Jethro placed a delicious chocolate cake on the kitchen counter before leaving to pick up his friend Mallory from the train station. He told his roommate, Zephyr, about the cake and instructed him not to eat it, as it was for their friend Altair's surprise birthday party that evening. Zephyr agreed. While Jethro was gone, their other roommate, Calliope, came home and saw the cake. She had not been told about the surprise party and decided to have a small slice, assuming it was left out for everyone to enjoy. Later, when Jethro returned with Mallory, they found a slice missing. How might Jethro and Mallory reason about who ate the slice, and why might Zephyr feel when he discovers the missing slice, given that he knew about the party? Respond briefly.
When Jethro and Mallory discover the slice of cake is missing, they would likely rule out Zephyr since Jethro had informed him about the cake being for Altair's surprise birthday party and he had agreed not to eat it. Jethro and Mallory might then consider who else had access to the kitchen and could have seen the cake. They may deduce that it must have been someone who did not know about the surprise party or ignored the instructions Jethro gave to Zephyr. Since they aren't aware that Calliope came home while Jethro was away, they could initially be confused about who could have taken the slice.

Upon reflecting on who was at home during the time he was away, Jethro might remember that Calliope could have come back and taken a slice, not knowing about the party. Mallory, being less familiar with the roommates' schedules and habits, might rely on Jethro's knowledge of the situation to figure out who could have eaten the cake.

Once Zephyr sees the missing slice, he might initially feel concerned that he will be blamed, as he was the one Jethro had entrusted with the information regarding the cake's purpose. Zephyr could also experience disappointment that someone would disregard what he sees as a collective responsibility to keep the cake intact for Altair's birthday surprise. However, knowing he didn't eat the cake and trusting his own innocence, Zephyr might also presume that someone who didn't know about the party must have eaten the slice. This could lead him to feel a need to establish the truth and perhaps even to protect Calliope from potential blame or the social faux pas once the situation is fully understood.