Group foraging sensitivity to predictable and unpredictable changes in food distribution: past experience or present circumstances?
When reinforcement turns unpredictable, learners quickly drop old habits and follow the new payoff odds.
01Research in Context
What this study did
Researchers watched a small flock of pigeons peck at two patches. One patch always gave the same amount of grain. The other patch sometimes gave lots of grain and sometimes gave none.
The team switched the patches without warning. They counted where the birds went next. They wanted to know if the flock would keep following old rules or jump to the new odds.
What they found
When food turned random, the flock forgot yesterday’s hot spot. Within minutes most birds moved to the patch that now paid off.
The birds acted like the past never happened. Present odds beat past experience every time.
How this fits with other research
Miranda-Dukoski et al. (2014) saw the same quick switch, but only when a colored light told the pigeons the odds had changed. Without the light, the birds needed longer to catch on. E et al. left the light out and still got fast change, showing groups can track shifts without extra cues.
Szempruch et al. (1993) showed single pigeons also dump old wait-times when grain delays change. E et al. prove the rule works for whole flocks, not just lone birds.
Ono (2004) later found pigeons pick the option they have not seen lately. That lines up with E’s story: recent beats historical. Together they warn us that last week’s preference may already be stale.
Why it matters
Your client’s world can change like those grain patches. A new teacher, different room, or shifted token schedule can flip the value of old reinforcers. Run quick probes of current conditions instead of trusting last month’s data. If the reinforcer suddenly stops working, try fresh options right away. The past is a rough draft; today’s contingencies write the final version.
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02At a glance
03Original abstract
The ideal free distribution theory (Fretwell & Lucas, 1970) predicts that the ratio of foragers at two patches will equal the ratio of food resources obtained at the two patches. The theory assumes that foragers have "perfect knowledge" of patch profitability and that patch choice maximizes fitness. How foragers assess patch profitability has been debated extensively. One assessment strategy may be the use of past experience with a patch. Under stable environmental conditions, this strategy enhances fitness. However, in a highly unpredictable environment, past experience may provide inaccurate information about current conditions. Thus, in a nonstable environment, a strategy that allows rapid adjustment to present circumstances may be more beneficial. Evidence for this type of strategy has been found in individual choice. In the present experiments, a flock of pigeons foraged at two patches for food items and demonstrated results similar to those found in individual choice. Experiment 1 utilized predictable and unpredictable sequences of resource ratios presented across days or within a single session. Current foraging decisions depended on past experience, but that dependence diminished when the current foraging environment became more unpredictable. Experiment 2 repeated Experiment I with a different flock of pigeons under more controlled circumstances in an indoor coop and produced similar results.
Journal of the experimental analysis of behavior, 2002 · doi:10.1901/jeab.2002.78-179