Stimulus-food pairings produce stimulus-directed touch-screen responding in cynomolgus monkeys (macaca fascicularis) with or without a positive response contingency.
Stimulus-food pairings alone can make monkeys touch a screen, so watch for accidental autoshaping in your sessions.
01Research in Context
What this study did
The team worked with cynomolgus monkeys. They wanted to see if a picture on a screen could make the monkeys touch the screen, even when touching was not required to get food.
First, the monkeys saw a shape on the screen. Two seconds later, food dropped into the cup no matter what they did. This is called automaintenance or classical conditioning.
Next, the rule changed. Now the monkeys had to touch the shape to get the food. The researchers watched how fast the monkeys learned the new rule.
What they found
Every monkey started touching the screen as soon as the shape appeared. They did this even when touching was not needed.
When the rule switched to 'touch for food,' the monkeys kept touching. Their behavior changed right away when the contingency changed.
How this fits with other research
Brown et al. (1968) first showed this effect in pigeons. A light that always came before food made pigeons peck the key, even when pecking did nothing. The monkey study shows the same thing can happen with touch screens and primates.
Hartmann et al. (1979) found that tone-food pairings kept pigeons pecking, even when pecking turned the food off. The monkey data match this: stimulus-food links are powerful.
Kelly (1973) showed that food-paired signals can both slow down and speed up monkey responding, depending on the base rate. The new study adds that such signals can also create brand-new responses.
Why it matters
If you run non-contingent reinforcement phases, watch out. Clients may start new behaviors that seem 'operant' but are really driven by stimulus-reinforcer pairings. Check whether the behavior stays when you remove the contingency. If it does, you may need to extinguish the Pavlovian link before teaching the correct operant.
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02At a glance
03Original abstract
Acquisition and maintenance of touch-screen responding was examined in naïve cynomolgus monkeys (Macaca fascicularis) under automaintenance and classical conditioning arrangements. In the first condition of Experiment 1, we compared acquisition of screen touching to a randomly positioned stimulus (a gray square) that was either stationary or moving under automaintenance (i.e., banana pellet delivery followed an 8-s stimulus presentation or immediately upon a stimulus touch). For all subjects stimulus touching occurred within the first session and increased to at least 50% of trials by the end of four sessions (320 trials). In the subsequent condition, stimulus touching further increased under a similar procedure in which pellets were only delivered if a stimulus touch occurred (fixed ratio 1 with 8-s limited hold). In Experiment 2, 6 naive subjects were initially exposed to a classical conditioning procedure (8-s stimulus preceded pellet delivery). Despite the absence of a programmed response contingency, all subjects touched the stimulus within the first session and responded on about 50% or more of trials by the second session. Responding was also sensitive to negative, neutral, and positive response contingencies introduced in subsequent conditions. Similar to other species, monkeys engaged in stimulus-directed behavior when stimulus presentations were paired with food delivery. However, stimulus-directed behavior quickly conformed to response contingencies upon subsequent introduction. Video recordings of sessions showed topographies of stimulus-directed behavior that resembled food acquisition and consumption.
Journal of the experimental analysis of behavior, 2009 · doi:10.1901/jeab.2009.92-41