Reader’s Question

Recently I got into a debate with my AP Psychology teacher about some psychology topics, and I would like to get some resolve. Given that my teacher lacks a degree in even undergraduate psychology, I thought my arguments might be strengthened by input from a psychologist. These are the three questions I would like to address:

When testing how hereditary a certain trait is, would it be better to raise identical twins apart or to raise fraternal twins together? Would it make any difference whatsoever which method is used? My contention is that both are valid; my teacher’s contention is that only the latter is valid. I believe that by eliminating one of the two variables by controlling them (i.e., environment/genetics), we can easily deduce which trait belongs to which category (environmental/genetic) and that it does not matter which variable we eliminate.

Does delayed reinforcement or intermittent reinforcement retain a behavior longer in an individual? I believe both retain a behavior for long periods of time, as delayed reinforcement is somewhat like partial/intermittent reinforcement in that not all actions are reinforced immediately, if at all. My teacher contends the latter reinforces longer.

Final question: I contend that negative reinforcement is the EXACT SAME THING as punishment. Punishment and negative reinforcement both use negative stimuli to remove undesirable behavior and to enforce the opposite behavior, right? Punishment is the removal of a behavior (which implies the reinforcement of its opposite behavior), whereas negative stimulus is the reinforcement of an opposite behavior (which implies the removal of a certain behavior).

Our Clinical Psychologist’s Reply

It’s quite apparent why you’re in such a debate. The facts of the matter are that none of the issues you’re debating are as clear-cut and easily resolved as you might wish (with the possible exception of the issue on negative reinforcement).

Because the issue of whether negative reinforcement is the exact same thing as punishment is more easily resolved, let’s take it first. Negative reinforcement is increasing the likelihood a behavior will occur again by removing an aversive consequence to it. So, it’s encouraging a behavior by taking something negative away as opposed to associating a desirable consequence with the behavior (i.e., positive reinforcement).

Punishment is decreasing the likelihood of a behavior by introducing an aversive consequence (i.e., positive or Type I punishment) or by removing a desirable situation (i.e., negative or Type II punishment). Negative reinforcement is often confused with punishment but the two are definitely different. And you have some points to make about the similar issues involved. But in science, it’s extremely important to define the terms we use to describe various phenomena. Without operational definitions, we can’t communicate or interpret our scientific findings accurately and reliably.

Your other two questions are not as easily settled. Intermittent schedules of reinforcement make behaviors less resistant to extinction. But as far as retaining behaviors or prompting high rates of responding, variable (as opposed to “fixed”) schedules of reinforcement are best.

Resolving the heredity vs. environment question has been a longstanding controversy in the field. The fact is that neither studies of identical twins reared apart nor fraternal twins reared together generally yield definitive answers on the question, although because of the variability involved, interpretation of the results of studies that examine fraternal twins reared together are much more subject to debate. Although there are rarely situations in which a trait is so heavily genetically influenced that it always shows up in identical twins no matter where or how they are raised, high concordance rates on a particular variable for identical twins reared apart provide some very strong support that a genetic factor is at work (although the factor might require a particular environment to exist for it to be expressed).

Enjoy your scientific debates! But remember, science is advanced not only by honest skepticism but also by drawing careful and reliable distinctions in the terms we use as well as the methods we employ.