Conditioned suppression as a sensitive baseline for social facilitation.
A co-actor turns strong conditioned suppression into even stronger suppression, giving researchers a louder fear signal.
01Research in Context
What this study did
Hake et al. (1969) worked with pigeons that were already afraid of a warning tone. The tone meant a shock might come.
The birds pecked a key for food. When the tone played, they usually froze. The team added a second pigeon next to the first. They wanted to see if the buddy would change the freezing.
What they found
When the lone bird was already freezing hard (more than 40% drop in pecks), adding a co-actor made the freezing even stronger. The extra suppression only showed up when the baseline fear was high.
If the bird was only a little scared, the buddy had no effect. The social boost needed a strong fear base to latch onto.
How this fits with other research
Rees et al. (1967) showed that a tone paired with nalorphine also shuts down lever pressing in monkeys. F et al. used the same fear-tone trick, but added a friend to magnify it.
Azrin et al. (1969) found that a cue for free food can also suppress responses. Their reinforcer was nice, not scary. Together, these studies show that both good and bad upcoming events can freeze behavior, yet only the scary ones get stronger with a peer nearby.
Blue et al. (1971) proved the freeze is not because the response was punished. F et al. build on that by showing the freeze can still be socially pumped up.
Why it matters
If you run conditioned-suppression probes to test fear, add a peer to make tiny differences huge. This is handy when evaluating anti-anxiety meds or social skills treatments. A high-suppression baseline plus a co-actor gives you a clearer signal with fewer animals or sessions.
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02At a glance
03Original abstract
The key pecking of pigeons maintained on a variable-interval schedule of food reinforcement was suppressed during occasional presentations of a warning stimulus paired with electric shock. On alternate sessions, a co-actor pigeon was visible in an adjoining chamber where it emitted the same food-reinforced key peck during the warning stimulus that signalled shock for the subject. With no shock and at low shock intensities, where the subject's responding was not suppressed or suppressed only slightly, the co-actor had little effect. At the higher shock intensities, where the subject's responding was reduced by at least 40%, the response rate during the warning stimulus was consistently higher when the co-actor was present. One explanation of these results assumes a special relationship between social stimuli and aversive stimuli in which the presence of another animal reduces emotional reactions and thereby allows operant responses to increase. This was not the case here because the mere presence of the co-actor did not maintain social facilitation. Rather, the present results, taken in conjunction with previous findings, suggest that changes in social and non-social variables which affect the rate of food-reinforced responding may produce proportionately larger changes in responding when that responding is suppressed by aversive stimulation than when it is not.
Journal of the experimental analysis of behavior, 1969 · doi:10.1901/jeab.1969.12-807