The Brain of a Spider/Loading a Program

Long ago I noticed a large spider web and idly dropped a piece of grass in it. Spiders of course are very interested in such an event -- it might mean a meal. The spider immediately began a cautious approach to the debris and eventually carefully extricated it. It somehow determined that this was not prey and wanting its web to remain almost invisible, the object needed to be removed. The interesting thing I observed is that when I repeated the experiment several seconds later the spider immediately removed the stuff. Apparently, the spider was remembering what had happened earlier and reacting accordingly.

(Inevitably anthropomorphizing as humans tend to do, it seemed annoyed the second time.)

But I wrote to a scientist who studies spider cognition and he suggested that instead of the spider "thinking" or drawing a conclusion or even remembering what has just occurred, what was actually happening is that a sort of behavioral program had been "loaded into memory" and this accounted for the much faster reaction to the piece of grass.

I do not think he knew I was a s/w developer, but naturally I found this idea fascinating and later wondered, just what is happening in the spider's brain when such a program is loaded? Could this be seen somehow?

I also wonder what would have happened if a fly had within a short time gotten caught in the web -- would this "program" have caused the spider to treat the prey as debris? Or would it have proceeded normally and immobilized the fly?

It is hard for me to completely accept that no reasoning was involved -- if indeed there is some sort of awareness or reasoning, spiders certainly manage to get a lot of bang for the buck from such small brains (although according to the article referenced, bigger and more complex than once thought). It is certainly true that many species have in recent years, including insects, shown genuine learning ability. But again, this program idea is fascinating to me: where would such programs be stored in the spider brain prior to being "loaded"? What is this "loading" process?