Final answer:
Shallow processing requires little effort and leads to poor memory performance, whereas deep processing requires significant effort and leads to better memory performance.
Step-by-step explanation:
The difference between shallow and deep levels of processing is that shallow processing requires little effort and leads to poor memory performance, whereas deep processing requires significant effort and leads to better memory performance. Shallow processing involves encoding information in a superficial and surface-level manner, such as focusing on the physical features of a word or its sound. This type of processing does not promote strong memory retention. On the other hand, deep processing involves encoding information in a more meaningful and elaborative way, such as connecting it to personal experiences or linking it to existing knowledge. This level of processing enhances memory performance.