2 questions
1. The one way to get over this causes is to practice reaching out – who knows, commuting could become more enjoyable.
What is "reaching out"?
2. Then, researchers had the volunteers fill out a lengthy narcissism clinical assessment. Those who had rated themselves high on the narcissism scale also scored high on the assessment.
What's the difference between "lengthy" and "long"?The sentence is marked:◆◆◆
Context:
20140912-Talking to Strangers Makes You Happy
Consider the times you’ve hopped on a subway, boarded a plane or entered a waiting room. Chances are, you probably avoided engaging with any fellow commuters or patients. But contrary to what we might think, we’d be happier if we did strike up a conversation with a total stranger.
In a study, commuters in Chicago were asked to either talk with a stranger on a train, or sit quietly alone, or do whatever they’d normally do on their commute. Then, they responded to a survey about how they felt.
Turns out those who engaged with strangers had the most pleasurable experience and those who remained solitary on the train had the least enjoyable experience. These answers were compared with another group that did not participate but instead had to predict how they might feel in each situation. This group thought talking with strangers would be the least enjoyable, by far. The study is the journal of Experimental Psychology. [Nicholas Epley & Juliana Schroeder: Mistakenly Seeking Solitude]
So despite being social animals and enjoying social engagement, we avoid chatting with strangers. Why? Well, according to a follow up study it’s because we think, wrongly, that strangers don’t want to talk with us. ◆◆◆The one way to get over this causes is to practice reaching out – who knows, commuting could become more enjoyable.◆◆◆
—Christie Nicholson

Question

2 questions
1. The one way to get over this causes is to practice reaching out – who knows, commuting could become more enjoyable.
What is "reaching out"?
2. Then, researchers had the volunteers fill out a lengthy narcissism clinical assessment. Those who had rated themselves high on the narcissism scale also scored high on the assessment.
What's the difference between "lengthy" and "long"?The sentence is marked:◆◆◆
Context:
20140912-Talking to Strangers Makes You Happy
Consider the times you’ve hopped on a subway, boarded a plane or entered a waiting room. Chances are, you probably avoided engaging with any fellow commuters or patients. But contrary to what we might think, we’d be happier if we did strike up a conversation with a total stranger.
In a study, commuters in Chicago were asked to either talk with a stranger on a train, or sit quietly alone, or do whatever they’d normally do on their commute. Then, they responded to a survey about how they felt.
Turns out those who engaged with strangers had the most pleasurable experience and those who remained solitary on the train had the least enjoyable experience. These answers were compared with another group that did not participate but instead had to predict how they might feel in each situation. This group thought talking with strangers would be the least enjoyable, by far. The study is the journal of Experimental Psychology. [Nicholas Epley & Juliana Schroeder: Mistakenly Seeking Solitude]
So despite being social animals and enjoying social engagement, we avoid chatting with strangers. Why? Well, according to a follow up study it’s because we think, wrongly, that strangers don’t want to talk with us. ◆◆◆The one way to get over this causes is to practice reaching out – who knows, commuting could become more enjoyable.◆◆◆
—Christie Nicholson

Answer

"Reaching out" in this case is the act of making the active effort to start a conversation with someone (a stranger/commuter/etc.). In your sentence, it suggests that reaching out may make commuting more enjoyable; starting a conversation with another commuter could make commuting more fun.

Lengthy and long are somewhat interchangeable. Lengthy simply mean that something has considerable length. For example you can both say "That is a long road" and "That is a lengthy road". However, for some things it would sound weird to use lengthy instead of long; an example being "She has long hair" and "She has lengthy hair". You would say the first more commonly than the second. If in doubt, use "long".

Answer

Reaching out = starting conversations with other people.

In other contexts you can also reach out for help which means to ask someone for help.

Both lengthy and long mean long, lengthy tends to also mean tediously long. "A lengthy walk" can be used to describe a long walk which makes you really tired and not feel like completing it.