatus Can Learn to Recognize Real and Virtual Symbolic Objects

Evaluation of Visual and Tactile Perception by Plain-Body Octopus (Callistoctopus aspilosomatis) of Prey-Like Objects

We investigated the characteristic features of perception in octopuses by examining multisensory information from an object simulating prey, which provided different visual and tactile stimuli. In experiments, we presented plain-body octopus with four kinds of models, namely, the Lifelike crab, the Embedded crab, the Translucent crab, and the Black cuboid. These models contain different amounts of visual and tactile information that a crab originally contains: the Lifelike crab resembles a crab both visually and tactilely, the Embedded crab resembles a crab visually but provides different tactile information, the Translucent crab provides tactile information of a crab but contains less visual information, and the Black cuboid lacks both visual and tactile information of a crab. Among these four models, octopuses contacted most with the Lifelike crab, which was similar to their behavior with a crab. Indeed, octopuses were fastest to contact the Lifelike crab and had the longest duration of contacting it among the four models. Octopuses contacted the Embedded crab more than the Translucent crab, both of which had contrasting visuo-tactile information compared to that of a crab. Quickness of octopuses to contact and duration of contact with the Embedded crab were more similar to those with the Lifelike crab than to those with the Translucent crab. Furthermore, octopuses contacted the Black cuboid least among the models. These results suggest that octopuses compositely detect both visual and tactile information in order to perceive an object. Furthermore, octopuses possess the potential priority either for visual or tactile information, by which they process the target object.

Comparative brain structure and visual processing in octopus from different habitats

Octopods are masters of camouflage and solve complex tasks, and their cognitive ability is said to approach that of some small mammals. Despite intense interest and some research progress, much of our knowledge of octopus neuroanatomy and its links to behavior and ecology comes from one coastal species, the European common octopus, Octopus vulgaris. Octopod species are found in habitats including complex coral reefs and the relatively featureless mid-water. There they encounter different selection pressures, may be nocturnal or diurnal, and are mostly solitary or partially social. How these different ecologies and behavioral differences influence the octopus central nervous system (CNS) remains largely unknown. Here we present a phylogenetically informed comparison between diurnal and nocturnal coastal and a deep-sea species using brain imaging techniques. This study shows that characteristic neuroanatomical changes are linked to their habits and habitats. Enlargement and division of the optic lobe as well as structural foldings and complexity in the underlying CNS are linked to behavioral adaptation (diurnal versus nocturnal; social versus solitary) and ecological niche (reef versus deep sea), but phylogeny may play a part also. The difference between solitary and social life is mirrored within the brain including the formation of multiple compartments (gyri) in the vertical lobe, which is likened to the vertebrate cortex. These findings continue the case for convergence between cephalopod and vertebrate brain structure and function. Notably, within the current push toward comparisons of cognitive abilities, often with unashamed anthropomorphism at their root, these findings provide a firm grounding from which to work.

Plain-Body Octopus's (Callistoctopus aspilosomatis) Learning about Objects via Both Visual and Tactile Sensory Inputs: A Pilot Study

Although various recognizing abilities have been revealed for octopuses, they predominantly deal with only a few species. Therefore, cognition diversity among other octopus species that have been overlooked needs to be investigated. We investigated whether plain-body octopus can learn a symbolic stimulus, for the reason that this octopus is abundant around Okinawa Island with a complex coral community landscape. Attention was paid to whether an octopus can learn a stimulus based solely on visual information without previous experience of learning it tactilely as well as visually. Furthermore, we examined whether different sensory inputs affect learning in octopuses. First, we tested whether octopuses can be conditioned to three different stimuli (object, picture, and video of a white cross). Octopuses that were presented an object or a picture could learn to touch them. However, octopuses that were presented a video could not learn to touch the stimulus. Second, we showed a video to octopuses that had already learned about an object or a picture to investigate whether the octopuses, having experienced a target using visual and tactile senses, can recognize a video of the target based solely on visual information. Octopuses could learn to touch the video. When a conditioned stimulus and a novel stimulus were simultaneously presented on a computer screen, an octopus that had learned an object more often selected the conditioned stimulus when compared with an octopus that had experienced only a picture. These findings suggest that octopuses use multisensory information to recognize a specific object.