An artificial intelligence can accurately predict how a monkey plays the Pac-Man video game and mimic the animals鈥� eye movements when they do this.
at the Chinese Academy of Sciences and his colleagues trained two rhesus monkeys to play Pac-Man by rewarding them with juice for collecting all the dots in a maze and evading capture by ghosts. Getting Pac-Man, the character players control, to eat the ghosts after chomping on a special dot that makes them vulnerable also earned the monkeys a reward. As they played the game 35 times in total, the two monkeys鈥� eye movements were tracked.
Then the researchers trained a type of brain-like AI known as a neural network to predict the monkeys鈥� directional choices at maze junctions. The specific type of neural network they used, called a transformer network, has a self-attention mechanism that allows it to prioritise the most relevant information it encounters and act on it. Wang wondered if this attention mechanism would echo what was going on in an actual brain.
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The AI鈥檚 attention mechanism seemed to mimic what the monkeys were looking at, including focusing on where to move next, several moves in the distance 鈥� suggesting some element of the AI model was pre-planning its strategy.
Overall, the AI model was able to accurately predict the monkey鈥檚 choice of next move when Pac-Man reached a junction in the maze 87.6 per cent of the time. 鈥淲e showed that indeed this transformer structure may do something similar to the brain,鈥� says Yang.
AI models are often considered a 鈥渂lack box鈥� whose inner workings are hard to discern. However, the researchers were able to distinguish two different ways the artificial neurons within the neural network processed the information it encountered. One layer of the neural network focused on sending Pac-Man on a route that gained the player the highest rewards, while a second layer took a more strategic view, analysing how Pac-Man interacted with other objects in the maze.
While it can be risky to anthropomorphise AIs, the research does indicate that they might be able to 鈥渢hink鈥� or 鈥渓ook鈥� in a similar way to mammals, says at Bentley University in Massachusetts, who wasn鈥檛 involved in the study. 鈥淲hen tasked with predicting the monkey鈥檚 choices in the game, the AI evidently 鈥榣ooks鈥� at the various options on the screen in a similar way that the monkey does.鈥�
鈥淎dmittedly monkeys playing Pac-Man is a limited and even somewhat humorous setting, but the research shows a promising avenue that we鈥檒l likely see more of in the near future and that may bear fruit,鈥� says Giansiracusa.
arXiv
