Editing Interpersonal attraction (section)

===Similarity attraction effect===
The proverb "birds of a feather flock together" has been used to illustrate that similarity is a crucial determinant of interpersonal attraction.<ref>{{cite journal | last1=Heine | first1=Steven J | last2=Foster | first2=Julie-Ann B. | last3=Spina | first3=Roy | title=Do birds of a feather universally flock together? Cultural variation in the similarity-attraction effect | journal=Asian Journal of Social Psychology | year=2009 | volume=12 | issue=4 | pages=247–258 | doi=10.1111/j.1467-839X.2009.01289.x| doi-access=free }}</ref> Studies about attraction indicate that people are strongly attracted to lookalikes in physical and social appearance. This similarity is in the broadest sense: similarity in bone-structure, characteristics, life goals and physical appearance. The more these points match, the happier, satisfied and prosperous people are in these relationships.<ref>{{cite journal | last1 = Folkes | first1 = V. S. | year = 1982 | title = Forming relationships and the matching hypothesis | journal = Personality and Social Psychology Bulletin | volume = 8 | issue = 4 | pages = 631–636 | doi=10.1177/0146167282084005| s2cid = 143529355 }}</ref>

The lookalike effect plays the role of self-affirmation. A person typically enjoys receiving confirmation of aspects of his or her life, ideas, attitudes and personal characteristics, and people seem to look for an image of themselves to spend their life with. A basic principle of interpersonal attraction is the rule of similarity: similarity is attractive — an underlying principle that applies to both friendships and romantic relationships. The proportion of attitudes shared correlates well with the degree of interpersonal attraction. Cheerful people like to be around other cheerful people and negative people would rather be around other negative people.<ref>{{cite journal | last1=Locke | first1=Kenneth D. | last2=Horowitz | first2=Leonard M. | title=Satisfaction in interpersonal interactions as a function of similarity in level of dysphoria. | journal=Journal of Personality and Social Psychology | date=1990 | url=https://pdfs.semanticscholar.org/be04/40b01a3c540c8e374ace7cb340f053166576.pdf | archive-url=https://web.archive.org/web/20180119120232/https://pdfs.semanticscholar.org/be04/40b01a3c540c8e374ace7cb340f053166576.pdf | url-status=dead | archive-date=2018-01-19 | doi=10.1037/0022-3514.58.5.823 | issn=1939-1315 | volume=58 | issue=5 | pages=823–831| pmid=2348370 | s2cid=3167124 }}</ref> A 2004 study, based on indirect evidence, concluded that humans choose mates based partly on facial resemblance to themselves.<ref>{{cite journal | title=Narcissism guides mate selection: Humans mate assortatively, as revealed by facial resemblance, following an algorithm of "self seeking like" | first1=Liliana | last1=Alvarez | first2=Klaus | last2=Jaffe | journal=Evolutionary Psychology | volume=2 | pages=177–194 | year=2004 | url=http://www.epjournal.net/filestore/ep02177194.pdf | doi=10.1177/147470490400200123 | doi-access=free | access-date=2011-02-08 | archive-date=2011-11-04 | archive-url=https://web.archive.org/web/20111104235428/http://www.epjournal.net/filestore/ep02177194.pdf | url-status=usurped }}</ref>

According to Morry's attraction-similarity model (2007), there is a lay belief that people with actual similarity produce initial attraction.<ref>{{cite journal | last1 = Morry | first1 = M. M. | year = 2007 | title = Relationship satisfaction as a predictor of perceived similarity among cross-sex friends: A test of the attraction-similarity model | journal = Journal of Social and Personal Relationships | volume = 24 | pages = 117–138 | doi=10.1177/0265407507072615| s2cid = 145548838 }}</ref> The perceived similarity is either self-serving, as in a friendship, or relationship-serving, as in a romantic relationship. In a 1963 study, [[Theodore Newcomb]] pointed out that people tend to change perceived similarity to obtain balance in a relationship.<ref name="newcomb63">{{cite journal | doi = 10.1037/h0041059 | pmid = 13938239 | last1 = Newcomb | first1 = T. M. | year = 1963 | title = Stabilities underlying changes in interpersonal attraction | journal = Journal of Abnormal and Social Psychology | volume = 66 | issue = 4 | pages = 376–386 }}</ref> Additionally, perceived but not actual similarity was found to predict interpersonal attraction during a face-to-face initial romantic encounter.<ref>{{cite journal | title=Perceived, not actual, similarity predicts initial attraction in a live romantic context: Evidence from the speed-dating paradigm | first1=Natasha | last1=Tidwell | first2=Paul | last2=Eastwick | first3=Eli | last3=Finkel | journal=Personal Relationships | volume=20 | issue=2 | pages=199–215 | date=June 2013 | url=https://static1.squarespace.com/static/504114b1e4b0b97fe5a520af/t/5365ab15e4b0d6ad5390a7d0/1399171861523/TidwellPR2013.pdf | doi=10.1111/j.1475-6811.2012.01405.x | access-date=2018-01-19 | archive-date=2017-08-13 | archive-url=https://web.archive.org/web/20170813035837/http://static1.squarespace.com/static/504114b1e4b0b97fe5a520af/t/5365ab15e4b0d6ad5390a7d0/1399171861523/TidwellPR2013.pdf | url-status=live }}</ref>

In a 1988 study, Lydon, Jamieson & Zanna suggest that interpersonal similarity and attraction are multidimensional constructs in which people are attracted to people similar to themselves in demographics, physical appearance, attitudes, interpersonal style, social and cultural background, personality, preferred interests and activities, and communication and social skills.<ref name=lydon1988>{{cite journal | last1 = Lydon | first1 = J. E. | last2 = Jamieson | first2 = D. W. | last3 = Zanna | first3 = M. P. | year = 1988 | title = Interpersonal similarity and the social and intellectual dimensions of first impressions | journal = Social Cognition | volume = 6 | issue = 4| pages = 269–286 | doi = 10.1521/soco.1988.6.4.269 }}</ref> Newcomb's earlier 1961 study on college-dorm roommates also suggested that individuals with shared backgrounds, academic achievements, attitudes, values, and political views typically became friends.{{citation needed|date=January 2018}}

==== Physical appearance ====
The [[matching hypothesis]] proposed by sociologist [[Erving Goffman]] suggests that people are more likely to form long standing relationships with those who are equally matched in social attributes, like physical attractiveness.<ref>{{cite book | last=Berkowitz | first=Leonard | year=1974 | title=Advances in Experimental Social Psychology, Volume 7 | isbn=978-0-12-015207-0 | pages=159–160| publisher=Elsevier Science & Technology Books }}</ref>{{page needed|date=January 2018}} The study by researchers [[Elaine Hatfield|Walster]] and Walster supported the matching hypothesis by showing that partners who were similar in terms of physical attractiveness expressed the most liking for each other.<ref>{{cite journal | last1=Berscheid | first1=Ellen | last2=Dion | first2=Karen | last3=Walster | first3=Elaine | last4=Walster | first4=G. William | title=Physical attractiveness and dating choice: A test of the matching hypothesis | journal=Journal of Experimental Social Psychology | date=1 March 1971 | url=http://www2.hawaii.edu/~elaineh/28.pdf | doi=10.1016/0022-1031(71)90065-5 | issn=0022-1031 | volume=7 | issue=2 | pages=173–189 | access-date=19 January 2018 | archive-date=23 September 2018 | archive-url=https://web.archive.org/web/20180923203049/http://www2.hawaii.edu/~elaineh/28.pdf | url-status=live }}</ref> Another study also found evidence that supported the matching hypothesis: photos of dating and engaged couples were rated in terms of attractiveness, and a definite tendency was found for couples of similar attractiveness to date or engage.<ref>{{cite journal | last1 = Murstein | first1 = Bernard I. | last2=Christy | first2=Patricia | title = Physical attractiveness and marriage adjustment in middle-aged couples | journal = Journal of Personality and Social Psychology | volume = 34 | pages = 537–542 | date= October 1976 | doi = 10.1037/0022-3514.34.4.537 | issue=4}}</ref> Several studies support this evidence of similar facial attractiveness. Penton-Voak, Perrett and Peirce (1999) found that subjects rated the pictures with their own face morphed into it as more attractive.<ref>{{cite journal | last1=Voak | first1=I. S. Penton- | last2=Perrett | first2=D. I. | last3=Peirce | first3=J. W. | title=Computer graphic studies of the role of facial similarity in judgements of attractiveness | journal=Current Psychology | date=1 March 1999 | url=http://www.psychology.nottingham.ac.uk/research/vision/jwp/papers/pentonvoak1999.pdf | doi=10.1007/s12144-999-1020-4 | issn=0737-8262 | volume=18 | issue=1 | pages=104–117 | citeseerx=10.1.1.485.1678 | s2cid=49321447 | access-date=19 January 2018 | archive-url=https://web.archive.org/web/20181111044353/http://www.psychology.nottingham.ac.uk/research/vision/jwp/papers/pentonvoak1999.pdf | archive-date=11 November 2018 | url-status=dead }}</ref> DeBruine (2002) demonstrated in her research how subjects entrusted more money to their opponents in a game play, when the opponents were presented as similar to them.<ref>{{cite journal | last=DeBruine | first=L. M. | title=Facial resemblance enhances trust | journal=Proceedings of the Royal Society B: Biological Sciences | date=7 July 2002 | doi=10.1098/rspb.2002.2034 | pmid=12079651 | pmc=1691034 | issn=0962-8452 | volume=269 | issue=1498 | pages=1307–1312}}</ref> Little, Burt & Perrett (2006) examined similarity in sight for married couples and found that the couples were assessed at the same age and level of attractiveness.<ref>{{cite journal | last1=Little | first1=Anthony C. | last2=Burt | first2=D. Michael | last3=Perrett | first3=David I. | title=Assortative mating for perceived facial personality traits | journal=Personality and Individual Differences | date=1 April 2006 | url=http://www.alittlelab.com/littlelab/pubs/Little_06_assortative_personality_PAID.pdf | doi=10.1016/j.paid.2005.09.016 | issn=0191-8869 | volume=40 | issue=5 | pages=973–984 | citeseerx=10.1.1.586.7971 | access-date=19 January 2018 | archive-date=20 January 2018 | archive-url=https://web.archive.org/web/20180120065625/http://www.alittlelab.com/littlelab/pubs/Little_06_assortative_personality_PAID.pdf | url-status=live }}</ref>

A [[speed dating|speed-dating]] experiment done on graduate students from Columbia University showed that although physical attractiveness is preferred in a potential partner, men show a greater preference for it than women.<ref>{{cite journal | last1 = Fisman | first1 = Raymond | last2 = Iyengar | first2 = Sheena S | last3 = Kamenica | first3 = Emir | last4 = Simonson | first4 = Itamar | title = Gender Differences in Mate Selection: Evidence from a Speed Dating Experiment | url = https://sheenaiyengar.com/wp-content/uploads/2016/08/2006-GenderDifferenceInMateSelection.pdf | journal = Quarterly Journal of Economics | volume = 121 | pages = 673–697 | date = 28 April 2006 | doi = 10.1162/qjec.2006.121.2.673 | issue = 2 | citeseerx = 10.1.1.176.2703 | access-date = 19 January 2018 | archive-url = https://web.archive.org/web/20170911205016/https://sheenaiyengar.com/wp-content/uploads/2016/08/2006-GenderDifferenceInMateSelection.pdf | archive-date = 11 September 2017 | url-status = dead }}</ref> However, more recent work suggests that sex differences in stated ideal partner-preferences for physical attractiveness disappear when examining actual preferences for real-life potential partners.<ref>{{cite journal | last1 = Luo | first1 = Shanhong | last2=Zhang | first2=Guangjian | title = What Leads to Romantic Attraction: Similarity, Reciprocity, Security, or Beauty? Evidence From a Speed-Dating Study | journal = Journal of Personality | volume = 77 | pages = 933–964 | date= August 2009 | doi = 10.1111/j.1467-6494.2009.00570.x | pmid = 19558447 | issue = 4}}</ref> For example, Eastwick and Finkel (2008) failed to find sex differences in the association between initial ratings of physical attractiveness and romantic interest in potential partners during a speed dating paradigm.<ref>{{cite journal | last1 = Eastwick | first1 = Paul | last2 = Finkel | first2 = Eli J. | title = Sex Differences in Mate Preferences Revisited: Do People Know What They Initially Desire in a Romantic Partner? | url = https://static1.squarespace.com/static/56c0eeaa7c65e465b5050feb/t/56c559aae707ebc71aa79244/1455774122666/EastwickFinkel2008_JPSP.pdf | journal = Journal of Personality and Social Psychology | volume = 94 | pages = 245–264 | date = February 2008 | doi = 10.1037/0022-3514.94.2.245 | issue = 2 | pmid = 18211175 | access-date = 2018-01-19 | archive-date = 2016-08-04 | archive-url = https://web.archive.org/web/20160804220827/http://static1.squarespace.com/static/56c0eeaa7c65e465b5050feb/t/56c559aae707ebc71aa79244/1455774122666/EastwickFinkel2008_JPSP.pdf | url-status = live }}</ref>

==== Quality of voice ====
In addition to physical looks, quality of voice has also been shown to enhance interpersonal attraction. Oguchi and Kikuchi (1997) had 25 female students from one university rank the level of vocal attraction, physical attraction, and overall interpersonal attraction of 4 male students from another university. Vocal and physical attractiveness had independent effects on overall interpersonal attraction. In a second part of the same study, these results were replicated in a larger sample of students for both genders (62 subjects, 20 males and 42 females with 16 target students, 8 males and 8 females).<ref>{{cite journal | last1 = Oguchi | first1 = Takashi | last2=Kikuchi | first2=Hiroto | title = Voice and Interpersonal Attraction | journal = Japanese Psychological Research | volume = 39 | pages = 56–61 | date= March 1997 | doi = 10.1111/1468-5884.00037 | issue = 2 | doi-access =  }}</ref> Similarly, Zuckerman, Miyake and Hodgins (1991) found that both vocal and physical attractiveness contributed significantly to observers' ratings of targets for general attractiveness.<ref>{{cite journal | last1 = Zuckerman | first1 = Miron | last2=Miyake | first2=Kunitate | last3=Hodgins | first3=Holley S. | title = Cross-channel effects of vocal and physical attractiveness and their implications for interpersonal perception. | journal = Journal of Personality and Social Psychology | volume = 60 | pages = 545–554 | date= April 1991 | issue = 4 | doi=10.1037/0022-3514.60.4.545| pmid = 2037966 }}</ref> These results suggest that when people evaluate one's voice as attractive, they also tend to evaluate that person as physically attractive.

==== Attitudes ====
Based on [[cognitive consistency]] theories, difference in attitudes and interests can lead to dislike and avoidance whereas similarity in attitudes promotes social attraction.<ref name=singh2000>{{cite journal | doi = 10.1348/014466600164426 | last1 = Singh | first1 = R. | last2 = Ho | first2 = S. Y. | year = 2000 | title = Attitudes and attraction: A new test of the attraction, repulsion and similarity-dissimilarity asymmetry hypotheses | journal = British Journal of Social Psychology | volume = 39 | issue = 2| pages = 197–211 | pmid = 10907095 }}</ref><ref name=byrne1968>{{cite journal | doi = 10.1111/j.1467-6494.1968.tb01473.x | last1 = Byrne | first1 = D. | last2 = London | first2 = O. | last3 = Reeves | first3 = K. | year = 1968 | title = The effects of physical attractiveness, sex, and attitude similarity on interpersonal attraction | journal = Journal of Personality | volume = 36 | issue = 2| pages = 259–271 | pmid = 5660731 }}</ref> Miller (1972) pointed out that attitude similarity activates the perceived attractiveness and favorability information from each other, whereas dissimilarity would reduce the impact of these cues.<ref name=miller1972>{{cite journal | last1 = Miller | first1 = A. G. | year = 1972 | title = Effect of attitude similarity-dissimilarity on the utilization of additional stimulus inputs in judgments of interpersonal attraction | journal = [[Psychonomic Science]] | volume = 26 | issue = 4| pages = 199–203 | doi=10.3758/bf03328593| doi-access = free }}</ref>

The studies by Jamieson, Lydon and Zanna (1987–88) showed that attitude similarity could predict how people evaluate their respect for each other, and also predict social and intellectual first impressions – the former by activity preference similarity and the latter by value-based attitude similarity.<ref name=jamieson1986>{{cite journal | doi = 10.1037/0022-3514.53.6.1052 | last1 = Jamieson | first1 = D. W. Lydon | last2 = Zanna | first2 = M. P. | last3 = Zanna | year = 1987 | first3 = Mark P. | title = Attitude and activity preference similarity: Differential bases of interpersonal attraction for low and high self-monitors | journal = Journal of Personality and Social Psychology | volume = 53 | issue = 6| pages = 1052–1060 }}</ref> In intergroup comparisons, high attitude-similarity would lead to homogeneity among in-group members whereas low attitude-similarity would lead to diversity among in-group members, promoting social attraction and achieving high group performance in different tasks.<ref name=hahn1999>{{cite journal | last1 = Hahn | first1 = D. | last2 = Hwang | first2 = S. | year = 1999 | title = Test of similarity-attraction hypothesis in group performance situation | journal = Korean Journal of Social & Personality Psychology | volume = 13 | issue = 1| pages = 255–275 }}</ref>

Although attitude similarity and attraction are linearly related, attraction may not contribute significantly to attitude change.<ref>{{cite journal | doi = 10.1037/h0028429 | last1 = Simons | first1 = H. W. | last2 = Berkowitz | first2 = N. N. | last3 = Moyer | first3 = R. J. | year = 1970 | title = Similarity, credibility, and attitude change: A review and a theory | journal = Psychological Bulletin | volume = 73 | issue = 1| pages = 1–16 }}</ref>

====Other social and cultural aspects====
Byrne, Clore and Worchel (1966) suggested that people with similar economic status are likely to be attracted to each other.<ref name=byrne1966>{{cite journal | doi = 10.1037/h0023559 | last1 = Byrne | first1 = D. | last2 = Clore | first2 = G. L. J. | last3 = Worchel | first3 = P. | year = 1966 | title = Effect of economic similarity-dissimilarity on interpersonal attraction | journal = Journal of Personality and Social Psychology | volume = 4 | issue = 2| pages = 220–224 }}</ref> Buss & Barnes (1986) also found that people prefer their romantic partners to be similar in certain demographic characteristics, including religious background, political orientation and [[socio-economic status]].<ref>*{{cite journal | doi = 10.1037/0022-3514.50.3.559 | last1 = Buss | first1 = D. M. | last2 = Barnes | first2 = M. | year = 1986 | title = Preferences in human mate selection | journal = [[Journal of Personality and Social Psychology]] | volume = 50 | issue = 3 | pages = 559–570 | url = https://www.researchgate.net/publication/232444193 | access-date = 2019-01-27 | archive-date = 2022-01-25 | archive-url = https://web.archive.org/web/20220125080049/https://www.researchgate.net/publication/232444193_Preferences_in_Human_Mate_Selection | url-status = live }}</ref>

Researchers have shown that interpersonal attraction was positively correlated to [[Personality psychology|personality]] similarity.<ref>{{cite journal | doi = 10.1007/BF02087933 | pmid = 24318017 | last1 = Goldman | first1 = J. A. | last2 = Rosenzweig | first2 = C. M. | last3 = Lutter | first3 = A. D. | year = 1980 | title = Effect of similarity of ego identity status on interpersonal attraction | journal = [[Journal of Youth and Adolescence]] | volume = 9 | issue = 2| pages = 153–162 | s2cid = 10589621 }}</ref> People are inclined to desire romantic partners who are similar to themselves on agreeableness, conscientiousness, extroversion, emotional stability, openness to experience,<ref>{{cite journal | doi = 10.1111/j.1467-6494.1997.tb00531.x | last1 = Botwin | first1 = M. D. | last2 = Buss | first2 = D. M. | last3 = Shackelford | first3 = T. K. | year = 1997 | title = Personality and mate preferences: Five factors in mate selection and marital satisfaction | journal = [[Journal of Personality]] | volume = 65 | issue = 1| pages = 107–136 | pmid = 9143146 | s2cid = 15643556 | url = https://pdfs.semanticscholar.org/5158/d9f36fb17bc37171ae7ecb6fc7d26493805f.pdf | archive-url = https://web.archive.org/web/20180119120204/https://pdfs.semanticscholar.org/5158/d9f36fb17bc37171ae7ecb6fc7d26493805f.pdf | url-status = dead | archive-date = 2018-01-19 }}</ref> and attachment style.<ref>{{cite journal | doi = 10.1037/0022-3514.85.4.709 | last1 = Klohnen | first1 = E. C. | last2 = Luo | first2 = S. | year = 2003 | title = Interpersonal attraction and personality: What is attractive – self similarity, ideal similarity, complementarity, or attachment security? | journal = Journal of Personality and Social Psychology | volume = 85 | issue = 4| pages = 709–722 | pmid = 14561124 }}</ref>

Activity similarity was especially predictive of liking judgments, which affects the judgments of attraction.<ref name=lydon1988 /> According to the post-conversation measures of social attraction, tactical similarity was positively correlated with partner satisfaction and global competence ratings, but was uncorrelated with the opinion change and perceived persuasiveness measures.<ref>{{cite journal | last1 = Waldron | first1 = V. R. | last2 = Applegate | first2 = J. L. | year = 1998 | title = Similarity in the use of person-centered tactics: Effects on social attraction and persuasiveness in dyadic verbal disagreements | journal = Communication Reports | volume = 11 | issue = 2| pages = 155–165 | doi = 10.1080/08934219809367697 }}</ref>

When checking similar variables they were also seen as more similar on a number of personality characteristics. This study found that the length of the average relationship was related to perceptions of similarity; the couples who were together longer were seen as more equal. This effect can be attributed to the fact that when time passes by couples become more alike through shared experiences, or that couples that are alike stay together longer.<ref>{{cite journal | last1=Zajonc | first1=R. B. | last2=Adelmann | first2=Pamela K. | last3=Murphy | first3=Sheila T. | last4=Niedenthal | first4=Paula M. | title=Convergence in the physical appearance of spouses | journal=Motivation and Emotion | date=1 December 1987 | url=https://deepblue.lib.umich.edu/bitstream/handle/2027.42/45361/11031_2004_Article_BF00992848.pdf?sequence=1&isAllowed=y | doi=10.1007/BF00992848 | issn=0146-7239 | volume=11 | issue=4 | pages=335–346 | hdl=2027.42/45361 | s2cid=16501311 | hdl-access=free | access-date=19 January 2018 | archive-date=5 November 2020 | archive-url=https://web.archive.org/web/20201105144717/https://deepblue.lib.umich.edu/bitstream/handle/2027.42/45361/11031_2004_Article_BF00992848.pdf?sequence=1&isAllowed=y | url-status=live }}</ref>

Similarity has effects on starting a relationship by initial attraction to know each other. It is shown that high attitude similarity resulted in a significant increase in initial attraction to the target person and high attitude dissimilarity resulted in a decrease of initial attraction.<ref>{{cite journal | last1 = Gutkin | first1 = T. B. | last2 = Gridley | first2 = G. C. | last3 = Wendt | first3 = J. M. | year = 1976 | title = The effect of initial attraction and attitude similarity-dissimilarity on interpersonal attraction | journal = Cornell Journal of Social Relations | volume = 11 | issue = 2| pages = 153–160 }}</ref><ref>{{cite journal | last1 = Kaplan | first1 = M. F. | last2 = Olczak | first2 = P. V. | year = 1971 | title = Attraction toward another as a function of similarity and commonality of attitudes | journal = [[Psychological Reports]] | volume = 28 | issue = 2| pages = 515–521 | doi = 10.2466/pr0.1971.28.2.515 | s2cid = 143796470 }}</ref> Similarity also promotes relationship commitment.<ref>{{Cite web|title=Relationship-Commitment – Articles, Blogs, Comments, Discussions, Postings {{!}} ispace1|url=https://www.ispace1.com/Relationship-Commitment|access-date=2020-11-16|website=ispace1.com|language=en-us|archive-date=2020-11-28|archive-url=https://web.archive.org/web/20201128220646/https://www.ispace1.com/Relationship-Commitment|url-status=live}}</ref> Study on heterosexual dating couples found that similarity in intrinsic values of the couple was linked to relationship commitment and stability.<ref>{{cite journal | doi = 10.1177/01461672972310011 | last1 = Kurdek | first1 = L. A. | last2 = Schnopp-Wyatt | first2 = D. | year = 1997 | title = Predicting relationship commitment and relationship stability from both partners' relationship values: Evidence from heterosexual dating couples | journal = Personality and Social Psychology Bulletin | volume = 23 | issue = 10| pages = 1111–1119 | s2cid = 145255443 }}</ref>

Social homogamy refers to "passive, indirect effects on spousal similarity". The result showed that age and education level are crucial in affecting the mate preference. Because people with similar age study and interact more in the same form of the school, propinquity effect (i.e., the tendency of people to meet and spend time with those who share the common characteristics) plays a significant impact in spousal similarity. Convergence refers to an increasing similarity with time. Although the previous research showed that there is a greater effect on attitude and value than on personality traits, however, it is found that initial assortment (i.e., similarity within couples at the beginning of marriage) rather than convergence, plays a crucial role in explaining spousal similarity.<ref>{{cite journal | doi = 10.1111/j.0022-3506.2004.00289.x | last1 = Watson | first1 = D. | last2 = Klohnen | first2 = E. C. | last3 = Casillas | first3 = A. | last4 = Nus | first4 = S. E. | last5 = Haig | first5 = J. | last6 = Berry | first6 = D. S. | year = 2004 | title = Match makers and deal breakers: Analyses of assortative mating in newlywed couples | journal = Journal of Personality | volume = 72 | issue = 5| pages = 1029–68 | pmid = 15335336 | citeseerx = 10.1.1.470.7636 }}</ref>

Active assortment refers to direct effects on choosing someone similar to oneself in mating preferences. The data showed that there is a greater effect on political and religious attitudes than on personality traits. A follow-up issue on the reason of the finding was raised. The concepts of idiosyncratic (i.e. different individuals have different mate preferences) and consensual (i.e. a consensus of preference on some prospective mates to others) in mate preference. The data showed that mate preference on political and religious bases tend to be idiosyncratic, for example, a Catholic would be more likely to choose a mate who is also a Catholic, as opposed to a Buddhist. Such idiosyncratic preferences produce a high level of active assortment which plays a vital role in affecting spousal similarity. In summary, active assortment plays a large role, whereas convergence has little evidence on showing such effect.{{citation needed|date=January 2018}}