“But what the hell is it for?” asked Alan Baddeley (1988) about human memory. From
an adaptive perspective, our mnemonic systems ought to be calibrated to retain information
of high adaptive value i.e., that which promotes individual survival and reproduction
(Tooby and Cosmides, 1989; Klein et al., 2002). To address the former, the last decade
has seen the emergence of an extensive functionalist literature providing evidence
of a survival mode in episodic memory (for a review, see Nairne and Pandeirada, 2016).
These experiments characterize memory as the process of a general survival optimization
system, attuned toward relevant stimulus.
Regarding the latter part of nature's criterion, labs have examined the role of memory
in courtship by exploring how contextual factors including jealousy (Maner et al.,
2009), relationship status (Karremans et al., 2011), and primed infidelity (Schutzwohl
and Koch, 2004) influence recall. Furthermore, generalized memory enhancements have
been observed in response to attractive female faces (Maner et al., 2003; Becker et
al., 2005). Inter-sex biases in men were interpreted as reflecting sensitivity to
potential mates, while intra-sex biases in women were interpreted as serving to catalog
quality competitors. Although these studies point toward functionally specialized
cognitive modules, Fitzgerald et al. (2016) argue a focus on facial attractiveness
is limited, since it is not the sole arbiter of mating decisions. Other potentially
useful features include clothing, body shape, and social information (Buss, 1989).
Moreover, physical characteristics of potential mates are only one component of the
representation that is formed during an encounter. In addition to the appearance of
who was there, people will need to remember that something occurred (what) at a particular
time (when) in a particular place (where) (Nairne, 2015).
Before Fitzgerald et al. (2016) few papers showed a correspondence between mate-choice
relevant cues and memory enhancements for related stimulus (for exceptions, see Allan
et al., 2012; Smith et al., 2012, 2013). Those that had done so exclusively identified
effects in women, even in instances where data was gathered for men. Women's recall
was consistently better for incidental details associated with men boasting features
congruent to their mating strategies vs. less desirable competitors, i.e., masculine
features for short-term preferences, and feminine features for long term (Gangestad
and Simpson, 2000; Fink and Penton-Voak, 2002). In these studies, it was hypothesized
that the greater cost of unsuccessful courtship facing women would have necessitated
the need to more easily retrieve memories, from a variety of past contexts, into the
personality and behavior of men.
To my knowledge, Fitzgerald et al. (2016) were first to discover biases in men's memory,
for concurrent information, prompted by cues of mate quality in women. Crucially the
task demands diverged from previous paradigms. Across two studies they showed men
variants on the same image of a woman in black, with an accompanying paragraph of
biographical information. This included her name, college major, job, and places she
would like to visit, among other things. Next, participants' memory for details about
the target and their appearance was assessed as a function of her waist to hip ratios
(WHR). This cue was selected (a) to counter the limited focus on facial/vocal displays
and (b) its apparent role in health, fecundity, and cognitive ability (Singh, 1993).
Digital manipulations were used to give her a measurement between 0.50 and 0.90. In
both free recall and recognition conditions, participants who viewed the model with
a WHR of 0.50 or 0.90 recalled and recognized fewer personal details than those who
saw her with a WHR of 0.60, 0.70, or 0.80. Memory data was complemented by preference
data in which women with a WHR of 0.70 received the highest ratings. Elsewhere men
have identified this measurement as particularly attractive (Singh, 2002; Dixson et
al., 2011).
The authors theorize that their data differs from previous findings because they tested
memory for information explicitly linked to a target, instead of it being incidental.
Parental investment theory (Trivers, 1972) stipulates that asymmetric courtship costs
mean men's optimal mating strategies emphasize quantity vs. quality (Kenrick et al.,
1990; Buss and Schmitt, 1993). That is to say, men are expected to devote a larger
proportion of their mating effort toward short vs. long term relationships. Thus,
Fitzgerald et al. (2016) anticipate that a functional memory system in men should
be oriented toward information useful for determining a prospect's mating value. Cited
candidates include physical features, biographical data, values, and demographic background.
A memory system dedicated toward retaining these features may heighten fitness-relevant
decisions by helping men to identify suitable partners.
In contrast, Smith et al. (2012) propose a functional system for women should aid
comparative vs. absolute evaluation (Bateson and Healy, 2005). It should therefore
be geared toward indexing men's behavior over time instead of first impressions. Female
participants' memory biases were for subsidiary details, implying a generalized effect
following increased arousal/attention, during episodes when a preferred male was present.
This information potentially helps them assess mates against (a) assumptions of their
behavior, as signaled morphologically (Perrett et al., 1998), and (b) absent competitors.
In instances when men defy expectations, women potentially forfeit good genes, or
get misled by a mate signaling an investment they do not later meet. Both outcomes
are maladaptive. Hence memory should prioritize what desirable men say or do vs. who
they are per se (Allan et al., 2012; Smith et al., 2013). Data from Horgan et al.
(2015) suggests this pattern is true to the extent that women are long term oriented.
Research into sex-specific memory biases for mate-choice relevant stimulus is still
in its infancy. Yet it is encouraging to see evidence for the impact of delineated
selection pressures between men and women. The data from Fitzgerald et al. (2016)
is significant because it addresses a discrepancy in the adaptive memory literature.
It further extends social perception research, surrounding men's mating strategies,
into the cognitive domain, building on the functionalist framework proposing a sociosexual
role of memory. In doing so the authors also bring us closer to answering Baddeley's
question.
Author contributions
The author confirms being the sole contributor of this work and approved it for publication.
Conflict of interest statement
The author declares that the research was conducted in the absence of any commercial
or financial relationships that could be construed as a potential conflict of interest.