The passage below is accompanied by a set of questions. Choose the best answer to each question.

Cuttlefish are full of personality, as behavioral ecologist Alexandra Schnell found out while researching the cephalopod’s potential to display self-control. . . . “Self-control is thought to be the cornerstone of intelligence, as it is an important prerequisite for complex decision-making and planning for the future,” says Schnell . . .

[Schnell’s] study used a modified version of the “marshmallow test” . . . During the original marshmallow test, psychologist Walter Mischel presented children between age four and six with one marshmallow. He told them that if they waited 15 minutes and didn’t eat it, he would give them a second marshmallow. A long-term follow-up study showed that the children who waited for the second marshmallow had more success later in life. . . . The cuttlefish version of the experiment looked a lot different. The researchers worked with six cuttlefish under nine months old and presented them with seafood instead of sweets. (Preliminary experiments showed that cuttlefishes’ favorite food is live grass shrimp, while raw prawns are so-so and Asian shore crab is nearly unacceptable.) Since the researchers couldn’t explain to the cuttlefish that they would need to wait for their shrimp, they trained them to recognize certain shapes that indicated when a food item would become available. The symbols were pasted on transparent drawers so that the cuttlefish could see the food that was stored inside. One drawer, labeled with a circle to mean “immediate,” held raw king prawn. Another drawer, labeled with a triangle to mean “delayed,” held live grass shrimp. During a control experiment, square labels meant “never.”

“If their self-control is flexible and I hadn’t just trained them to wait in any context, you would expect the cuttlefish to take the immediate reward [in the control], even if it’s their second preference,” says Schnell . . . and that’s what they did. That showed the researchers that cuttlefish wouldn’t reject the prawns if it was the only food available. In the experimental trials, the cuttlefish didn’t jump on the prawns if the live grass shrimp were labeled with a triangle—many waited for the shrimp drawer to open up. Each time the cuttlefish showed it could wait, the researchers tacked another ten seconds on to the next round of waiting before releasing the shrimp. The longest that a cuttlefish waited was 130 seconds.

Schnell [says] that the cuttlefish usually sat at the bottom of the tank and looked at the two food items while they waited, but sometimes, they would turn away from the king prawn “as if to distract themselves from the temptation of the immediate reward.” In past studies, humans, chimpanzees, parrots and dogs also tried to distract themselves while waiting for a reward.

Not every species can use self-control, but most of the animals that can share another trait in common: long, social lives. Cuttlefish, on the other hand, are solitary creatures that don’t form relationships even with mates or young. . . . “We don’t know if living in a social group is important for complex cognition unless we also show those abilities are lacking in less social species,” says . . . comparative psychologist Jennifer Vonk.

A real point of difference must be stated or clearly shown by the passage for both tests.

Longer time span: children waited 15 minutes, while the longest cuttlefish wait was 130 seconds. A real difference.

Verbal versus symbolic communication: Mischel told the children the rule, while the researchers “couldn’t explain to the cuttlefish” and trained them to read circle, triangle and square labels. A real difference.

Human versus cuttlefish subjects: children aged four to six versus six young cuttlefish. A real difference.

Self-control and future success versus survival advantages: the original test’s follow-up did link waiting with later success, but the passage never says the cuttlefish study linked self-control with survival. It ties self-control to intelligence and planning, so this half of the contrast is unsupported and it is not a point of difference.

Hence, the former correlated self-control and future success, while the latter correlated self-control and survival advantages.

In the study, self-control means passing up an immediately available, less-preferred food to wait for a preferred one that arrives later. Preference order: live grass shrimp first, raw prawn next, Asian shore crab barely acceptable. A triangle means “delayed”, a square means “never”.

Asian shore crabs and raw prawns released at once, with live grass shrimp in a triangle drawer opening after one minute: waiting here means ignoring two available foods for the favourite food that will come. This shows self-control.

Live grass shrimp released while prawn drawers wait: the favourite food is already free, so eating it needs no restraint. Raw prawns released while a triangle drawer holds Asian shore crab: the delayed food is worse, so taking the prawns now is simple preference, and waiting would make no sense. Raw prawns released while a square drawer holds shrimp: square means “never”, so the shrimp will not come and taking the prawns is the expected choice, as in the control trials.

Hence, Asian shore crabs and raw prawns are simultaneously released while a live grass shrimp drawer labelled with a triangle is placed in front of the cuttlefish, to be opened after one minute.

Each statement must be checked against what the experiment shows.

Self-control helped by diversions: the cuttlefish sometimes turned away from the king prawn “as if to distract themselves from the temptation”. Inferable.

Self-control like human children: the cuttlefish, like the children, gave up an immediate reward to wait for a better one. Inferable.

Choice about food: preliminary tests showed a clear ranking (live grass shrimp, then raw prawn, then Asian shore crab), and the animals chose to wait for the preferred item. Inferable.

Intelligence impossible without sociability: the passage notes that most self-controlled animals are social, but cuttlefish are solitary and still showed self-control, and Vonk says we do not yet know whether social living matters for complex cognition. The experiment points away from this claim, so it cannot be inferred.

Hence, Intelligence in a species is impossible without sociability.

The passage ends with a wider pattern: most animals that can use self-control “share another trait in common: long, social lives”. Cuttlefish are noted as solitary, and Vonk adds that the role of social living in complex cognition is still unknown.

If cuttlefish lived in big groups that exhibit sociability, the self-control found in the experiment would sit squarely within that pattern linking self-control with social life. The new fact would fit with and round out the findings, so it complements them.

Equal fondness for live grass shrimp and raw prawn would remove the reason to wait and undercut the experiment. Inability to tell shapes apart would undermine the method, since the circle and triangle labels carried the timing. Waiting longer than 100 seconds only repeats what is already reported (the longest wait was 130 seconds) and adds nothing new.

Hence, Cuttlefish live in big groups that exhibit sociability.