Written by Richard H. Thaler & Cass R. Sunstein, who are economists (Cass Sunstein heads the White House Office of Information and Regulatory Affairs), Nudge is about how decisions about public policy, healthcare, the environment, and saving for retirement can be improved.

[From the Great Books Series. Also see The Success Manual  - Encyclopedia of Advice, which contains summaries of 100+ Most useful books.]

Some insights:

What is a nudge?
A nudge is any aspect of the design of a choice (“choice architecture”) that alters people’s behavior in a predictable way, without forbidding anything or actually changing the choice at all.

The example that went out in the event invitation was the clever internet cafe named their wireless network “Have you tried the carrot cake.”

Why do we need nudges?
Freedom of choice is best, right? Many economists (and some of the engineers I know) like to say that we don’t know better than the user/chooser, that we should present all options to people, and let them choose. This makes the false assumption that almost all people, almost all of the time, make choices that are in their best interest, or at least are better than choices someone else would make for them.

There is no such thing as a nudge-less choice.
SOMETHING is always influencing your choices. People are influenced by small factors in the design of an experience, so even if you don’t consciously design your choice architecture, it is still there, affecting the actions of the choosers.

When do we especially need nudges?
This happens predictably in the following scenarios:
- When we see the benefits now, costs later.
- When encountering decisions we make infrequently: We get better at everything through practice.
- When feedback is not immediate.
- When it is hard to imagine the possible outcomes.

3 of the main ways to predict what people will do.
1. We have predictable mental biases.
Anchoring Bias: We are heavily biased by where we start.
Availability Bias: We overestimate the likelihood of events we can easily remember. ?
Representativeness Bias: We someetimes see patterns where there are none.
Unrealistic Optimism: Almost all of us think we are better than average.
Loss Aversion: We are happy when we gain something, but twice as unhappy when we lose it.
Status Quo Bias: We rarely overcome inertia.
Framing Bias: “10 out of 100 die.” vs. “90 out of 100 are cured.”
Priming Bias: What we see or hear immediately before a choice affects how we behave.

2. We predictably succumb to temptation.
The Spock-Homer empathy gap: Your planner does not fully appreciate how much your behaviors are altered when you are under the influence of temptation. Your planner does not fully appreciate how much your behaviors are altered when you are under the influence of temptation.
You also have a third system... Mindless choosing: your autopilot just continues doing what it’s used to - driving the same route, or continuing to eat when there’s food in front of you.

3. We predictably follow the herd.
We like to conform. This is at the root of speculative bubbles, internet memes, and fads. One phenomenon that drives us to conform is the “spotlight effect,” which makes us feel like people are paying closer attention to us--especially when we’re not conforming--than they really are. (I have a feeling this dude with the emover thinks everyone is paying attention to him.
One particularly interesting ramification of the herd behavior is its effect on popularity lists. One experiment offered different groups of people the same set of downloadable mp3s with visible popularity data. In the end, the most popular songs for each group were not predictable and were not similar from group to group, except that they were lucky and picked by the first users of the system.

So how can we help our Spock defeat our Homer?
Incentives: e.g. a social program that gives teen moms a dollar a day every day that they are not pregnant.
Understand “mappings”: How we translate data about an option into what it actually means for us, like translating kilowatts of energy into dollars on the electricity bill, or translating megapixels to maximum print size.
Defaults: Not new to us - defaults are POWERFUL because of the Status Quo bias. You can default to opt-in, opt-out, or mandatory choice (which is like having yes/no radio buttons with nothing selected).
Give Feedback
Expect Error
Structure Complex Choices: The paradox of choice is reduced if options are grouped. Or use strategies like “collaborative filtering” to reduce options presented.

To summarize: Nudges are about designing choices to try to help people make choices more with their rational mind (their inner Spock) and less with their gut. There are certain situations: Benefits now, cost later; decisions we have to make infrequently, places where the feedback isn’t immediate or the outcome is hard to imagine, where the Homer in us has the upper hand, and we can use our knowledge of our predictable psychology in these ways mentioned: incentives, understanding mappings, defaults, giving feedback, and structuring complex choices to nudge our Spock to rebalance the power.