Unconditioned Stimulus

Synonyms

Unconditional Stimulus

Definition

A stimulus that automatically elicits a response without prior learning (Chance 2009).

Introduction

The unconditioned stimulus (UCS) is a term described in the learning literature to describe a stimulus that automatically elicits a response (Chance 2009). The UCS is innate; no prior learning has to occur in order for the UCS to elicit a response. Unconditioned stimuli have “survival value” or are pertinent for survival (Domjan 2015) and examples can include smell, food, water, pain, temperature, and sexual stimulation. Conversely, the conditioned stimulus (CS) is a stimulus that elicits a response after it is associated with the UCS. Unlike the UCS, the CS requires prior learning in order to elicit a response, which becomes the conditioned response (CR; Krause and Corts 2014).

Standard Paradigm of the Unconditioned Stimulus

Ivan Pavlov, a famous nineteenth century physiologist, first described classical conditioning and the UCS when he began...