ABA Fundamentals

Choice for signalled over unsignalled shock as a function of shock intensity.

Harsh et al. (1975) · Journal of the experimental analysis of behavior 1975
★ The Verdict

When aversives intensify, animals want a warning — a rule you can use to soften transitions in clinical work.

✓ Read this if BCBAs who use DRA, extinction, or correction procedures with kids or adults who show escape or avoidance.
✗ Skip if Practitioners working solely with reinforcement-only programs where aversive stimuli never appear.

01Research in Context

01

What this study did

Aragona et al. (1975) let rats pick between two levers. One lever gave a mild foot-shock right away. The other gave the same shock, but a light flashed first to warn them.

The team then turned the shock up in small steps. They watched how the animals' choices changed as the pain grew stronger.

02

What they found

At low shock levels the rats did not care which lever they pressed. As the shock got stronger, every animal moved to the lever with the warning light.

By the highest level all rats chose the signaled shock almost every time. The worse the pain, the more they wanted a heads-up.

03

How this fits with other research

Blanchard et al. (1979) ran the same setup but changed how long the warning light stayed on. They found the rats only picked the signaled side once the light lasted two seconds or more. This direct replication shows both intensity and signal length control choice.

Nevin et al. (2016) took the idea into a preschool. Kids with developmental disabilities got reinforcement for good behavior. When the reinforcer was signaled, problem behavior stayed low and relapse was smaller. The lab rule 'warnings help' now works in clinical DRA plans.

KAPLAN et al. (1965) saw a twist: rats escaping bright light ran fastest at medium intensity, not the brightest level. Their curve was an upside-down U, while J et al. found a straight rise. The difference is the task — choice versus escape — so the two studies actually map different parts of coping.

04

Why it matters

You can build warning stimuli into behavior plans. A two-second visual cue before a demand or correction can cut problem behavior and later relapse. Start with clear, brief signals and watch the learner's preference; if the task gets harder, the value of that cue will grow.

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→ Action — try this Monday

Add a two-second visual cue before each difficult demand; track if problem behavior drops across the week.

02At a glance

Intervention
not applicable
Design
single case other
Sample size
7
Finding
positive

03Original abstract

Choice between a signalled shock schedule and an unsignalled one was examined at various shock intensities. Three rats were given the opportunity to change from the unsignalled schedule to the signalled one at intensity values between 0.15 mA and 1.0 mA. Steps were usually 0.15 mA and both ascending and descending series were given. For two other rats, shock intensity increased from 0.20 mA to 1.0 mA in 0.20-mA increments; for two additional rats, shock intensity was first 3.0 mA and was then reduced to 1.0 mA. Subjects tended to remain in the unsignalled schedule at the lower shock intensities, but spent most of each session under the signalled schedule at the higher intensities (1.0 mA and 3.0 mA). In addition, the time spent in the signalled schedule tended to vary systematically with shock intensity over at least part of the range of intensity values. It was concluded that the relationship between shock intensity and choice behavior is similar to the relationship between intensity and behavior in procedures involving avoidance, escape, and punishment.

Journal of the experimental analysis of behavior, 1975 · doi:10.1901/jeab.1975.23-349