Instinctive Drift

Instinctive drift is the tendency of animals to revert to their innate behaviors despite repeated reinforcement. Even when trained to perform a specific action for food, animals may abandon the learned behavior in favor of natural instincts. For example, a raccoon trained to deposit coins for food eventually rubbed the coins together instead, following its natural tendency to rub food. This demonstrates that biological predispositions limit which behaviors can be successfully trained through reinforcement.

Breland and Breland trained a raccoon to pick up two coins and place them in a container to receive food. Initially, the raccoon learned to associate the coins with food, making them a conditioned stimulus. Over time, however, the raccoon became less willing to deposit the coins and instead rubbed them together, following its innate behavior of rubbing food. This showed that instinctive drift can override learned behaviors even when reinforcement is consistent.

Instinctive drift reveals that innate biological factors restrict the range of behaviors that can be trained through reinforcement. Animals possess reflexes like the suckling reflex in infants and instincts like web-spinning in spiders that override learned associations. These biological predispositions limit which associations animals can form and which behaviors they will maintain, showing that conditioning alone cannot overcome fundamental biological drives.

When the raccoon's coins became a conditioned stimulus for food, the animal treated them as food rather than as tokens to exchange. The raccoon's natural instinct to rub food took precedence, causing it to rub the coins instead of depositing them. This illustrates that conditioned stimuli can trigger innate behaviors associated with the original stimulus, demonstrating how instinctive drift can disrupt learned behavioral chains.

Taste aversion learning demonstrates biological predispositions similar to instinctive drift. Rats failed to associate certain events like shocks or audiovisual stimuli with toxicosis, but readily associated specific flavors with illness. This shows that animals have innate biological constraints on which associations they can form, supporting the principle that instinctive drift and biological predispositions fundamentally limit what can be learned through conditioning.

Innate behaviors and biological predispositions play a significant role in determining the extent and nature of learning in animals. While reinforcement can influence behavior, these biological constraints restrict which behaviors can be trained and maintained. Understanding instinctive drift and biological factors is essential for predicting which learned behaviors will persist and which will be overridden by natural instincts.

Reinforcement cannot fully overcome an animal's natural instincts, as demonstrated by instinctive drift. Despite consistent food rewards, the raccoon eventually prioritized its innate rubbing behavior over the trained coin-deposit response. This shows that biological predispositions set limits on behavioral training, meaning that while reinforcement shapes behavior, it cannot eliminate fundamental instincts that conflict with learned associations.