Night Owls Research Articles

Circadian rhythms and mood disorders: a guide for the perplexed.

Circadian rhythms and mood disorders: a guide for the perplexed.

The Impact of Early Bedtimes on Adolescent Caloric Intake Varies by Chronotype

PurposeAdolescent sleep restriction is common and can lead to overeating. Here, we test whether lengthening sleep via early bedtimes affects dietary intake differently for adolescents accustomed to a later sleep phase (“night owls”) versus an earlier sleep phase (“morning larks”). MethodsUsing a randomized cross-over design, 67 adolescents changed bedtimes to create five-night periods of sleep restriction (6.5 hours in bed) versus healthy sleep (10 hours in bed). Caloric intake was measured via validated interviews. Phase preference was based on participants' premanipulation sleep. ResultsActigraphy verified that the manipulation altered sleep regardless of phase preference. Phase preference moderated the effect of the manipulation on cumulative caloric intake (p = .01–.03). Night owls showed little effect, but morning larks reduced their evening intake during healthy sleep. ConclusionsAn “early to bed” approach confers little dietary benefit for night owls but may have a protective effect for adolescents who gravitate toward earlier bedtimes.

Morningness–eveningness and performance-based emotional intelligence

The aim of the present article is to determine whether recently shown positive relationships between self-reported emotional intelligence (EI) and morningess preference exist when EI is measured with an ability-based test. In two studies (study 1: N = 206 and study 2: N = 184), we applied two different morningness–eveningness questionnaires and a performance test of EI consisting of four dimensions (perception, understanding, assimilation, managing). The two studies provided similar results indicating that “night owls” have higher EI than “larks”; specifically, evening-oriented subjects showed greater ability in emotion perception and understanding, as compared to morning-oriented individuals. The obtained results were in line with hitherto existing research on chronotype and general intelligence. The results provide further evidence for a cognitive character of ability-based EI and accentuate its different nature when compared to self-reported EI. The main findings are discussed in terms of evolutionary theories of circadian preferences, EI and mental abilities.

Association between delayed bedtime and sleep-related problems among community-dwelling 2-year-old children in Japan.

BackgroundAlthough delayed sleep timing causes many socio-psycho-biological problems such as sleep loss, excessive daytime sleepiness, obesity, and impaired daytime neurocognitive performance in adults, there are insufficient data showing the clinical significance of a ‘night owl lifestyle’ in early life. This study examined the association between habitual delayed bedtime and sleep-related problems among community-dwelling 2-year-old children in Japan.MethodsParents/caregivers of 708 community-dwelling 2-year-old children in Nishitokyo City, Tokyo, participated in the study. The participants answered a questionnaire to evaluate their child’s sleep habits and sleep-related problems for the past 1 month.ResultsOf the 425 children for whom complete data were collected, 90 (21.2%) went to bed at 22:00 or later. Children with delayed bedtime showed significantly more irregular bedtime, delayed wake time, shorter total sleep time, and difficulty in initiating and terminating sleep. Although this relationship indicated the presence of sleep debt in children with delayed bedtime, sleep onset latency did not differ between children with earlier bedtime and those with delayed bedtime. Rather, delayed bedtime was significantly associated with bedtime resistance and problems in the morning even when adjusting for nighttime and daytime sleep time.ConclusionsEven in 2-year-old children, delayed bedtime was associated with various sleep-related problems. The causal factors may include diminished homeostatic sleep drive due to prolonged daytime nap as well as diurnal preference (morning or night type) regulated by the biological clock.

Seasonal variation in affective and other clinical symptoms among high-risk families for bipolar disorders in an Arctic population

BackgroundIn bipolar disorder (BD), seasonality of symptoms is common and disturbances in circadian rhythms have been reported.ObjectivesWe identified high-penetrance families in a geographically restricted area in Northern Fennoscandia and studied the seasonal variation of clinical symptoms among BD subjects and their healthy relatives.DesignWe explored the clinical characteristics of subjects living in Northern Fennoscandia, with extreme annual variation in daylight. Among known indigenous high-risk families for BD, we compared the affected ones (N=16) with their healthy relatives (N=15), and also included 18 healthy non-related controls from the same geographical area. Seasonal fluctuation in clinical measures was followed up at the 4 most demarcated photoperiodic time points of the annual cycle: around the summer solstice and autumn equinox in 2013, the winter solstice in 2013/2014, and the spring equinox in 2014. In the baseline, lifetime manic symptoms [Mood Disorder Questionnaire (MDQ)] and morningness–eveningness questionnaire type (MEQ) were registered, whereas in the follow-up, depressive [Beck Depression Inventory (BDI)] and distress [General Health Questionnaire (GHQ-12)] symptoms and alcohol consumption and sleep were recorded.ResultsPossibly indicative or statistically significant differences in symptoms between the affected subjects and their healthy relatives were the BDI winter (13.3 vs. 2.6, t=−2.51, p=0.022) and spring scores (12.6 vs. 3.2, t=−1.97, p=0.063) and GHQ winter (4.2 vs. 0.82, t=−2.08, p=0.052) and spring scores (3.8 vs. 0.82, t=−1.97, p=0.063). Scores were higher among the affected subjects, exceeding a possibly diagnostic threshold (10 and 3) at all the time points, and without the notable seasonality which was observed among the healthy relatives. In the overall population, MDQ and MEQ scores had an inverse correlation (−0.384, significant at 0.016), indicating increased lifetime manic behaviour among “the night owl” chronotype subjects.ConclusionsIn an Arctic population sample, we found different seasonal fluctuation in mood and distress symptoms and sleep duration scores between subjects with bipolar spectrum disorders and their healthy relatives. Despite the relatively small sample size, the results indicate that the symptoms and signs of BD relate to a disturbance in seasonal variation. Seasonal variation can be considered as an interesting endophenotype for BD and a promising target for further genetic studies.

Two Poems

40 WLT NOVEMBER / DECEMBER 2015 Two Poems by Hedy Habra How Much of Yourself Remains Within the Walls of a Home? after Jeremy Miranda’s Salt Marsh (2014) I wanted to dive into the troubled waters of forgotten memories, haunt the house of early emotions but found it empty. I wanted to find the lingering scent of jasmine where jasmine never grew, even if it wasn’t spring. Unspoken words fall heavily on the kitchen tiles: a cascade of rough-edged syllables flood the floor. My chair is glued to the table, I’m trapped within clouds preventing me from seeing how the marsh grows wider, how walls collapse, spikes and bluish-green leaves crested with plumes line the edge of the water where glasswort blushes against sea lavender. I’d run my fingers over the red round stems, crush the purple petals under my teeth to release its essential oils. I can still see the russet tree’s wavering reflections, its roots, that seemed to come down from the sky. Your body awakens each night under my fingertips, shortening the distance between my lips and your skin, until your body remembers, until the sky sinks into water, mist so thick, a hummingbird floats in minute droplets in suspension. I feel the current of the first kiss in my curls, our knees shaking. Jeremy Miranda, Salt Marsh, 2014, acrylic on panel. Courtesy of the artist. cover feature art poetry WORLDLITERATURETODAY.ORG 41© 2015 artists rights society ( ARS ), new york / vegap , madrid photo credit : gianni dagli orti / the art archive at art resource , ny left Remedios Varo, Creation of the Birds (La creación de las aves), 1957, oil on masonite, © by the artist, dacs/vegap. For a biographical sketch of Remedios Varo, turn to page 39. Hedy Habra (HedyHabra.com) is the author of two poetry collections, Tea in Heliopolis (2013), winner of the USA Best Book Award and finalist for the International Poetry Book Award, and Under Brushstrokes (2015), inspired by visual art. Recipient of the Nazim Hikmet Poetry Award, she is also the author of a story collection, Flying Carpets (2013), winner of the Arab American National Book Award’s Honorable Mention. Jeremy Miranda is a contemporary artist, born in Newport, Rhode Island. He creates complex environments that are a hybridization of both interior and exterior spaces. He is interested in the landscape and how people control, fetishize, and dwell within it. A Bird’s Song, Unraveled after Remedios Varo’s Creation of the Birds (1957) All artists are night owls, she thinks, as circles grow wider around her eyes. Eyelids lowered, her brush, an extension of her violin-shaped heart, adds the last touches of blush to the feathers’ tips. She tries to remember the right words thrown pell-mell in the folds of memory . . . memory adds layers to meaning . . . wants to retrieve numbers and signs from slumber, relive the initial moment, imagines how wingless molecules rub against each other in the copper alembic. All it takes is a double binding broken loose to find the right combination: Only verbs are allowed. Aren’t they the heart of a sentence? What of a wordless message as those from the heart strung from the right chord? She holds iridium glasses to gather light from stardust . . . hoopoes, hummingbirds, kingfishers, finches, sparrows, swallows, warblers, orioles . . . she has lost track of how many species flew in search of an answer, each bird carrying its own song, from all corners of the earth. Her wings aren’t strong enough to cross the seven valleys. She needs to send an emissary to partake in the colloquy of birds. Barefoot, she steps over shades of silver dust strewn by shooting stars, conjures up their broken light night after night. The original formula . . . lost since time immemorial . . . led to confusing myths such as people drowning in their own reflection or making love to their own creation. She knows the secret of the bird’s song, its loops and roundness, but chooses silence, lets its wings flutter through the open window. She will try again. ...

Night Owls–The “B” People

Night Owls–The “B” People

The slow and fast life histories of early birds and night owls: their future- or present-orientation accounts for their sexually monogamous or promiscuous tendencies

In this study we tested the hypothesis that inter-individual variation in morningness–eveningness (i.e., chronotype) is associated with variation in a composite measure of life history (the mini-K) such that morning-types (i.e., early birds) exhibit traits typically associated with slow life histories while evening-types (i.e., night owls) exhibit traits typically associated with fast life histories. In addition, we tested the hypothesis that time perspective may be one of the psychological mechanisms mediating the relationship between chronotype and socio-sexuality. Study participants were 95 heterosexual young men, most of whom were university students. Chronotype, life-history traits, socio-sexuality, and time perspective were assessed with well-established self-report measures. Variations in chronotype and in life-history traits were significantly associated in the direction predicted by our hypothesis. Consistent with our second hypothesis, time perspective emerged as a significant mediator of the association between chronotype and socio-sexuality so that the future orientation of morning-types was associated with their long-term mating orientation and relatively low sexual experience, while the present orientation of evening-types was associated with their short-term mating orientation and greater sexual experience. Our study provides the first evidence that variation in chronotype may be adaptive and elucidates one of the psychological mechanisms underlying the life history and reproductive strategies of male early birds and night owls.

Morningness–eveningness and intelligence among high-achieving US students: Night owls have higher GMAT scores than early morning types in a top-ranked MBA program

Individuals with a propensity to wake up early in the morning (“early-morning” types) and those who like to stay up late at night (“night owls”) often exhibit distinctive psychological and physiological profiles. Previous research has shown that night owls score higher than early-morning people on different measures of cognitive ability and academic achievement. Baseline cortisol is one of the physiological variables associated with variation in chronotype and cognitive function. In this study we investigated whether a relationship between chronotype and performance is present also in the high range of intellectual ability and academic achievement, namely, among graduate students in a top-ranked MBA program in the US. In addition, we measured baseline cortisol levels in saliva samples collected in the early afternoon and analyzed them in relation to chronotype and GMAT scores. As predicted, GMAT scores were significantly higher among night owls than among early-morning types, regardless of sex. GMAT scores were also significantly higher among men than women, regardless of chronotype. Morningness/eveningness was not significantly associated with variation in sleep amount or in undergraduate or graduate GPA scores, suggesting that the association between eveningness and high GMAT scores was not due to differences in study effort or skills. Sex, chronotype and baseline cortisol jointly accounted for 14% of the total variance in GMAT scores; baseline cortisol, however, did not mediate the effect of chronotype on GMAT scores. Consistent with the results of previous research, our study shows that the effects of chronotype on cognitive ability and academic performance are relatively small but detectable even among high-achieving individuals. The mechanism linking eveningness and high cognitive function remains unclear but the role of personality traits and neuroendocrine function warrants further investigation.

Night Owl Women are Similar to Men in Their Relationship Orientation, Risk-taking Propensities, and Cortisol Levels: Implications for the Adaptive Significance and Evolution of Eveningness

Individual differences in morningness/eveningness are relatively stable over time and, in part, genetically based. The night-owl pattern is more prevalent in men than in women, particularly after puberty and before women reach menopause. It has been suggested that eveningness evolved relatively recently in human evolutionary history and that this trait may be advantageous to individuals pursuing short-term mating strategies. Consistent with this hypothesis, eveningness is associated with extraversion, novelty-seeking, and in males, with a higher number of sexual partners. In this study, I investigated whether eveningness is associated with short-term relationship orientation, higher risk-taking, and higher testosterone or cortisol. Both female and male night-owls were more likely to be single than in long-term relationships than early morning individuals. Eveningness was associated with higher risk-taking in women but not in men; this association was not testosterone-dependent but mediated by cortisol. Female night-owls had average cortisol profiles and risk-taking tendencies more similar to those of males than to those of early-morning females. Taken together, these findings provide some support to the hypothesis that eveningness is associated with psychological and behavioral traits that are instrumental in short-term mating strategies, with the evidence being stronger for women than for men.

Circadian polymorphisms in night owls, in bipolars, and in non-24-hour sleep cycles.

People called night owls habitually have late bedtimes and late times of arising, sometimes suffering a heritable circadian disturbance called delayed sleep phase syndrome (DSPS). Those with DSPS, those with more severe progressively-late non-24-hour sleep-wake cycles, and those with bipolar disorder may share genetic tendencies for slowed or delayed circadian cycles. We searched for polymorphisms associated with DSPS in a case-control study of DSPS research participants and a separate study of Sleep Center patients undergoing polysomnography. In 45 participants, we resequenced portions of 15 circadian genes to identify unknown polymorphisms that might be associated with DSPS, non-24-hour rhythms, or bipolar comorbidities. We then genotyped single nucleotide polymorphisms (SNPs) in both larger samples, using Illumina Golden Gate assays. Associations of SNPs with the DSPS phenotype and with the morningness-eveningness parametric phenotype were computed for both samples, then combined for meta-analyses. Delayed sleep and "eveningness" were inversely associated with loci in circadian genes NFIL3 (rs2482705) and RORC (rs3828057). A group of haplotypes overlapping BHLHE40 was associated with non-24-hour sleep-wake cycles, and less robustly, with delayed sleep and bipolar disorder (e.g., rs34883305, rs34870629, rs74439275, and rs3750275 were associated with n=37, p=4.58E-09, Bonferroni p=2.95E-06). Bright light and melatonin can palliate circadian disorders, and genetics may clarify the underlying circadian photoperiodic mechanisms. After further replication and identification of the causal polymorphisms, these findings may point to future treatments for DSPS, non-24-hour rhythms, and possibly bipolar disorder or depression.

Let’s Go to Morocco, and Trains

Let’s Go to Morocco, and Trains Anzhelina Polonskaya (bio) —translated from the Russian by Andrew Wachtel Let’s Go to Morocco Let’s go to Morocco.Maybe things are different there:mountains and seas, other streets.Lions don’t fall into traps,and hares don’t whine like babies.And people don’t have scars from collarbone to shoulder.An old lady will come up to us: “let me tell your fortune?”“Predict your future luck.”Sorry, I don’t know those terms.Better take this coin and buy yourselfa bright scarf and some loose pants.And we will go, sail away, leave.But still, Morocco will never end.Under a deep blue sky we’ll become like an almond branch.This will extend your life, and mine as well; at least for a time. 2013 [End Page 312] Trains It’s good there are trains.With conductors in fraying jacketsand worn heels.Green and raspberry streamers.You can go away somewhere on them,my friend, somewhere.To avoid thinking about an empty glass or a plowed field.On your bunk you can turn your back on everyone.The lady selling potatoes at the rainy station,the priest peddling eternal life.Or, if you have no ticket,you can breathe in the piney smell of the ties,without leaving the bedsof hortensia and white lilies.Lying in your bed, you can hear the train whistle,and the night owl moaningof the oil-filled tank cars.And you really could go somewhere. 2013 [End Page 313] Anzhelina Polonskaya Anzhelina Polonskaya was born in a small town near Moscow, where she is currently preparing a new volume of poetry for publication. She is a member of the Moscow Union of Writers and the Russian PEN center. Her book, A Voice, appeared in Northwestern University Press’s “Writings from an Unbound Europe,” and was shortlisted for the 2005 Corneliu M. Popescu Prize for European Poetry in Translation. Polonskaya’s work has appeared in many journals, including American Poetry Review, International Poetry Review, Massachusetts Review, and Prairie Schooner. She is also the recipient of a Rockefeller Fellowship. Andrew Wachtel Andrew Wachtel is the president of the American University of Central Asia in Bishkek, Kyrgyzstan. Previously he was dean of the Graduate School and director of the Roberta Buffett Center for International and Comparative Studies at Northwestern University; he is also a fellow of the American Academy of Arts and Sciences and a member of the Council on Foreign Relations. Wachtel’s interests range from Russian literature and culture to East European and Balkan culture, history, and politics to contemporary Central Asia. His most recent books are The Balkans in World History (Oxford University Press, 2008) and Russian Literature (with Ilya Vinitsky, Polity Press, 2008). He has translated poetry and prose from Russian, Bosnian/Croatian/Serbian, Bulgarian, and Slovenian, and is currently working on a cultural nationalism project in Central Asia, particularly Kyrgyzstan. Copyright © 2014 Middlebury College Publications

Chronotype distribution in bipolar disorder and major depressive disorder in an in-patient sample at a tertiary care center

Introduction Circadian rhythm disturbances have been implicated in the etiopathogenesis of mood disorders. Chronotype is indicative of one’s innate circadian preference, and correlates with physiological measures of circadian phase. A Korean study found a preponderance of “night owls” among clinically stable bipolar outpatients and other investigations have shown phase advances among various physiologic parameters in patients with major depressive disorder (MDD). This study examined chronotype distribution among inpatients with bipolar disorder and MDD. We hypothesized a preponderance of “night owls” among bipolar patients and “early birds” among MDD patients. Materials and methods Adult inpatients with well-established diagnoses of bipolar disorder (type I, II and NOS) and MDD were identified and recruited over a period of 2 years. Patients with cognitive impairment, disorganized thinking, and affective instability impairing questionnaire completion were excluded as were those 58 correlate with morningness (early bird), and Results Out of 98 MDD, 98 bipolar patients and 59 controls, there were 59(60%), 61 (62%) and 47(80%) females [ p = 0.03], with median (IQR) age of 45(33–53), 44 (34–52) and 31(26–44) [ p p = 0.19]. After adjusting for age and gender, the chronotypes continued to have no association with diagnosis [ p = 0.49]. Conclusion Since there were no differences in baseline chronotypes among inpatients with mood disorders and controls, subjective chronotypes do not serve as reliable markers to differentiate bipolar disorder and MDD. Contrasting results from previous studies warrant clarification with further investigations. Objective circadian assessments such as the timing of the core body temperature minimum and the dim light melatonin onset should also be studied for correlations. Acknowledgements Dr. Simon Kung, MD.

Internal time: chronotypes, social jet lag, and why you're so tired

Early birds and night owls are born, not made. Sleep patterns may be the most obvious manifestation of the highly individualized biological clocks we inherit, but these clocks also regulate bodily functions from digestion to hormone levels to cognition. Living at odds with our internal timepieces, Till Roenneberg shows, can make us chronically sleep deprived and more likely to smoke, gain weight, feel depressed, fall ill, and fail geometry. By understanding and respecting our internal time, we can live better. Internal Time combines storytelling with accessible science tutorials to explain how our internal clocks work - for example, why morning classes are so unpopular and why lazy adolescents are wise to avoid them. We learn why the constant twilight of our largely indoor lives makes us dependent on alarm clocks and tired, and why social demands and work schedules lead to a social jet lag that compromises our daily functioning. Many of the factors that make us early or late chronotypes are beyond our control, but that doesn't make us powerless. Roenneberg recommends that the best way to sync our internal time with our external environment and feel better is to get more sunlight. Such simple steps as cycling to work and eating breakfast outside may be the tickets to a good night's sleep, better overall health, and less grouchiness in the morning.

Identification of individual Eastern Screech-Owls Megascops asio via vocalization analysis

To more easily and non-invasively monitor urban Eastern Screech-Owl populations, we developed a method of distinguishing individual owls using their calls. A set of seven variables derived from recordings of ‘bounce’ calls taken from 10 known (either free-ranging birds recorded at a single site on a single night or identifiable captive owls) owls was tested using a model-based clustering analysis (Mclust) as a method of discriminating individual owls. The cluster analysis correctly classified these calls with 98% accuracy. A second set of calls from nine owls was used to further test the method and correctly classified 84% of the calls using the same variables. Four owls were recorded repeatedly from 2008 to 2010 to determine the extent to which calls changed over time; the cluster analysis correctly assigned 89% of the calls to the correct owl regardless of the year the recordings were made. Based on these results, we are confident that the Mclust analysis can be used to reliably and safely estimate abundance and survival of Eastern Screech-Owls within the time frame of a few years and of population sizes < 15 owls.

Susceptibility and lack of evidence for a viremic state of rabies in the night owl monkey, Aotus nancymaae.

BackgroundRabies causes an acute fatal encephalomyelitis in most mammals following infection with rhabdovirus of the genus Lyssavirus. Little is known about rabies virus infection in species of New World non-human Primates (NHP). To investigate the suitability of the owl monkey Aotus nancymaae asissue sections examined were unremarkable for inflammation or other histologic signs of rabies a viable animal model for rabies virus candidate vaccine testing, we used clinical presentation, serology, viral isolation, and PCR to evaluate the incubation period, immunity, and pathogenesis of infected animals. We tested the hypothesis that no viremic state exists for rabies virus.MethodsEight monkeys divided into two equal groups were inoculated intramuscularly either in the neck or footpad with 105 pfu of rabies virus (Pasteur/V-13R) and observed for >130 days. Oral and blood samples were collected and analyzed.ResultsTwo monkeys inoculated in the neck displayed classic paralytic rabies. The mean incubation period was 11.5 days. The average maximum IgG response (antibody titer >0.200 O.D.) was achieved at day 10.0 and 62.3 in the clinical rabies and non-clinical rabies cases, respectively (p = 0.0429). No difference in IgM or IgG time to seroconversion or average maximum IgM level was observed between neck versus footpad inoculation groups. No viremia or viral shedding was detected by PCR or viral isolation during the observation period, including within the two symptomatic animals three days after disease onset. Tissue sections examined were unremarkable for inflammation or other histologic signs of rabies within the asymptomatic animal. Similarly none of the brain sections exhibited immunoreactivity for rabies virus antibody.DiscussionThis study demonstrates there is no difference in time to immune response between inoculation sites and distance to the brain; however, immune response tends to be more rapid in cases of clinically apparent disease and prolonged in cases infected at sites further from the brain.ConclusionsOur findings support the hypothesis that a viremic state for rabies does not exist in the New World Monkey, Aotus nancymaae, and it appears that this species may be refractory to infection. The species does provide a suitable model to assess post infection immune responses. Additional studies that address the limitations of sample size, length of observation, and lack of measurable infection should be conducted.

Effects of diurnal variation on the Test of Variables of Attention performance in young adults with attention-deficit/hyperactivity disorder.

The Test of Variables of Attention (TOVA) is a continuous performance test that assesses attention, impulsivity, and processing speed. Continuous performance tests are used in the assessment of attention-deficit/hyperactivity disorder (ADHD) in children and adults. TOVA norms are based on a morning administration, and any TOVA administered after 1:00 p.m. is flagged as potentially invalid. Whereas the testing time recommendations make sense for pediatric samples, it is unclear whether they are appropriate for young adults, who typically show significant phase delay in their diurnal rhythms. The current study explores the impact of time of day on TOVA performance in young adults with ADHD. Participants were randomly assigned to either morning or afternoon administration. We found no significant diurnal variation in TOVA performance. We also found no interaction between diurnal preference and time of day of administration. Night owls endorsed more inattention symptoms on a self-report measure than more intermediate individuals but actually made significantly fewer omission (inattention) errors on the TOVA. Self-reported symptoms of inattention showed moderate, significant correlations with various TOVA performance indices. Self-reported symptoms of hyperactivity and impulsivity, however, showed no relationship to TOVA performance. These results suggest that the TOVA can be administered to adults with ADHD outside of the hours recommended in the manual without significantly compromising the interpretative validity of test score interpretation. Thus, a TOVA report that is consistent with ADHD should not be dismissed simply because it was administered in the late afternoon.

Review

164 Michigan Historical Review professional life. Lehto covers Houghton‘s life chronologically in twenty chapters, carefully detailing the remarkable amount of travel, lectures, research, and public service that Houghton accomplished in only fifteen years after he arrived in Detroit in 1830. Lehto argues that the Copper Country did not fully define Houghton‘s life, although his attempt to push the focus of his book away from the Keweenaw is hindered by the lack of personal details about his subject. Stronger editing might have remedied the book‘s shortcomings. The endnotes are not numbered; nor do they follow a consistent format. Readers would also have benefited from an index. Lehto repeatedly uses vague unsourced references to ―historians‖ or statements that ―historians have observed,‖ and he employs the term ―revisionist‖ (with a strong negative connotation) when he takes ―some revisionist historians‖ (p. 134) to task, while ignoring his own ―revisionist‖ efforts to reshape our perceptions of Houghton‘s life. Lehto‘s efforts to track down various scattered Houghton sources also lead him to occasional digressions, including a complaint about research fees to view a painting (p. 134). A more important criticism is that Lehto‘s narrow focus on the particulars of Houghton‘s life and his legacy omits the broader context that the best popular biographies provide. The narrative touches on Houghton‘s legacy but does not place him among other explorers of the era, such as Stephen H. Long and John C. Fremont. Douglass Houghton‘s voyages may not have left a lasting impression, but they were very much a part of the spirit of his time. Despite these limitations, however, Lehto‘s work is a wellresearched , highly readable, interesting work on a major figure in Michigan‘s early history, and it should reach a broad readership. Matthew Lawrence Daley Grand Valley State University Patrick Livingston. Summer Dreams: The Story of Bob-Lo Island. Detroit: Wayne State University Press, 2008. Pp. 192. Illustrations. Index. Note on sources. Notes. Paper, $24.95. Patrick Livingston‘s Summer Dreams is a cradle-to-grave history of Bob-Lo Island, the Detroit-area amusement park that closed in 1993 after nearly a century of operation. Although its amusements always were American-owned, the island itself is a narrow dot of Canadian Book Reviews 165 territory eighteen miles south of the city where the Detroit River opens into Lake Erie. Throughout its history, Bob-Lo was a remote destination accessible only by ferry or steamship. That remoteness was not unusual for an amusement park in 1900, but Bob-Lo survived even as Detroit and the rest of the continent chose the convenience of travel by automobile. Each summer members of the region‘s middle class, by the hundreds of thousands, temporarily abandoned their cars to get away to ―the greatest spot on earth in their own backyard‖ (p. 3). Livingston‘s studiously researched history presents accounts of a fondly remembered local resort and of the ―people who brought the amusement park to life‖ (p. 3). Generously illustrated and thoughtfully conceived, Summer Dreams further explores the history of this region by examining its popular summertime playground. Opened in the late 1890s during the first era of American amusement parks, Bob-Lo Island did not copy its more famous contemporaries at New York‘s Coney Island. Those resorts lured urban hordes with mechanical thrills, exotic illusions, and brilliant electric lighting. For generations, the owners of Bob-Lo sought to attract ―the more desirable element of pleasure seekers‖ (p. 47) with an alternative vision of escape to a quietly illuminated, wooded ―isle of picnic and pleasure‖ (p. 39). Modern dance steps that appeared lewd were banned at Bob-Lo; beer consumption was prohibited until 1937, and then allowed only on ferries. Aside from a carousel, mechanical rides were kept to a minimum until 1957, when the island was converted into a modern amusement park. Even then, Bob-Lo‘s owners still targeted a mass customer base, composed not of thrill seekers and night owls, but of respectable middle-class families. In Livingston‘s interviews, these people describe their deeply felt memories of a place cherished for its tranquility and separation ―from the everyday life‖ (p. 101). However, Livingston also...

Evolutionary psychology and intelligence research.

This article seeks to unify two subfields of psychology that have hitherto stood separately: evolutionary psychology and intelligence research/differential psychology. I suggest that general intelligence may simultaneously be an evolved adaptation and an individual-difference variable. Tooby and Cosmides's (1990a) notion of random quantitative variation on a monomorphic design allows us to incorporate heritable individual differences in evolved adaptations. The Savanna-IQ Interaction Hypothesis, which is one consequence of the integration of evolutionary psychology and intelligence research, can potentially explain why less intelligent individuals enjoy TV more, why liberals are more intelligent than conservatives, and why night owls are more intelligent than morning larks, among many other findings. The general approach proposed here will allow us to integrate evolutionary psychology with any other aspect of differential psychology.

Why night owls are more intelligent

The origin of values and preferences is an unresolved theoretical problem in social and behavioral sciences. The Savanna–IQ Interaction Hypothesis suggests that more intelligent individuals are more likely to acquire and espouse evolutionarily novel values and preferences than less intelligent individuals, but general intelligence has no effect on the acquisition and espousal of evolutionarily familiar values and preferences. Individuals can often choose their values and preferences even in the face of genetic predisposition. One example of such choice within genetic constraint is circadian rhythms. Survey of ethnographies of traditional societies suggests that nocturnal activities were probably rare in the ancestral environment, so the Hypothesis would predict that more intelligent individuals are more likely to be nocturnal than less intelligent individuals. The analysis of the National Longitudinal Study of Adolescent Health (Add Health) confirms the prediction.