Factors Affecting Attraction (AQA A-Level Psychology): Revision Notes

Philtre Theory

Philtre theory is an explanation of relationship formation developed to understand how romantic partnerships develop. The theory proposes that several factors work like philtres to progressively narrow down the vast pool of potential partners to a much smaller, more realistic group of people we might actually form relationships with.

Key study: Kerckhoff and Davis (1962)

Kerckhoff and Davis, Philtre theory, 1962

Participants: Student couples in both short-term (less than 18 months) and long-term relationships

Aim: To compare the attitudes and personalities of couples and explain how romantic relationships form and develop

Procedure: The researchers compared couples who had been together for different lengths of time to identify which factors were most important at different relationship stages

Evaluation: Strengths

• The theory demonstrates face validity as it matches most people's experience of relationship formation
• Research support from Peter Winch (1988) found that similarities in personality, interests and attitudes are typical in early relationship stages
• The concept that different factors matter at different stages makes logical sense

Evaluation: Weaknesses

• Many replication studies have failed to support the original findings, suggesting limited reliability
• The 18-month cut-off point for distinguishing short-term from long-term relationships may be arbitrary
• The theory was developed on heterosexual couples in individualist cultures, limiting its generalisability

The three levels of philtres

Social demography (1st level philtre)

Social demography refers to the demographic characteristics that influence whether potential partners will actually meet each other. These factors include geographical location (proximity), social class, education level, ethnic group, religion, and age.

The key concept here is proximity - we are much more likely to meet and form relationships with people who live nearby, attend the same educational institutions, or work in similar environments. This creates accessibility - it requires minimal effort to encounter and interact with people who share our social circumstances.

Most people end up in relationships with others who share characteristics like ethnicity, religious beliefs, educational background and social class, as these shared similarities are often found attractive and provide common ground for relationship development.

Similarity in attitudes (2nd level philtre)

Partners often share important beliefs and values, particularly because the field of potential partners has already been narrowed by social demographic factors. Similarity in attitudes becomes especially important for couples in the earlier stages of relationships (those together for less than 18 months according to Kerckhoff and Davis).

Early relationships require partners to agree on basic values and the things that really matter to them. This shared foundation encourages greater communication and promotes self-disclosure between partners. Research consistently shows that we find similarity attractive, at least initially.

The importance of attitudinal similarity in early relationships makes evolutionary sense, as shared values suggest compatibility and reduce the likelihood of major conflicts during the vulnerable initial stages of relationship formation.

Complementarity (3rd level philtre)

The third philtre operates on the principle that romantic partners can meet each other's psychological needs through complementarity. Two people complement each other when they possess traits that the other person lacks, creating a sense of wholeness when they are together.

Complementarity becomes attractive because it allows two people to feel they form a complete unit together, which adds depth and stability to the relationship. This philtre suggests that whilst similarity draws people together initially, longer-term relationship success may depend more on how well partners can balance each other's characteristics and meet each other's needs.

Evaluation

Support from research evidence

Philtre theory benefits from research support and has good face validity - it aligns with most people's actual experience of how relationships develop. Peter Winch (1988) provided evidence supporting the theory by finding that similarities in personality, interests and attitudes between partners are indeed typical of the earliest relationship stages.

The research also supports the matching hypothesis concept, though not just in terms of physical attractiveness. Among couples who had been happily married for several years, complementarity of needs proved more important than similarity, exactly as Winch's research predicted and as philtre theory suggests.

Failure to replicate

The researchers' decision to use an 18-month cut-off point to distinguish between short-term and long-term relationships was somewhat arbitrary. This assumed that couples together longer than 18 months were automatically more committed and had deeper relationships, which may not always be accurate.

These replication issues raise questions about applying philtre theory to relationships beyond heterosexual couples in individualist cultures, and suggest the theory may have limited cross-cultural validity.

Direction of cause and effect

Philtre theory assumes that people are initially attracted to each other because they share demographic and attitudinal similarities. However, research evidence suggests this direction of causality may be incorrect.

Similarly, Davis and Rusbult (2001) discovered an attitude alignment effect in longer-term relationships, where romantic partners gradually bring their attitudes into line with each other's over time. Again, this indicates that similarity develops as a consequence of the relationship rather than being its foundation.

These findings contradict philtre theory's predictions about the causal role of similarity in relationship formation.

Lack of temporal validity

The rise of online dating has dramatically changed how romantic relationships begin, potentially reducing the importance of social demographic variables that philtre theory emphasises. Technologies like internet dating sites and mobile apps such as Tinder have made meeting potential partners much easier, enabling people to pursue relationships with individuals outside their usual demographic boundaries.

Similarity or complementarity debate

Recent research has challenged philtre theory's claim that complementarity becomes more important than similarity in longer-term relationships. Anderson et al. (2003) found that similarity actually increases over time, suggesting complementarity may not be a common feature of successful long-term relationships.

Gruber-Baldini et al. (1995) conducted a 14-year longitudinal study of married couples and found that similarities between spouses in intellectual abilities and attitudinal flexibility increased over the study period. These findings undermine the validity of the third philtre and suggest that similarity, rather than complementarity, may be what sustains long-term relationships.

This research raises questions about whether the theory accurately describes how relationships develop beyond the initial stages, and whether the emphasis on complementarity in long-term relationships is misplaced.