Memory and Intelligence
Measuring intelligence in non-humans is difficult, but measuring intelligence in invertebrates presents a whole set of new challenges. As more evidence of the intelligence of octopuses is gathered, researchers question why octopuses have intelligence. In studies of vertebrates and mammals, intelligence is usually higher in social animals and animals who have longer lifespans such as elephants and primate species (Mather 2006). However, the octopus is a solitary creature that experiences no parental care and lives for a maximum of three years. What then is the reason for intelligence?
Researchers believe that learning in octopuses is environment-dependent rather than social-dependent. For example, the pressure from predators has perhaps shaped the incredible camouflage and chromatophore system (Mather 2006). Jennifer Mather, a well-known cephalopod researcher, hypothesized that octopuses gained the ability to learn because of a necessity to evolve within a quickly changing environment (Krakauer 2011). Whatever the reason behind octopus intelligence, as new studies emerge, researchers are frequently surprised at the magnitude of learning capabilities possessed by these cephalopods.
Mather (2006) found that octopuses occupy a home range for approximately 10 days then will move on to find another home range. In addition to leaving their home range, Mather (2006) also noticed when octopuses forage they do not return to areas they have already where they have already searched for prey. These occurrences suggest octopuses use spatial memories to aid in survival and also relates to the previously stated hypothesis from Mather.
The vertical lobe is primarily where learning and memory acquisition occur (Wells 1965; Hochner et al 2003; Hochner 2010). Studies have found that while partial removal of the vertical lobe does not interfere with memory acquisition and retrieval, complete removal of the vertical lobe renders the octopus unable to create memories (Hochner et al 2003).
In one experiment, Hochner et al (2006) found that if a octopus observed a “demonstrator” octopus doing a task then was required to do the same task, they performed better than octopuses who had no demonstrator and the memory of the task requirements was stable for a longer duration of time.
A different experiment done by Boycott and Young (1955) used belongingness to test memory duration. The octopuses were shown a crab within a square, but when they attacked they received a shock. Some octopuses learned to avoid the crab in the square after one of two experiences; in fact some individuals began squirting jets of water at the crabs. The memory of the crab and shock lasted for an average of three days once the experimenters stopped showing the crab. While the full mechanisms of memory creation and storage are not fully understood, octopuses are recognized to have a sophisticated system that may allow them to have a greater chance of survival (Hochner 2010).
Researchers believe octopuses learn through trial and error learning. Through trial and error, juvenile octopuses found how to best drill through bivalve shells. Researchers noted there was flexibility in the bivalve-opening techniques that may indicate central decision-making (Mather 2008). Mather (2006) also found that there were several sequences of predator-escape behaviors octopuses could choose from depending on the circumstances suggesting assessment and decision-making abilities.
The use of tools has commonly become the benchmark for determining cognitive sophistication. With observations of octopuses carrying coconut shells, often for long distances, Finn et al (2009) claimed this was tool use (see YouTube video below). Carrying the shells was a cumbersome task, slowing the octopus down considerably and could not offer protection whilst being carried. Finn et al (2009) argued this showed tool use and the capability to plan ahead as the only benefit of the shell would be potential future deployment as a structure. With the many examples of memory and learning capabilities, it is easy to see why octopuses are considered to be the most intelligent invertebrates (Anderson et al 2010).
Researchers believe that learning in octopuses is environment-dependent rather than social-dependent. For example, the pressure from predators has perhaps shaped the incredible camouflage and chromatophore system (Mather 2006). Jennifer Mather, a well-known cephalopod researcher, hypothesized that octopuses gained the ability to learn because of a necessity to evolve within a quickly changing environment (Krakauer 2011). Whatever the reason behind octopus intelligence, as new studies emerge, researchers are frequently surprised at the magnitude of learning capabilities possessed by these cephalopods.
Mather (2006) found that octopuses occupy a home range for approximately 10 days then will move on to find another home range. In addition to leaving their home range, Mather (2006) also noticed when octopuses forage they do not return to areas they have already where they have already searched for prey. These occurrences suggest octopuses use spatial memories to aid in survival and also relates to the previously stated hypothesis from Mather.
The vertical lobe is primarily where learning and memory acquisition occur (Wells 1965; Hochner et al 2003; Hochner 2010). Studies have found that while partial removal of the vertical lobe does not interfere with memory acquisition and retrieval, complete removal of the vertical lobe renders the octopus unable to create memories (Hochner et al 2003).
In one experiment, Hochner et al (2006) found that if a octopus observed a “demonstrator” octopus doing a task then was required to do the same task, they performed better than octopuses who had no demonstrator and the memory of the task requirements was stable for a longer duration of time.
A different experiment done by Boycott and Young (1955) used belongingness to test memory duration. The octopuses were shown a crab within a square, but when they attacked they received a shock. Some octopuses learned to avoid the crab in the square after one of two experiences; in fact some individuals began squirting jets of water at the crabs. The memory of the crab and shock lasted for an average of three days once the experimenters stopped showing the crab. While the full mechanisms of memory creation and storage are not fully understood, octopuses are recognized to have a sophisticated system that may allow them to have a greater chance of survival (Hochner 2010).
Researchers believe octopuses learn through trial and error learning. Through trial and error, juvenile octopuses found how to best drill through bivalve shells. Researchers noted there was flexibility in the bivalve-opening techniques that may indicate central decision-making (Mather 2008). Mather (2006) also found that there were several sequences of predator-escape behaviors octopuses could choose from depending on the circumstances suggesting assessment and decision-making abilities.
The use of tools has commonly become the benchmark for determining cognitive sophistication. With observations of octopuses carrying coconut shells, often for long distances, Finn et al (2009) claimed this was tool use (see YouTube video below). Carrying the shells was a cumbersome task, slowing the octopus down considerably and could not offer protection whilst being carried. Finn et al (2009) argued this showed tool use and the capability to plan ahead as the only benefit of the shell would be potential future deployment as a structure. With the many examples of memory and learning capabilities, it is easy to see why octopuses are considered to be the most intelligent invertebrates (Anderson et al 2010).