2. What Is Deductive Reasoning?
• Deductive reasoning is the process of reasoning from one or more
general statements regarding what is known to reach a logically
certain conclusion.
• One of the primary types of deductive reasoning is conditional
reasoning, in which the reasoners must draw a conclusion based on
an if-then proposition.
3. What Is Inductive Reasoning?
• Inductive reasoning is the process of reasoning from specific facts or
observations toreach a likely conclusion that may explain the facts.
The inductive reasoners thenmay use that probable conclusion to
attempt to predict future specific instances
• The key feature distinguishing inductive from deductive reasoning is
that, in inductive reasoning, we never can reach a logically certain
conclusion. We only can reach a particularly well-founded or probable
conclusion.
4. Causal Inferences
• One approach to studying inductive reasoning is to examine causal inferences—how
people make judgments about whether something causes something else
• First one thing happens, then another. If we see the two events paired enough, we may
come to believe that the first causes the second.
• We demonstrate confirmation bias, which may lead us to errors
• Correlational evidence cannot indicate the direction
• of causation. Suppose we observe a correlation between Factor A and Factor B. We
may find one of three things:
1. it may be that Factor A causes Factor B;
2. it may be that Factor B causes Factor A; or
3. some higher order, Factor C, may be causing both Factors A and B to occur together.
5. Reasoning by Analogy
• Inductive reasoning may be applied to a broader range of situations than those
requiring causal or categorical inferences. For example, inductive reasoning may
be applied to reasoning by analogy. Consider an example analogy problem:
Fire is to asbestos as water is to: (a) vinyl, (b) air, (c) cotton, (d) faucet.
In reasoning by analogy, the reasoner must observe the first pair of items (“fire”
and “asbestos” in this example) and must induce from those two items one or more
relations (in this case, surface resistance because surfaces coated with asbestos can
resist fire). The reasoner then must apply the given relation in the second part of
• the analogy. In the example analogy, the reasoner chooses the solution to be
“vinyl” because surfaces coated with vinyl can resist water
6. • The difficulty of encoding can become even greater in various
puzzling analogies. For example, in the analogy:
RAT : TAR :: BAT : (a. CONCRETE, b. MAMMAL, c. TAB, d. TAIL)
7. Neuroscience of Reasoning
• As in both problem solving and decision making, the process of
reasoning involves the prefrontal cortex (Bunge et al., 2004). Further,
reasoning involves brain areas associated with working memory, such
as the basal ganglia (Melrose, Poulin, & Stern, 2007). One would
expect working memory to be involved because reasoning involves
the integration of information (which needs to be held in working
memory while it is being integrated).
• The basal ganglia are involved in a variety of functions, including
cognition and learning. This area is also associated with the prefrontal
cortex through a variety of connections (Melrose, Poulin, & Stern,
2007).
