{{short description|State of active attention by high sensory awareness such as being watchful}} {{Mindfulness|Similar concepts}} '''Alertness''' is a state of active attention characterized by high sensory awareness. Someone who is alert is vigilant and promptly meets danger or emergency, or is quick to perceive and act. Alertness is a psychological and physiological state.
Lack of alertness is a symptom of a number of conditions, including narcolepsy, attention deficit hyperactivity disorder, chronic fatigue syndrome, depression, Addison's disease, and sleep deprivation. Pronounced lack of alertness is an altered level of consciousness. States with low levels of alertness include drowsiness.
The word is formed from "alert", which comes from the Italian {{lang|it|all'erta}} (on the watch, literally: on the height; 1618).{{cn|date=July 2023}}
Wakefulness refers mainly to differences between the sleep and waking states; vigilance refers to sustained alertness and concentration. Both terms are sometimes used synonymously with alertness.
==Importance and difficulty== [[File:Allegory of Vigilance by Domenico Tintoretto.jpg|thumb|Domenico Tintoretto, ''Allegory of Vigilance'']]
People who have to be alert during their jobs, such as air traffic controllers or pilots, often face challenges maintaining their alertness. Research shows that for people "...engaged in attention-intensive and monotonous tasks, retaining a constant level of alertness is rare if not impossible." If people employed in safety-related or transportation jobs have lapses in alertness, this "may lead to severe consequences in occupations ranging from air traffic control to monitoring of nuclear power plants."<ref>{{Cite web |title=Alertness Monitoring |url=http://cnl.salk.edu/~jung/alert.html|archive-url=https://web.archive.org/web/20220930155558/http://cnl.salk.edu/~jung/alert.html|archive-date=2022-09-30|website=The Salk Institute|date=17 November 1995|last=Jung|first=Tzyy-Ping}}</ref>
==Neurobiological pathways== {{See also|Stimulant#Mechanisms of action|Neuroenhancement}} Neurotransmitters that can initiate, promote, or enhance wakefulness or alertness include serotonin, (nor)epinephrine, dopamine (e.g. blockade of dopamine reuptake), glutamate, histamine, and acetylcholine. Neuromodulators that can do so include the neuropeptide orexin. Similarly inhibition or reduction of mechanisms causing sleepiness, or drowsiness such as certain cytokines and adenosine (as with caffeine) may also increase perceived wakefulness and thus alertness.{{ambiguous|reason=sentence structure makes it unclear whether cytokines and/or adenosine are the things that inhibit or reduce alertness-inhibiting mechanisms, or are alertness-inhibiting mechanisms|date=July 2023}}<ref name="10.3920/BM2021.0122">{{cite journal |last1=Haarhuis |first1=J.E. |last2=Kardinaal |first2=A. |last3=Kortman |first3=G.A.M. |title=Probiotics, prebiotics and postbiotics for better sleep quality: a narrative review |journal=Beneficial Microbes |date=3 August 2022 |volume=13 |issue=3 |pages=169–182 |doi=10.3920/BM2021.0122 |pmid=35815493 |s2cid=250423761 |url=https://www.researchgate.net/publication/361911954|doi-access=free }}</ref><ref name="10.1016/j.metabol.2006.07.007">{{cite journal |last1=Miller |first1=Diane B. |last2=O'Callaghan |first2=James P. |title=The pharmacology of wakefulness |journal=Metabolism |date=October 2006 |volume=55 |issue=10 Suppl 2 |pages=S13–S19|doi=10.1016/j.metabol.2006.07.007 |pmid=16979420 }}</ref><ref>{{cite journal |last1=Sakurai |first1=Takeshi |title=Roles of orexin/hypocretin in regulation of sleep/wakefulness and energy homeostasis |journal=Sleep Medicine Reviews |date=August 2005 |volume=9 |issue=4 |pages=231–241 |doi=10.1016/j.smrv.2004.07.007|pmid=15961331 }}</ref>
Wakefulness depends on the coordinated effort of multiple brain areas. These are affected by neurotransmitters and other factors.<ref name="10.1016/j.metabol.2006.07.007"/> Many Neurotransmitters are in effect to experience wakefulness to include GABA, Acetylcholine, Adenosine, Serotonin, Norepinephrine, Histamine, and Dopamine.<ref name=":0">{{Cite journal |last1=Watson |first1=Christopher J. |last2=Baghdoyan |first2=Helen A. |last3=Lydic |first3=Ralph |date=December 2010 |title=Neuropharmacology of Sleep and Wakefulness |journal=Sleep Medicine Clinics |volume=5 |issue=4 |pages=513–528 |doi=10.1016/j.jsmc.2010.08.003 |issn=1556-4088 |pmc=3026477 |pmid=21278831}}</ref> There is not an isolated neurotransmitter that alone is responsible for the sensation of wakefulness. However, it is known that many transmitters are used together to cause this effect.<ref name=":0" /><ref name=":1" /> Research to map the wakefulness circuitry is ongoing.<ref name=":1">{{cite journal |last1=Grady |first1=Fillan S. |last2=Boes |first2=Aaron D. |last3=Geerling |first3=Joel C. |title=A Century Searching for the Neurons Necessary for Wakefulness |journal=Frontiers in Neuroscience |date=2022 |volume=16 |article-number=930514 |doi=10.3389/fnins.2022.930514 |pmid=35928009 |pmc=9344068 |issn=1662-4548|doi-access=free }}</ref>
Beta power has been used as an indicator of cortical arousal or alertness by several studies.{{elucidate|reason=what is beta "power"? what about it indicates alertness? how was it chosen as a proxy for alertness, and why is it considered reliable?|date=July 2023}}<ref>{{cite journal |last1=Küssner |first1=Mats B. |title=Eysenck's Theory of Personality and the Role of Background Music in Cognitive Task Performance: A Mini-Review of Conflicting Findings and a New Perspective |journal=Frontiers in Psychology |date=2017 |volume=8 |page=1991 |doi=10.3389/fpsyg.2017.01991 |pmid=29184523 |pmc=5694457 |issn=1664-1078|doi-access=free }}</ref> A study also measured alertness with EEG data.{{elucidate|reason=what sort of EEG data indicates alertness? How is alertness measured with the data available from EEG readings?|date=July 2023}}<ref>{{cite journal |last1=Jagannathan |first1=Sridhar R. |last2=Ezquerro-Nassar |first2=Alejandro |last3=Jachs |first3=Barbara |last4=Pustovaya |first4=Olga V. |last5=Bareham |first5=Corinne A. |last6=Bekinschtein |first6=Tristan A. |title=Tracking wakefulness as it fades: Micro-measures of alertness |journal=NeuroImage |date=August 2018 |volume=176 |pages=138–151 |doi=10.1016/j.neuroimage.2018.04.046|pmid=29698731 |s2cid=13680412 }}</ref>
Additional information can be found on the neurobiology, neuroscience, brain, behavioral neuroscience, and neurotransmitter pages.
==Drugs used to increase alertness== The stimulant and adenosine receptor antagonist caffeine is widely used to increase alertness or wakefulness and improve mood or performance. People typically self-administer it in the form of drinks like green tea (where it is present alongside the l-theanine), energy drinks (often containing sugar/sugar-substitutes), or coffee (which contains various polyphenols). The chemicals that accompany caffeine in these preparations can potentially alter the alertness-promoting effects of caffeine.<ref>{{multiref2 |1={{Cite journal |last1=Owen |first1=Gail N. |last2=Parnell |first2=Holly |last3=De Bruin |first3=Eveline A. |last4=Rycroft |first4=Jane A. |date=August 2008 |title=The combined effects of L-theanine and caffeine on cognitive performance and mood |journal=Nutritional Neuroscience |volume=11 |issue=4 |pages=193–198 |doi=10.1179/147683008X301513 |issn=1476-8305 |pmid=18681988|s2cid=46326744 }} |2={{Cite journal |last1=Dodd |first1=F. L. |last2=Kennedy |first2=D. O. |last3=Riby |first3=L. M. |last4=Haskell-Ramsay |first4=C. F. |date=July 2015 |title=A double-blind, placebo-controlled study evaluating the effects of caffeine and L-theanine both alone and in combination on cerebral blood flow, cognition and mood |journal=Psychopharmacology |volume=232 |issue=14 |pages=2563–2576 |doi=10.1007/s00213-015-3895-0 |issn=1432-2072 |pmc=4480845 |pmid=25761837}} }}</ref> Caffeine is the world's most consumed stimulant drug.<ref>{{multiref2 |1={{Cite web |title=Caffeine |url=https://go.drugbank.com/drugs/DB00201#pharmacology |access-date=14 October 2020 |website=DrugBank.com}} |2={{cite journal |last1=Fiani |first1=Brian |last2=Zhu |first2=Lawrence |last3=Musch |first3=Brian L |last4=Briceno |first4=Sean |last5=Andel |first5=Ross |last6=Sadeq |first6=Nasreen |last7=Ansari |first7=Ali Z |title=The Neurophysiology of Caffeine as a Central Nervous System Stimulant and the Resultant Effects on Cognitive Function |journal=Cureus |date=14 May 2021 |volume=13 |issue=5 |article-number=e15032 |doi=10.7759/cureus.15032|doi-access=free |pmid=34150383 |pmc=8202818 |s2cid=235479155 }} |3={{cite journal |last1=Kennedy |first1=David O. |last2=Wightman |first2=Emma L. |title=Mental Performance and Sport: Caffeine and Co-consumed Bioactive Ingredients |journal=Sports Medicine |date=December 2022 |volume=52 |issue=S1 |pages=69–90 |doi=10.1007/s40279-022-01796-8|pmid=36447122 |pmc=9734217 }} |4={{cite journal |last1=Plumber |first1=Noorine |last2=Majeed |first2=Maliha |last3=Ziff |first3=Shawn |last4=Thomas |first4=Sneha E |last5=Bolla |first5=Srinivasa Rao |last6=Gorantla |first6=Vasavi Rakesh |title=Stimulant Usage by Medical Students for Cognitive Enhancement: A Systematic Review |journal=Cureus |date=22 May 2021 |volume=13 |issue=5 |article-number=e15163 |doi=10.7759/cureus.15163|doi-access=free |pmid=34178492 |pmc=8216643 }} |5={{cite journal |last1=Barcelos |first1=Rômulo P |last2=Lima |first2=Frederico D |last3=Carvalho |first3=Nelson R |last4=Bresciani |first4=Guilherme |last5=Royes |first5=Luiz FF |title=Caffeine effects on systemic metabolism, oxidative-inflammatory pathways, and exercise performance |journal=Nutrition Research |date=August 2020 |volume=80 |pages=1–17 |doi=10.1016/j.nutres.2020.05.005|pmid=32589582 |s2cid=219416791 |doi-access=free }} }}</ref>
Various natural biochemicals and herbs may have similar anti-fatigue effects, such as rhodiola rosea.<ref>{{multiref2 |1={{cite journal |last1=Chiang |first1=Hsiu-Mei |last2=Chen |first2=Hsin-Chun |last3=Wu |first3=Chin-Sheng |last4=Wu |first4=Po-Yuan |last5=Wen |first5=Kuo-Ching |title=Rhodiola plants: Chemistry and biological activity |journal=Journal of Food and Drug Analysis |date=September 2015 |volume=23 |issue=3 |pages=359–369 |doi=10.1016/j.jfda.2015.04.007|pmid=28911692 |pmc=9351785 }} |2={{cite journal |last1=Khanum |first1=Farhath |last2=Bawa |first2=Amarinder Singh |last3=Singh |first3=Brahm |title=Rhodiola rosea: A Versatile Adaptogen |journal=Comprehensive Reviews in Food Science and Food Safety |date=July 2005 |volume=4 |issue=3 |pages=55–62 |doi=10.1111/j.1541-4337.2005.tb00073.x |pmid=33430554 |language=en |issn=1541-4337}} }}</ref> Various psychostimulants like bromantane have also been investigated as potential treatments for conditions where fatigue is a primary symptom.<ref>{{cite journal |last1=Gill |first1=G |title=Performance-Enhancing Drugs: A Review |journal=UNM Orthopaedic Research Journal |date=1 January 2017 |volume=6 |issue=1 |url=https://digitalrepository.unm.edu/unm_jor/vol6/iss1/16/ |issn=2167-4760}}</ref> The alkaloids theacrine and methylliberine are structurally similar to caffeine and preliminary research supports their pro-alertness effects.<ref>{{cite journal |last1=Sheng |first1=Yue-Yue |last2=Xiang |first2=Jing |last3=Wang |first3=Ze-Shi |last4=Jin |first4=Jing |last5=Wang |first5=Ying-Qi |last6=Li |first6=Qing-Sheng |last7=Li |first7=Da |last8=Fang |first8=Zhou-Tao |last9=Lu |first9=Jian-Liang |last10=Ye |first10=Jian-Hui |last11=Liang |first11=Yue-Rong |last12=Zheng |first12=Xin-Qiang |title=Theacrine From Camellia kucha and Its Health Beneficial Effects |journal=Frontiers in Nutrition |date=2020 |volume=7 |article-number=596823 |doi=10.3389/fnut.2020.596823 |pmid=33392238 |pmc=7773691 |issn=2296-861X|doi-access=free }}</ref>
During the Second World War, U.S. soldiers and aviators were given benzedrine, an amphetamine drug, to increase their alertness during long periods on duty. While air force pilots{{Where|date=July 2023}} are able to use the drug to remain awake during combat flights, the use of amphetamines by commercial airline pilots is forbidden.{{Where|date=July 2023}}{{cn|reason=This isn't true. Amphetamine was removed as an approved go pill around the 2000s. Modafinil is the only prescription stimulant drug officially sanctioned for use by U.S. air force pilots. If you are referring specifically to WW2, change this sentence to past tense and add a source.|date=July 2023}} British troops used 72 million amphetamine tablets in the second world war<ref>{{Cite book |last=Mondenard De Monie |first=Jean-Pierre |title=Dopage: l'imposture des performances: mensonges et vérités sur l'école de la triche |year=2000 |publisher=Chiron éd. |isbn=978-2-7027-0639-8 |oclc=997463239}}</ref> and the Royal Air Force used so many that "Methedrine won the Battle of Britain" according to one report.<ref>Grant, D.N.W.; ''Air Force, UK, 1944''</ref>{{attribution needed|reason=source vaguely described; unable to find this title|date=July 2023}} American bomber pilots used amphetamines ("go pills") to stay awake during long missions. The Tarnak Farm incident, in which an American F-16 pilot killed several friendly Canadian soldiers on the ground, was blamed by the pilot on his use of amphetamine. A nonjudicial hearing rejected the pilot's claim.
Amphetamine is a common study aid among college and high-school students.<ref>{{Cite web |last=Twohey |first=Megan |date=2006-03-25 |title=Pills become an addictive study aid |url=http://www.jsonline.com/story/index.aspx?id=410902 |archive-url=https://web.archive.org/web/20070815200239/http://www.jsonline.com/story/index.aspx?id=410902 |archive-date=2007-08-15 |access-date=2007-12-02 |publisher=JS Online}}</ref> Amphetamine increases energy levels, concentration, and motivation, allowing students to study for an extended period of time.<ref>{{Cite journal |last1=Dlugos |first1=Andrea M |last2=Hamidovic |first2=Ajna |last3=Hodgkinson |first3=Colin A |last4=Goldman |first4=David |last5=Palmer |first5=Abraham A |last6=de Wit |first6=Harriet |date=2009-11-04 |title=More Aroused, Less Fatigued: Fatty Acid Amide Hydrolase Gene Polymorphisms Influence Acute Response to Amphetamine |journal=Neuropsychopharmacology |volume=35 |issue=3 |pages=613–622 |doi=10.1038/npp.2009.166 |pmid=19890266 |issn=0893-133X|pmc=2945903 }}</ref> These drugs are often acquired through diverted prescriptions of medication used to treat ADHD, acquired from fellow students, rather than illicitly produced drugs.<ref>{{Cite book |url=http://www.cmc.qld.gov.au/data/portal/00000005/content/63420001125986217865.pdf |title=The Illicit Market for ADHD Prescription Drugs in Queensland |date=April 2002 |publisher=Queensland Crime and Misconduct Commission |access-date=2008-01-13 |archive-url=https://web.archive.org/web/20090515072103/http://www.cmc.qld.gov.au/data/portal/00000005/content/63420001125986217865.pdf |archive-date=2009-05-15 }}</ref> Cocaine is also used to increase alertness,<ref>{{Cite web |date=4 July 2014 |title=Cocaine use rising among Hawaii workers, job applicants, lab says |url=http://www.bizjournals.com/pacific/news/2014/07/04/cocaine-use-rising-among-hawaii-workers-job.html |website=Pacific Business News}}</ref> and cocaine-related alkaloids present in coca tea.<ref>{{cite book |last1=Chen |first1=Cheng |last2=Lin |first2=Ligen |title=Handbook of Dietary Phytochemicals |chapter=Alkaloids in Diet |date=2019 |pages=1–35 |doi=10.1007/978-981-13-1745-3_36-1 |publisher=Springer |isbn=978-981-13-1745-3 |s2cid=214115630 |language=en}}</ref><ref name=jenkins>{{cite journal|vauthors=Jenkins AJ, Llosa T, Montoya I, Cone EJ | title=Identification and quantitation of alkaloids in coca tea. | journal=Forensic Sci Int | year= 1996 | volume= 77 | issue= 3 | pages= 179–89 | pmid=8819993 | pmc=2705900 | doi=10.1016/0379-0738(95)01860-3 }}</ref>
The eugeroic modafinil has recently gained popularity with the US Military<ref>{{Cite web |title=Defense Technical Information Center Compilation Part Notice ADPO 11050 |url=http://apps.dtic.mil/dtic/tr/fulltext/u2/p011050.pdf |url-status=live |archive-url=https://web.archive.org/web/20160304042132/http://www.dtic.mil/dtic/tr/fulltext/u2/p011050.pdf |archive-date=March 4, 2016 |website=dtic.mil |publisher=Defense Technical Information Center}}</ref>{{Vague|reason=Popularity at what level?|date=October 2020}} and other militaries.
==Other approaches for increasing alertness== Beyond good sleep, physical activity, and healthy diet, a review suggests odours, music, and extrinsic motivation may increase alertness or decrease mental fatigue.<ref>{{cite journal |last1=Proost |first1=Matthias |last2=Habay |first2=Jelle |last3=De Wachter |first3=Jonas |last4=De Pauw |first4=Kevin |last5=Rattray |first5=Ben |last6=Meeusen |first6=Romain |last7=Roelands |first7=Bart |last8=Van Cutsem |first8=Jeroen |title=How to Tackle Mental Fatigue: A Systematic Review of Potential Countermeasures and Their Underlying Mechanisms |journal=Sports Medicine |date=September 2022 |volume=52 |issue=9 |pages=2129–2158 |doi=10.1007/s40279-022-01678-z|pmid=35543922 |s2cid=248672972 }}</ref> Short rest periods and adjustments to lighting (level and type of) may also be useful.<ref>{{cite journal |last1=Bonnefond |first1=Anne |last2=Tassi |first2=Patricia |last3=Roge |first3=Joceline |last4=Muzet |first4=Alain |title=A Critical Review of Techniques Aiming at Enhancing and Sustaining Worker's Alertness during the Night Shift |journal=Industrial Health |date=2004 |volume=42 |issue=1 |pages=1–14 |doi=10.2486/indhealth.42.1|pmid=14964612 |doi-access=free |bibcode=2004IndHe..42....1B }}</ref> Various types of neurostimulation are being researched,<ref>{{cite journal |last1=Bagary |first1=Manny |title=Epilepsy, Consciousness and Neurostimulation |journal=Behavioural Neurology |date=2011 |volume=24 |issue=1 |pages=75–81 |doi=10.3233/BEN-2011-0319|pmid=21447901 |pmc=5377955 }}</ref>{{explain|date=January 2023}} as is the microbiome and related interventions.<ref name="10.3920/BM2021.0122"/>
==Alertness after waking== A study suggests non-genetic determinants of alertness upon waking up from sleep are:<ref>{{cite news |title=What are the factors that affect how alert we feel in the morning? |url=https://www.medicalnewstoday.com/articles/feeling-tired-in-the-morning-4-factors-are-key-to-alertness-levels |access-date=13 December 2022 |work=www.medicalnewstoday.com |date=29 November 2022 |language=en}}</ref><ref name="10.1038/s41467-022-34503-2">{{cite journal |last1=Vallat |first1=Raphael |last2=Berry |first2=Sarah E. |last3=Tsereteli |first3=Neli |last4=Capdevila |first4=Joan |last5=Khatib |first5=Haya Al |last6=Valdes |first6=Ana M. |last7=Delahanty |first7=Linda M. |last8=Drew |first8=David A. |last9=Chan |first9=Andrew T. |last10=Wolf |first10=Jonathan |last11=Franks |first11=Paul W. |last12=Spector |first12=Tim D. |last13=Walker |first13=Matthew P. |title=How people wake up is associated with previous night's sleep together with physical activity and food intake |journal=Nature Communications |date=19 November 2022 |volume=13 |issue=1 |page=7116 |doi=10.1038/s41467-022-34503-2 |pmid=36402781 |pmc=9675783 |bibcode=2022NatCo..13.7116V |language=en |issn=2041-1723|doi-access=free}}</ref> * sleep quantity/quality the night before * physical activity the day prior * a carbohydrate-rich breakfast * a lower blood glucose response following breakfast **(modifiable as well, for example via choice of food and with berberine<ref>{{multiref2 |1={{cite journal |last1=Liang |first1=Yaping |last2=Xu |first2=Xiaojia |last3=Yin |first3=Mingjuan |last4=Zhang |first4=Yan |last5=Huang |first5=Lingfeng |last6=Chen |first6=Ruoling |last7=Ni |first7=Jindong |title=Effects of berberine on blood glucose in patients with type 2 diabetes mellitus: a systematic literature review and a meta-analysis |journal=Endocrine Journal |date=2019 |volume=66 |issue=1 |pages=51–63 |doi=10.1507/endocrj.EJ18-0109|pmid=30393248 |s2cid=53218338 |hdl=2436/621980 |hdl-access=free }} |2={{cite journal |last1=Ilyas |first1=Zahra |last2=Perna |first2=Simone |last3=Al-thawadi |first3=Salwa |last4=Alalwan |first4=Tariq A. |last5=Riva |first5=Antonella |last6=Petrangolini |first6=Giovanna |last7=Gasparri |first7=Clara |last8=Infantino |first8=Vittoria |last9=Peroni |first9=Gabriella |last10=Rondanelli |first10=Mariangela |title=The effect of Berberine on weight loss in order to prevent obesity: A systematic review |journal=Biomedicine & Pharmacotherapy |date=July 2020 |volume=127 |article-number=110137 |doi=10.1016/j.biopha.2020.110137|pmid=32353823 |s2cid=218468722 |hdl=2434/956124 |hdl-access=free }} |3={{cite journal |last1=Xie |first1=Wenting |last2=Su |first2=Fugui |last3=Wang |first3=Guizhong |last4=Peng |first4=Zichong |last5=Xu |first5=Yaomin |last6=Zhang |first6=Yi |last7=Xu |first7=Ningning |last8=Hou |first8=Kaijian |last9=Hu |first9=Zhuping |last10=Chen |first10=Yan |last11=Chen |first11=Rongping |title=Glucose-lowering effect of berberine on type 2 diabetes: A systematic review and meta-analysis |journal=Frontiers in Pharmacology |date=16 November 2022 |volume=13 |article-number=1015045 |doi=10.3389/fphar.2022.1015045|pmid=36467075 |pmc=9709280 |doi-access=free}} }}</ref>)
The {{tooltip|baseline level|the stable level around which the moment-to-moment wakefulness fluctuates and the starting point which can be changed with interventions}} of daily alertness is related to the quality of sleep (in the 2022 study measured only by self-reported quality), positive emotional state (specifically self-report happiness), and age.<ref name="10.1038/s41467-022-34503-2"/> There are genes that enable people to be apparently healthy and alert with little sleep. However, twin-pair analyses indicate that the genetic contribution to daytime alertness is small.<ref name="10.1038/s41467-022-34503-2"/> Other factors such as natural light exposure<ref name="10.1038/s41467-022-34503-2"/> and synchronicity with the circadian rhythm may matter as well.
==Behavioral ecology== Vigilance is important for animals so that they may watch out for predators. Typically a reduction in alertness is observed in animals that live in larger groups. Studies on vigilance have been conducted on various animals including the scaly-breasted munia.<ref>{{Cite journal |last1=Roche |first1=Erin A. |last2=Brown |first2=Charles R. |date=December 2013 |title=Among-individual variation in vigilance at the nest in colonial Cliff Swallows |url=https://bioone.org/journals/the-wilson-journal-of-ornithology/volume-125/issue-4/12-196.1/Among-individual-variation-in-vigilance-at-the-nest-in-colonial/10.1676/12-196.1.full |journal=The Wilson Journal of Ornithology |volume=125 |issue=4 |pages=685–695 |doi=10.1676/12-196.1 |issn=1559-4491 |s2cid=13865609|url-access=subscription }}</ref>
== See also== *{{annotated link|Awareness}} *{{annotated link|Consciousness}} *{{annotated link|Disorders of consciousness}} *{{annotated link|Wakefulness}}
==References== {{reflist|30em}}
{{Virtues}}
Category:Attention Category:Cognitive neuroscience Category:Mental states