Functional fixedness is a tendency to only think of an object's most common use when presented with a problem. For instance, if you are trying to open up an old-fashioned Coke and need a bottle-opener you may be so focused on finding a bottle-opener as opposed to using your keys. Your keys would work just as well, but because you are so focused on using it to open the door you don't think of its alternative use. 

Researchers have identified several mental obstacles to our problem solving/reasoning processes. Functional fixedness, mental set, and making assumptions, and irrelevant information are just some of many. Although their precise definitions won't be defined here, the commonality they share is a misdirection in focus and to an extent being stuck on what has worked in the past.

A "mental set" is an obstacle to problem solving which involves fixating only on solutions that have worked in the past. For instance, someone who knows that yelling and throwing a fit has gotten them what they wanted might only use this solution to get they want in the present. Instead, it might be more effective to think of a new solution.

Decision-making involves weighing alternatives and choosing between them. The other answers are a part of decision making but are too specific to the methods for our decision making processes. For instance, it isn't just risky decisions that involve weighing alternatives and choosing between them, but all decisions. The other answers are strategies for how we weigh the alternatives at hand. 

Additive strategies are commonly used when people are making decisions about their preferences. When using an additive strategy, a person lists the traits of each potential choice, weights them according to importance, adds them up, and determines which one is more appealing based on the result. Another common strategy is a strategy of elimination, which will not be discussed in detail here.

This is an elimination strategy. An elimination strategy is a decision making strategy where one sets a certain criteria and any options that do not meet this criteria will be automatically be eliminated. Although John deciding where to eat is certainly a form of judgment and cognition, these answers aren't sufficient because they are not as specific to what this process was. An additive strategy is a different type of process all together.

Functional fixedness is a cognitive bias that limits the way a person thinks about an object, restricting his or her view of that object’s uses to the “traditional” or typical uses of that object. The example with Joanne is the best choice, as it reflects functional fixedness restricting her view of the staple remover. She is probably used to using the staple remover to remove staples, so when she realized she could not open the keychain ring with her nails, she felt stuck. She did not think of being able to use the staple remover to hold open the keychain ring. 

Sigmund Freud is considered to be "the father" of psychoanalysis. This theoretical orientation believes that people can be cured of psychiatric illnesses by bringing their unconscious thoughts to the surface to be addressed. This allows repressed emotions and behaviors to be released and dealt with by the therapist and patient. 

A succinct and clear definition for cognition could be the following: "thinking, reasoning, remembering or almost any other activity in the brain." Cognition drastically changes throughout our lifetimes and is the object of much psychological study. In other words, the correct choice for the basic and clear definition of cognition is the following: "cognition relates to almost any activity in the brain, particularly thinking, reasoning and remembering."

The confirmation bias is a fallacy almost all of us are prone to. The premise of the confirmation bias is that we seek out things in the world the confirm our preformed thoughts about the world. That is, in terms of what we think, believe, do and are interested in we tend to be very narrow! That's why throughout a lifetime people will not change political beliefs and are often found browsing the same political website they have for years.