Effects of ratio contingencies on responding maintained by schedules of electric-shock presentation (response-produced shock).

Researchers compared how pigeons peck when electric shocks follow every few pecks. They tested fixed-ratio (FR) and variable-ratio (VR) schedules against a fixed-interval (FI) schedule. All birds first learned to peck for shock; then each schedule ran for several sessions while response rates were counted.

Pecking dropped when shocks came on ratio schedules. Both FR and VR produced fewer total responses than the FI schedule. The birds simply stopped working as hard when each shock was tied to a set number of responses.

McKearney (1970) had already shown that FR and FI schedules make their usual ‘burst’ and ‘scallop’ patterns even with shock. N et al. now add that those FR bursts do not last—overall responding weakens.

AZRIN et al. (1963) saw the same weakness under FR punishment: less suppression than continuous shock. Together the papers warn that intermittent ratio shocks quickly lose their power, whether the shock is meant to punish or maintain behavior.

Wallander et al. (1983) later zoomed in on the pigeons’ timing and found short pauses after each shock under ratio rules. That micro-analysis helps explain why ratio schedules fail to keep shock-maintained responding alive.

If you ever use aversive contingencies in translational or animal work, choose interval schedules over ratio ones. Interval rules keep responding steadier and avoid the rapid drop seen here. The finding also reminds us that schedule structure, not just the consequence’s valence, controls behavior.