Final answer:
The working memory model proposed by Baddeley and Hitch provides evidence that short-term memory is not a unitary store by suggesting distinct components for processing different types of information, overseen by a central executive.
Step-by-step explanation:
An example of evidence that shows that the short-term memory is not a unitary store is the working memory model proposed by Baddeley and Hitch in 1974. This model suggests that there are multiple components to short-term memory, each with its own function, such as the visuospatial sketchpad, the episodic buffer, and the phonological loop, with a central executive coordinating these components. This evidence counters the once-prevailing Atkinson-Shiffrin model that depicted short-term memory as a single, linear process.
The working memory model expands upon the idea of short-term memory by incorporating the concept that different types of information are processed and stored in separate systems. The phonological loop handles verbal and auditory information, the visuospatial sketchpad deals with visual and spatial information, and the episodic buffer integrates information across these domains under the supervision of the central executive, which also plays a key role in the process of encoding information from short-term to long-term memory.