One literary device Alice Munro uses in her short story "The Bear Came over the Mountain" is nonlinear chronology. The story starts out with the heroin Fiona and her boyfriend Grant being college-aged, speaks of her parents, and recounts the moment Fiona proposed to Grant. The story then jumps forward in time to when Fiona is now 72, becoming senile, and Grant decides to place her in an expensive nursing home called Meadowlake. As the story continues, Munro continues to juxtapose the past with the present in order to reveal her central themes, which are reconciling with the aging process and failures in marriage.
Munro also uses a little bit of symbolism. Symbolism is when an author uses an object, character, place, or even a word to mean something beyond its literal meaning. One common example is a rose. On the surface, a rose is a flower, but it can also be used symbolically to express love, romance, or passion. We see one example of symbolism when Fiona proposes to Grant. Munro uses very descriptive imagery to point out that Fiona and Grant are on the beach at Port Stanley, on a "cold bright" and even windy day. We know it's windy because the author also describes sand "stinging their faces." What's more, "waves delivered crashing loads of gravel at their feet." This is not the typical calm, peaceful beach proposal on a balmy day under a picturesque sunset that one might normally picture. Munro very intentionally describes it as a harsh scene full of stinging sand, pebbles, and even both a cold and bright climate, yet it is also a pretty beach scene and a proposal scene. Her juxtaposition of the harsh elements at the beach with the brightness of the scene and the happy proposal is very similar to her juxtaposition of time throughout the short story. She is intentionally saying that the couple, though happy and with the prospects of a bright future, are also up for some harsh, stinging times, full of harsh crashing waves, and loads of pebbles. In other words, their marriage will prove to be rough, as seen later through Grant's elicit affairs. Hence, the stinging sand and waves full of pebbles symbolize the harsh realities of marriage they will soon face, which is, as said above, a central theme in the short story.
Beyond those, Munro doesn't really use many literary devices. However, one device she uses prolifically throughout the story is vivid imagery. Imagery is any word or phrase that conjures up a mental picture for the reader. The images will specifically relate to the four senses in order to paint a picture, those being touch, taste, sight, and sound (Dr. Wheeler, "Literary Terms and Definitions"). Aside from the beach scene above, the earliest examples of vivid imagery can be seen in the very first paragraph. One important example is the description of the house:
It was a big, bay-windowed house that seemed to Grant both luxurious and disorderly, with rugs crooked on the floors and cup rings bitten into the table varnish.
Here, the image of a "big, bay-windowed house" helps capture the size and style of the house, which was probably Victorian; the image of rugs, possibly Persian, helps capture the elegance of the house; and the image of "cup rings bitten into the table varnish" helps capture the "disorderly" damage that can be seen throughout the house. Just like the adjectives "luxurious and disorderly," from the start, Munro is setting up the house to juxtapose both happiness and discomfort, which again captures the main themes in the story. Though Fiona's life and her marriage to Grant have been happy, both her life and her marriage have also had their times of discomfort. Hence, even these images of the house in the very first paragraph help set up the story's themes.