Effects of predictability and competition on group and individual choice in a free-ranging foraging environment.

Lavinia and colleagues let rats forage in a big lab enclosure. Some rats worked alone. Others worked in groups of six.

The team set two food patches. They changed the grain ratio every session. Sometimes the ratio stayed the same all day (predictable). Sometimes it flipped without warning (unpredictable).

Both single rats and groups picked the richer patch more often. Their choices lined up with the ideal free distribution and the generalized matching law.

When the grain ratio was predictable, the rats' sensitivity shot up. They tracked small changes in food amount faster and more exactly.

Hursh et al. (1974) also ran rats in groups, but the task was lever pressing. Their groups paused less and pressed faster than singles. Lavinia et al. show the same pattern holds when animals move through space to feed.

Dugan et al. (1995) tested hens on two different responses (key peck vs. door push). They found constant bias; Lavinia et al. show predictability, not topography, is the new lever that sharpens choice.

Rilling et al. (1969) first proved time-allocation matching in pigeons. This study stretches that law to group foraging and adds the clear rule: stable schedules boost sensitivity.

If you run social skills groups or classroom centers, keep the reinforcement ratio steady while students learn the task. Once behavior is solid, you can thin or vary the ratio. Predictability first, flexibility later — the rats tell us sensitivity grows when the rule doesn't jump around.