Most domestic dogs (Canis lupus familiaris) prefer food to petting: population, context, and schedule effects in concurrent choice.

Researchers let family dogs pick between two options. One lever gave a piece of dry food. Another lever gave a quick pet from the owner. The team then made food harder to get. They stretched the time between food pellets. They watched how the dogs split their time.

The study used a single-case design. Each dog served as its own control. Sessions happened in a quiet room. No extra training was given. The only change was the food schedule.

When food came fast, dogs almost ignored petting. They stayed at the food lever. When the food schedule grew lean, the picture flipped. Dogs spent less time at the food lever. Some started visiting the owner for pets. The change was large enough to see by eye.

Lean food schedules also made behavior less predictable. One dog might take a quick pet then return to food. Another might sit for a long stroke. The exact pattern varied, but the trend was clear. Less easy food meant more social contact.

Fernandez et al. (2023) extends this idea to shelter dogs. They used an automated feeder that dropped food every minute. Kennel dogs moved more and barked less. Both studies show that timing of food, not just the food itself, drives behavior.

Older rat work sets the groundwork. Blackman (1970), Smith (1967), and Nelson et al. (1978) all found that longer gaps between food pellets create "schedule-induced" side behaviors. The dog study mirrors this: when food is scarce, dogs ramp up an alternate activity — seeking petting.

Locurto et al. (1980) adds a twist. They showed that schedule-induced drinking can actually reinforce lever pressing in rats. Likewise, the dogs’ petting time rose only when the food schedule was lean. The context of periodic feeding gives social contact its power.

You can use lean food schedules to boost social behavior in therapy animals or pets. If you want a dog to approach for praise, deliver kibble on a slow fixed-time schedule. The same rule may apply to kids who prefer edible reinforcers. Thin the edible rate and you might see more interest in social rewards like praise or high-fives. Start with a dense edible schedule, then gradually space it out while watching for new, desired responses.