why do people tend to ignore the importance of Multicultural Psychology ?

That's a pretty broad statement. What evidence do you have that "people" ignore the importance of multicultural psychology?

Those who do ignore this probably do so out of ignorance or perhaps distrust of people who are different. Check this site.

http://findarticles.com/p/articles/mi_m0825/is_4_71/ai_n15970797/

Much of this is linked to prejudice, especially the factor of ethnocentrism.

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People may tend to ignore the importance of Multicultural Psychology for a variety of reasons. Some possible explanations include:

1. Lack of awareness: Many people may not be aware of the field of Multicultural Psychology and its significance. They may not understand the value of studying the impact of culture on psychology.
2. Limited exposure and understanding: Some individuals may have limited exposure to and understanding of different cultures. As a result, they may fail to recognize the impact of culture on psychological processes and believe that all individuals share similar experiences.
3. Stereotyping and biases: Preconceived stereotypes and biases can lead people to overlook the importance of multicultural psychology. Stereotypes can simplify complex cultural experiences and overlook the diversity within groups.
4. Dominance of mainstream perspectives: Many psychological theories and practices are based on studies conducted with predominantly Western samples. This can lead to a lack of acknowledgment and understanding of non-western perspectives and cultural variations.
5. Resistance to change: The recognition of multiculturalism challenges the traditional and often ethnocentric perspectives. People who are resistant to change may find it difficult to accept and embrace the importance of multicultural psychology.

To address this issue and promote the importance of Multicultural Psychology, it is crucial to raise awareness and educate individuals about the impact of culture on psychological processes. Encouraging diverse perspectives, challenging stereotypes, and highlighting the benefits of multiculturalism can also be helpful in fostering a greater understanding and appreciation for Multicultural Psychology.