Chimpanzee memory similar to human memory

New research from Aarhus University, Center on Autobiographical Memory Research, School of Business and Social Sciences challenges traditional beliefs that apes cannot remember events that have taken place more than 72 hours earlier.

2013.07.19 | Tine Bagger Christiansen

The author Marcel Proust has described how the unique taste of a piece of Petite Madeline (cake) dipped in a cup of tea spontaneously evoked a childhood memory of him visiting his aunt who always offered him a Madeleine dipped in tea. Do animals also have similar flashbacks?

This was the basis of an experiment, which now shows that given the proper clues, chimpanzees and orangutans can remember events in the past. This also means that their ability to remember bears many similarities to that of humans.

"We have conducted a new experiment which proves that chimpanzees and orangutans are able to remember the task of finding a tool in a particular place and using it correctly. The apes had only performed the task four times before three years earlier", says Postdoc Gema Martin-Ordas from Aarhus University, School of Business and Social Sciences.

Convincing results

The experiment was conducted among 15 chimpanzees and four orangutans. Out of the 11 apes in the experimental group, 10 were able to differentiate the task from other tasks of finding tools, which proves that apes are capable of linking relevant temporal and spacial components. None of the apes in the control group accomplished the task.

Three years prior to this experiment, the apes in the experimental group were introduced to a task: They watched a researcher hide two different kinds of tools (a long and a short stick) in two different places, and later they were to carry out the task of catching food they were unable to reach. The apes would be rewarded if they remembered the place where the useful tool was hidden, fetched the tool and used it.

To test whether the apes could remember a specific event in the past, the researchers conducted yet another experiment. The experiments were carried out in the exact same place, namely in the room where the apes sleep at night. Once again they were introduced to a task where they saw the relevant tool (this time a ball) being hidden and subsequently had to find it. When seeing the conductor of the experiment and the experimental set-up two weeks later, it turned out that the apes immediately knew where to find the right tool.

Apes and humans have much more in common that previously claimed

The complexity of the events the apes had to recall, fetching the tools so quickly and the long time that had passed since conducting the last experiment all indicates that chimpanzees and orangutans' recollection of previous events is similar to some of the functions of the human autobiographical memory.

"This means that apes and humans have even more in common than previously established. Most humans have what is called an autobiographical memory, i.e. the ability to recall events (through emotions and sensory perceptions) from our own lives. We know that humans often have spontaneous autobiographical memories when given specific clues, in the exact same way as the chimpanzees and orangutans in the experiment. This indicates that, evolutionarily speaking, this spontaneous part of human memory is very old", says Professor Dorthe Berntsen.

Facts

Postdoc Gema Martin-Ordas and Professor Dorthe Berntsen from Aarhus University, School of Business and Social Sciences, together with Prof. Joseph Call (MPI in Leipzig), have described the experiment, and as a result, their paper has been published in the acknowledged scientific journal Current Biology. 

Further information 

Dorthe Berntsen

Professor Dorthe Berntsen
Aarhus University, School of Business and Social Sciences
Center on Autobiographical Memory Research (CON AMORE)
Email: dorthe@psy.au.dk
Direct tel.: +45 87165868dorthe@psy.au.dk

Gema Martin-Ordas

Postdoc Gema Martin-Ordas
Aarhus University, School of Business and Social Sciences
Center on Autobiographical Memory Research (CON AMORE)
Email: ordas@psy.au.dk
Direct tel.: +45 87 16 54 69

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