We sometimes think that everything was much better and easier in the past. It's one of the tricks our minds play on us, especially when we are in low spirits.

Actually, it's unlikely that things were objectively better in the past. This form of thinking is calledrosy retrospection, which is a well-studied cognitive bias. It happens because when we think about the past, we are more likely to focus on positive generalities than annoying details.

If you think back to a holiday with your family five years ago, you're likely to recall the beautiful views rather than the uncomfortable bed. In other words, the negative details disappear from our memory over time while the positive ones remain.

Rosy retrospection can influence how we make decisions, and it's one of the reasons why we easily return into problematic relationships. The longer it is since we experienced the negative influence of a relationship, the more likely we are to let the good memories outweigh the bad memories and to perhaps forgive unforgivable behavior. It's always a good idea to review our nostalgic (怀旧的) feelings with a healthy degree of doubt.

But rosy retrospection does serve an important purpose. It keeps us in a positive state of mind in the present and is important to our psychological wellbeing. In fact, people who tend to remember negative experiences more than positive ones are likely to exhibit psychological disorders. Research generally suggests that our happiest days are still to come. And even if they're not, it's still important to believe that they are. Don't shy away from looking upon the past with a certain degree of nostalgia. But, for the same reason, don't use the past as an excuse to be unhappy in the present.

If you remember anything before the age of 3, your brain only puts together bits of reality that you've learned as you've grown up, according to a new research. In the largest study of its kind, researchers asked people about their earliest memory and at what age they believe it took place. They found that a surprising number of people claimed to remember things from their first years of life. But scientists agree that our brain isn't developed enough to keep memories until we're three years old, so researchers wanted to know why so many people insist they remember something before then.

Of 6, 641 participants, 37. 4 percent said they had their first memory before the age of 2. Of those, 893 said their first memories were from the period before they turned 1. Participants' answers were analyzed in terms of their age, language, the content of the memory and the nature of the memory.

" When we looked through the answers from participants, we found that a lot of these first ‘memories' were frequently related to infancy and a typical example would be a memory based around a baby carriage, " said Professor Martin Conway at City University of London.

This means that many of these " fictional" memories are only our minds mixing up what we know about babies and what we actually experienced as a baby. They also found that older people were more likely to report remembering a " fictional" early memory. Researchers couldn't determine why our brains do this but suggested it comes from a personal need to have a complete description of our lives. They added that a positive self-narrative can lead to a better life.

What kind of people can become scientists? When a group of researchers posed that question to ninth-and 10th-graders, almost every student gave such responses as "People who work hard" or "Anyone who seems interested in the field of science."

Many of these same students struggled to imagine themselves as scientists, citing concerns such as "I'm not good at science" and "Even if I work hard, I will not do well." It's easy for them to see a scientist's work as arising from an inborn talent.

But for high school students, learning more about some struggles of scientists can help students feel more motivated to learn science. Researchers at Teachers College, Columbia University and the University of Washington designed an intervention to change students' beliefs that scientific achievement depends on ability rather than effort by exposing students to stories of how accomplished scientists struggled and overcame challenges in their scientific efforts.

During the study, the students read one of three types of stories about Albert Einstein, Marie Curie and Michael Faraday. Intellectual(智力的)struggle stories: stories about how scientists "struggled intellectually," such as making mistakes while addressing a scientific problem and learning from them. Life struggle stories: stories about how scientists struggled in their personal lives, such as not giving up in the face of poverty or lack of family support. Achievement stories: stories about how scientists made great discoveries, without any discussion of coexisting challenges.

Researchers found that students who heard either type of "struggle stories" improved their science performance after-intervention, compared to students in the control group. The effect was especially pronounced for lower performing students, for whom exposure to struggling stories led to significantly better science-class performance than low-performing students who read achievement stories. In addition, students who read struggle stories reported feeling more personally connected to the scientists. By recognizing a scientist's struggles and introducing the growth mindset he or she applied to accomplish great works, the students were able to empathize(共情)with the scientists during their own struggles.