BA410 Unit 8 Derived Stimulus Relations Paper Example

From a Light Above a Lever to Learning Who Belongs: A BA410 Unit 8 Discrimination and Derived Relations Paper

[Student Name]

Purdue University Global

BA410: Introduction to Experimental Analysis of Behavior

Unit 8 Discrimination and Derived Relations Paper

[Instructor Name]

[Date]

The writer, the lab, its animals and every figure are composite and illustrative; the studies cited are real.

Simple Discrimination in the Chamber

Discrimination training is the first phase of another study in the university lab where I work part time. One study in the lab begins with a phase of simple discrimination training. A small light above the lever turns on and off in random periods. Whenever the light is on, lever presses are reinforced with food on a variable interval schedule. When the light is off, presses produce nothing. At first, rats press at similar rates whether the light is on or off, because nothing in their history has given the light any meaning. After two weeks, a typical rat presses about twenty times more often when the light is on, and within a second or two of the light turning off, pressing nearly stops.

The light has become a discriminative stimulus, and lever pressing has come under its stimulus control. The mechanism is differential reinforcement: pressing in the light's presence is reinforced, pressing in its absence is extinguished, and over time the rat's behavior follows the light.

Conditional Discrimination

A more advanced study uses two levers and two cues, a tone and a flash of the house light. After the tone, presses on the left lever are reinforced; after the flash, presses on the right lever are. Neither lever is correct on its own. Which one is correct depends on another stimulus. This is a conditional discrimination, and it is the building block of more complex learning, including much of language.

Rats learn conditional discriminations more slowly than simple ones, often needing several weeks to reach high accuracy, but they do learn them. The graduate student running the study tracks the percentage of correct choices each session and moves a rat to the next phase only after several sessions above ninety percent. What they do not appear to do readily is what humans often do next.

Sidman's Discovery

Sidman (1971) worked with a young man with an intellectual disability who could match pictures to spoken words but could not read. Sidman taught him one new set of relations: when he heard a spoken word, he learned to choose the matching printed word. After this training, the young man could also match printed words to pictures and read the words aloud with comprehension, relations that had never been taught. Reading comprehension had emerged from the combination of what he already knew and what he had just learned. The result surprised even Sidman and launched decades of research.

Teaching one relation produced two more; the young man was reading words he had never been taught to read.

Stimulus Equivalence

Sidman and Tailby (1982) described the conditions for stimulus equivalence. After a learner is trained on conditional discriminations linking stimuli, such as A to B and B to C, equivalence is shown when three properties appear without training: reflexivity, matching each stimulus to itself; symmetry, reversing a trained relation, such as B to A; and transitivity, combining relations, such as A to C. When all three emerge, the stimuli form an equivalence class, and they become functionally interchangeable for the learner.

Equivalence helps explain how people learn so much more than they are directly taught. A child who learns that the spoken word dog goes with a picture and that the printed word dog goes with the same picture can relate the spoken and printed words without further instruction. Whether nonhuman animals show full equivalence remains debated, which is one reason the rats in my lab stop at conditional discriminations. Some studies with sea lions and other animals have reported results consistent with equivalence, but the evidence remains far stronger in humans.

Attitudes and Bias

Equivalence also has a darker side. If stimuli in an equivalence class share functions, then an emotional reaction attached to one member can transfer to the others. That process may help explain how people acquire attitudes toward groups they have never met. Mizael et al. (2016) worked with children who showed a bias favoring white faces over Black faces on a pretest. Through conditional discrimination training, they built equivalence classes that linked pictures of Black faces with abstract symbols that had previously been related to positive pictures. After training, many children showed reduced bias on the posttest, suggesting that the positive function had transferred to the Black faces through the equivalence class.

The study shows that the same processes that build reading comprehension can shape, and potentially change, attitudes. It also raises open questions about how much and how durably such training changes bias outside the laboratory, which the authors and others continue to study.

Ethical Questions

The bias study raises questions that the lab's light-and-lever research does not. Changing a child's attitudes, even toward less bias, is a powerful intervention, and it requires consent from parents, assent from children and careful thought about who decides which attitudes to target. Mizael and colleagues worked within an ethics review process, and their goal, reducing bias against Black people, is widely shared. But the same procedures could, in principle, be used to create or strengthen bias. Understanding how attitudes can be built through equivalence is therefore not only a scientific finding but a responsibility. It also suggests a caution for everyday life: children may acquire attitudes from patterns of pairing in the media and conversations around them, without any adult intending to teach them.

What Separates Humans and Rats

The rat in my lab can learn that a light signals food and that a tone tells it which lever to press. A child, learning relations among words, pictures and objects, derives a web of relations far larger than what was taught. Many researchers link this capacity to language, and later theories, such as relational frame theory, build on Sidman's work to explain how people relate stimuli in many ways beyond sameness.

Conclusion

Simple and conditional discriminations in the chamber show how stimuli come to control behavior through differential reinforcement. Sidman's discovery and Sidman and Tailby's account of stimulus equivalence show how humans go further, deriving relations that were never taught. Mizael and colleagues' work on racial bias shows that those derived relations can carry attitudes as well as meanings, and that understanding them may help change both.

References

Mizael, T. M., de Almeida, J. H., Silveira, C. C., & de Rose, J. C. (2016). Changing racial bias by transfer of functions in equivalence classes. The Psychological Record, 66(3), 451-462. https://doi.org/10.1007/s40732-016-0185-0

Sidman, M. (1971). Reading and auditory-visual equivalences. Journal of Speech and Hearing Research, 14(1), 5-13. https://doi.org/10.1044/jshr.1401.05

Sidman, M., & Tailby, W. (1982). Conditional discrimination vs. matching to sample: An expansion of the testing paradigm. Journal of the Experimental Analysis of Behavior, 37(1), 5-22. https://doi.org/10.1901/jeab.1982.37-5