Bisexuality

Abstract

Bisexuality, which the Medical Subject Headings thesaurus classifies under sexuality, is the pattern of sexual or romantic attraction toward more than one sex. Cognitive psychology studies it less as an identity label than as a measurement problem: it occupies the middle of the Kinsey continuum, the region a single orientation axis most easily erases, and it is the test case that decides whether one dimension or two are needed to describe orientation. This article reviews how bisexuality is defined and measured, the long controversy over whether a distinct bisexual pattern of genital arousal exists and its recent resolution, the evidence that bisexual attraction can be among the most stable orientation patterns over time, and the component dissociation that makes measured prevalence depend on whether attraction, behavior, or identity is counted.

Keywords: bisexuality, sexual orientation, Kinsey scale, category-specific arousal, bisexual erasure

Introduction

Bisexuality is the pattern of sexual or romantic attraction toward more than one sex (Bailey et al., 2016). As a form of sexual orientation it names the broad middle of the orientation spectrum rather than one of its two poles, and that location is exactly what makes it analytically useful. Cognitive psychology approaches bisexuality not as a social category to be defended or doubted but as the case that stresses every measurement model: an instrument that handles the heterosexual and homosexual ends cleanly can still mishandle the middle, and how it does so reveals the instrument's assumptions.

Two features give bisexuality its special status in orientation research. First, it sits where a one-dimensional scale is weakest. On the Kinsey continuum a bisexual person occupies the midrange, but a single number cannot distinguish strong attraction to both sexes from weak attraction to either, so the summary measure that works at the ends becomes ambiguous in the middle (Kinsey et al., 1948). Second, its components dissociate especially sharply: far more people report some attraction to more than one sex than ever adopt the label, so measured bisexuality depends heavily on whether attraction, behavior, or identity is counted (Savin-Williams & Ream, 2007).

The Medical Subject Headings thesaurus indexes Bisexuality beneath Sexuality in its classification of behavior. That placement is a retrieval convenience, not a theoretical claim about kinds of people; this article uses it only to situate bisexuality among related orientations and otherwise treats the psychology on its own terms, beginning with how the pattern is measured.

Measuring Bisexuality

Bisexuality became a measurable idea the moment orientation was treated as graded rather than categorical. Kinsey, Pomeroy, and Martin (1948) placed people on a seven-point continuum from exclusively heterosexual (0) to exclusively homosexual (6), and in doing so made the bisexual middle — roughly ratings 2 through 4 — a region that could be described rather than a contradiction to be explained away. Yet the single axis that rescued bisexuality also obscures it. A midpoint rating of 3 can mean strong attraction to both sexes or faint attraction to either, because one number cannot separate the amount of same-sex attraction from the amount of other-sex attraction; the scale that is informative at its ends is ambiguous at its center.

Klein, Sepekoff, and Wolf (1985) built the instrument most associated with taking bisexuality seriously as a multidimensional profile. Their Sexual Orientation Grid rates seven variables — attraction, behavior, fantasy, emotional preference, social preference, lifestyle, and self-identification — each separately for the past, the present, and the ideal. For a bisexual person these cells routinely disagree: predominantly other-sex behavior can coexist with substantial same-sex fantasy, and a present identity can differ from past experience. The grid makes the dissociation explicit instead of averaging it into a single compromised number.

Whether orientation needs one dimension or two is in the end an empirical question, and bisexuality is the case that answers it. Lippa (2020) analyzed interest, personality, and sexual traits across orientation groups and asked whether variation is better captured by one bipolar hetero–homosexual axis or by two partly independent dimensions — same-sex and other-sex attraction considered separately. The two-dimensional model is needed precisely to represent bisexual patterns: on a single bipolar axis, high attraction to both sexes is indistinguishable from low attraction to both, whereas two axes place the former in a high–high corner of its own. Figure 1 shows the collapse directly.

The first demonstration makes the contrast interactive, letting the reader set same-sex and other-sex attraction independently and watch where the single Kinsey axis collapses them.

The Arousal Controversy

No question about bisexuality has been more contested than whether it shows up in the body. The relevant construct is category-specificity: the degree to which genital arousal is selective for one sex. Chivers and colleagues (2010) meta-analyzed studies recording both self-reported and genital arousal and found that, in men, the two agree closely and genital response is category-specific, tracking the sex a man says he is attracted to. That backdrop set up a sharp prediction — a bisexual man should show substantial genital arousal to both sexes — and the first test appeared to fail it.

Rieger, Chivers, and Bailey (2005) measured the genital arousal of men who identified as bisexual and reported that, as a group, their arousal tended to resemble that of homosexual men rather than showing the symmetric response their identity implied. The result was widely read as evidence that male bisexual arousal might not exist, a conclusion that attracted both scientific and public controversy. But the apparent absence proved to be an artifact of whom the studies recruited. Rosenthal and colleagues (2011) revisited the question with men selected for genuine bisexual attraction histories — requiring romantic and sexual experience with both sexes rather than only a self-applied label — and found the expected bisexual arousal pattern: substantial genital response to both male and female stimuli.

The resolution came at scale. Jabbour and colleagues (2020) pooled data across studies with stringently sampled bisexual men and found robust evidence of a bisexual arousal pattern — greater genital and self-reported response to both sexes than monosexual men show. The episode is a lesson in method: the construct was real throughout, and the early null measured a sampling decision rather than the phenomenon. The second demonstration models exactly this dependence, letting the reader tighten the sampling criterion and watch a bisexual arousal pattern emerge from what lax recruitment had hidden.

Prevalence, Stability, and Fluidity

How common bisexuality is depends entirely on what is counted. Savin-Williams and Ream (2007) found that orientation's components dissociate: many more adolescents and young adults report some attraction to more than one sex than report bisexual behavior, and more report either than adopt a bisexual identity. Because the components narrow in that order — attraction broadest, identity narrowest — a prevalence estimate is really a statement about which component the researcher chose, and a headline figure for “how many people are bisexual” is underspecified until that choice is named.

Stability is the second surprise. The intuition that bisexuality is a transitional stage on the way to a “real” monosexual orientation was tested directly and did not survive. Diamond (2008) followed women over ten years and found that a bisexual pattern of attraction was not a way station but one of the most stable patterns in the sample — women with bisexual attractions tended to retain attractions to both sexes, even as the labels they used changed. Bisexuality, on this evidence, is a durable orientation rather than a phase.

Stability and change nonetheless coexist. Mock and Eibach (2012) reported over a ten-year adult span that most people's identity was stable but that change was concentrated among those not exclusively heterosexual, and Diamond (2016) argued that sexual fluidity — situation-dependent change layered on an underlying orientation — is a general human capacity rather than a female peculiarity. For bisexual people this means the label can shift (to or from “fluid,” “queer,” “lesbian,” or “gay”) while the underlying capacity for attraction to more than one sex persists. The third demonstration makes the component dissociation visible, letting the reader see how the share counted as bisexual shrinks as the criterion moves from attraction to behavior to identity.

Worked Example

Consider one person assessed with the tools above: a man who reports strong attraction to women and moderate but real attraction to men, whose sexual history is almost entirely with women, and who identifies as heterosexual. Is he bisexual? The honest answer is that the question is incomplete until a component is named, and the three components give three answers.

Attraction places him squarely in the bisexual range: substantial response to both sexes, the high–high corner a two-dimensional model represents and a single Kinsey number near 1–2 would understate (Lippa, 2020). Behavior reads as effectively heterosexual, because an enacted history reflects opportunity and circumstance as much as desire, and would erase the same-sex attraction his own report records (Kinsey et al., 1948). Identity also reads “heterosexual,” but identity is the component least tightly bound to attraction and most shaped by social context, so it is the least diagnostic of the three (Savin-Williams & Ream, 2007). Table 1 lays the three construals side by side.

The example makes the article's point exact. There is one person, and the disagreement among his three placements is not error; it is the predictable output of measuring dissociable components. A single index would have to choose one and discard the rest, and whichever it chose, it would either count him bisexual or erase his bisexuality entirely — which is why specifying the component, and preferring instruments that keep the components apart, is a prerequisite for measuring bisexuality at all (Klein et al., 1985).

Discussion

The cognitive psychology of bisexuality is, at its core, a running argument about measurement. Bisexuality is where the convenient one-dimensional picture of orientation breaks down, because the midpoint of a bipolar scale confounds strong attraction to both sexes with weak attraction to either (Kinsey et al., 1948), and only a multidimensional or two-dimensional treatment keeps the pattern distinct (Klein et al., 1985; Lippa, 2020). The arousal controversy tells the same story in the physiological register: the apparent absence of a male bisexual response reflected who was recruited, and stringent sampling recovered the pattern that weaker designs had hidden (Rieger et al., 2005; Rosenthal et al., 2011; Jabbour et al., 2020).

Integrating these findings dissolves several apparent paradoxes. A person can be “bisexual in attraction but heterosexual in behavior” without contradiction once components are kept distinct; bisexuality can be both durable and accompanied by shifting labels once stability is seen to vary by component, with attraction more stable than identity (Diamond, 2008; Mock & Eibach, 2012); and the wide gap between attraction-defined and identity-defined prevalence is expected rather than anomalous (Savin-Williams & Ream, 2007). The comprehensive review by Bailey and colleagues (2016) reaches the same integrative conclusion: the orientation it describes is real, early-emerging, and substantially stable, and bisexuality is a genuine region of it rather than an unstable boundary between two categories.

None of this reduces bisexuality to any single measure. The point of the cognitive analysis is the opposite: by specifying which component is in view and how it is assessed, it explains why summaries that pick one index disagree about who counts as bisexual, and why that disagreement is the expected result of a multidimensional object rather than evidence that bisexuality is not real.

Current Directions

The most consequential recent movement is away from arguing over whether bisexuality exists and toward documenting the health and social circumstances of bisexual people. The central finding is a disparity. Ross and colleagues (2018) conducted a systematic review and meta-analysis comparing rates of depression and anxiety across sexual-orientation groups and found that bisexual people reported elevated rates not only relative to heterosexual people but, on several measures, relative to gay and lesbian people as well. The result reframes a measurement debate as a question about minority stress: the proposed explanation is that bisexual people face distinctive stressors — including invalidation of their orientation from both heterosexual and gay or lesbian communities, sometimes termed bisexual erasure — that compound the general strain of a minority orientation.

That reframing turns the measurement themes of this article into a research agenda with direct consequences. If attraction-defined bisexuality is far more common than identity-defined bisexuality (Savin-Williams & Ream, 2007), then studies that recruit only self-identified bisexual people may describe a small and unrepresentative slice of a much larger population, and health estimates built on that slice may mislead. The confirmation of a genuine bisexual arousal pattern under careful sampling (Jabbour et al., 2020) and the evidence that bisexual attraction can be highly stable (Diamond, 2008) together undercut the “not a real orientation” framing that has itself been identified as a source of the stress. The open questions now concern how to measure bisexuality in ways that neither erase nor inflate it, and how the measurement choice interacts with the health disparities the recent literature documents.

Common Misconceptions

“Bisexuality is just a phase on the way to being gay or straight.”

A ten-year longitudinal study found that a bisexual pattern of attraction was among the most stable in the sample, not a transitional stage; the labels people used changed more than their underlying attractions did (Diamond, 2008).

“Science showed bisexual men are not really bisexual.”

An early arousal study that failed to find a distinct male bisexual pattern was overturned by research using stricter sampling, which found robust genital and self-reported evidence of bisexual arousal (Rosenthal et al., 2011; Jabbour et al., 2020).

“A point in the middle of the Kinsey scale means someone is only mildly attracted to either sex.”

A single midpoint rating cannot distinguish strong attraction to both sexes from weak attraction to either; separating same-sex and other-sex attraction into two dimensions is what tells them apart (Lippa, 2020).

“There is one true number for how many people are bisexual.”

Measured prevalence depends on the component counted: far more people report attraction to more than one sex than report bisexual behavior or adopt a bisexual identity, so any estimate must name the component it used (Savin-Williams & Ream, 2007).

Glossary

Attraction.

The felt pull of sexual or romantic interest toward a sex; the component of orientation that defines bisexuality and the one on which it is most common.

Bisexual erasure.

The tendency to deny, minimize, or re-label bisexuality — whether by a measurement instrument or a social community — treating it as confusion or a phase rather than a distinct orientation.

Bisexuality.

The pattern of sexual or romantic attraction toward more than one sex; in cognitive psychology, the midrange of the orientation spectrum rather than a boundary between two categories.

Category-specificity.

The degree to which genital arousal is selective for one sex; a bisexual pattern is defined by substantial response to both sexes rather than to one.

Component (of orientation).

One of the separable aspects of orientation — attraction, arousal, fantasy, behavior, or identity — that are correlated but can give different answers for one person.

Concordance (of components).

The degree to which a person's separable orientation components — attraction, behavior, identity — agree; bisexuality is marked by frequent discordance, where the components give different answers for one person.

Dimensional model.

A representation of orientation using two independent axes — same-sex and other-sex attraction rated separately — rather than one bipolar axis, which is what distinguishes strong attraction to both sexes from weak attraction to either.

Kinsey scale.

A seven-point continuum from exclusively heterosexual (0) to exclusively homosexual (6); bisexuality occupies its midrange, roughly ratings 2 through 4.

Klein Sexual Orientation Grid.

A multidimensional instrument rating seven variables across past, present, and ideal, built to represent bisexuality as a profile rather than a single number.

Minority stress.

The excess strain borne by a stigmatized group; proposed to explain elevated depression and anxiety among bisexual people, including stress from invalidation by both heterosexual and gay or lesbian communities.

Monosexual.

Attracted to a single sex (exclusively heterosexual or exclusively homosexual); the contrast class against which a bisexual pattern is defined.

Sexual fluidity.

Situation- and relationship-dependent change in attraction or identity layered on an underlying orientation; for bisexual people, the labels can shift while attraction to more than one sex persists.

Sexuality.

The multidimensional construct — attraction, arousal, fantasy, behavior, and identity — under which MeSH classifies bisexuality and its sibling orientations.

Stability.

The tendency of an orientation component to persist across time; a bisexual pattern of attraction is, on longitudinal evidence, among the more stable rather than a transitional stage.

Key Researchers

J. Michael Bailey

is a professor of psychology at Northwestern University whose work on the arousal correlates and measurement of orientation includes the studies that first questioned and later confirmed a distinct male bisexual arousal pattern.

Faculty page - Google Scholar - Wikipedia

Meredith L. Chivers

is a professor of psychology at Queen's University whose research on the category-specificity of arousal established the sex difference that frames how bisexual arousal patterns are read.

ORCID - Faculty page - Wikipedia

Lisa M. Diamond

is a distinguished professor of psychology and gender studies at the University of Utah whose decade-long longitudinal research showed that a bisexual pattern of attraction can be among the most stable over time rather than a transitional stage.

Faculty page - Wikipedia

Alfred C. Kinsey

(1894–1956) founded the Institute for Sex Research at Indiana University and devised the graded scale of orientation on which bisexuality occupies the measurable middle.

Wikipedia

Fritz Klein

(1932–2006) was a psychiatrist and the founder of what became the American Institute of Bisexuality whose Sexual Orientation Grid formalized bisexuality as a multidimensional profile rather than a single rating.

Wikipedia

Richard A. Lippa

is a professor emeritus of psychology at California State University, Fullerton whose analyses asked whether two independent dimensions, rather than one bipolar axis, are needed to represent bisexual patterns of attraction.

Faculty page

Gerulf Rieger

is a researcher in the Department of Psychology at the University of Essex whose first-authored 2005 study of bisexual men's genital arousal catalyzed the measurement debate that later work resolved.

Google Scholar

Ritch C. Savin-Williams

is a professor emeritus of developmental psychology at Cornell University whose research on the prevalence and stability of orientation's components documented how far attraction-defined bisexuality outnumbers identity-defined bisexuality.

ORCID - Faculty page - Google Scholar

Frequently Asked Questions

What is bisexuality?

In research, bisexuality is the pattern of sexual or romantic attraction toward more than one sex. Cognitive psychology treats it as a region of the orientation spectrum rather than a boundary between categories, and studies it mainly as a measurement problem: how to describe the middle of the orientation range without erasing it (Bailey et al., 2016).

Where does bisexuality fall on the Kinsey scale?

In the midrange — roughly ratings 2 through 4 on the 0-to-6 continuum (Kinsey et al., 1948). But a single midpoint number is ambiguous, because it cannot distinguish strong attraction to both sexes from weak attraction to either; separating same-sex and other-sex attraction into two dimensions is what resolves the ambiguity (Lippa, 2020).

Is male bisexuality real?

Yes. An early study failed to find a distinct bisexual pattern of male genital arousal (Rieger et al., 2005), but research using stricter sampling — men with genuine bisexual attraction histories — found the expected pattern (Rosenthal et al., 2011), and a large pooled study confirmed robust evidence for it (Jabbour et al., 2020). The earlier null reflected recruitment, not the absence of the orientation.

Is bisexuality just a phase?

The evidence says no. A ten-year longitudinal study found that a bisexual pattern of attraction was one of the most stable in the sample; women with bisexual attractions tended to keep them, even when the labels they used changed (Diamond, 2008). Bisexuality is a durable orientation, not a way station.

Why do estimates of how many people are bisexual vary so much?

Because the number depends on which component is counted. Far more people report attraction to more than one sex than report bisexual behavior, and more report either than adopt a bisexual identity (Savin-Williams & Ream, 2007). An estimate is underspecified until it names whether it is counting attraction, behavior, or identity.

What is the difference between bisexual attraction, behavior, and identity?

They are correlated but dissociable components. A person can feel attraction to more than one sex, act on it with only one sex, and identify as something other than bisexual — all at once. The Klein Sexual Orientation Grid rates these separately precisely because they can disagree (Klein et al., 1985).

Can a bisexual person's orientation change over time?

The label can shift while the underlying attraction persists. Sexual fluidity — situation-dependent change layered on an underlying orientation — is a general human capacity (Diamond, 2016), and identity changes more than attraction does, concentrated among people who are not exclusively heterosexual (Mock & Eibach, 2012).

Why do bisexual people report worse mental health?

A systematic review and meta-analysis found elevated rates of depression and anxiety among bisexual people, on several measures exceeding those of gay and lesbian people (Ross et al., 2018). The proposed explanation is minority stress compounded by distinctive stressors, including the invalidation of bisexuality by both heterosexual and gay or lesbian communities.

References