10 (47)

id, whilc tlic mtrucclluiar llmd remamed wacer-Uepnveu. Agam, :he rats drank moro chan nornial. Thercforc, Mook anc! Kozub dis thcmse)vcs must liouse a ncgativc fcedback niechanism for ,i>ic from cach of tłicsc threc studios implies char thrco scparacc dback mcchanisms cxisc—one in chc mouth, one in che stornach,

lfluences

availability, niemory of thc clapscd tinie sińce thc lasc drink, and rorganismic mcchanisms of drinking behavior. As co watcr avail-havior dcpcnds on chc amounc of watcr in tlić animals cnviron-tube for a laboratory animal, Toaccs, 1979). Animals wieli watcr-icnts drink less chan do animals with watcr-restricted environ-ory sińce chat lasc drink, Toaccs also found char animals acquirc to drinking schcdules, irrcspcccive of lcvcls of bodily fluids and

portanc environniental influence, or cxtraorganismic rr.chanism, 'ior is tasce (Pfaffmann, 1961, 1982). Purc wacer is cascelcss; ic there-' :ntivc value bcyond watcr rcplenishmcnc. When watcr is given a nking bchavior changes in accordancc with the incentivc value of J.shows a graph of thc incentivc value of four tastes: sweet, sour, iphcd ac various scimulus inccnsities. Using cascelcss water as a basc-icss), any tastc is at least slightly plcasant at very Iow scimulus inten-istantial incctisitics, sucrose-flavorcd (sweet) water is markcdly morę seeless watcr. Tarcic acid- (sour), salt-, and quinine- (bicccr) fiavorcd cccily morę unpleasant than cascelcss watcr. If we wcrc to provide ir typcs of flavorcd wacer to cxpcrimcntal parcicipants, drinking crtainly vary as a function of thc pleasantness of che water's tasce. ors such as a sweet tastc offer a high inccncive value for drinking, ink cxccssivcly and somccimcs dangcrously, biologically speaking ). Thus, drinking behavior occurs for two rcasons, noc just one: (1) ent, and (2) subjcctivc sensations of plcasure.’

HUNGER

: coniplcx regulatory motivc than is thirst. Loss of water inseigates .•plcnishmcnt satiates thirst. Hunger, one miglic thercforc think, lical loss and rcplcnishment of food. Hunger, howevcr, must be ooth short-term and long-term rcgulaced. Hunger rcgulation, as wc ccraction becween short-ccrni proccsscs operating under lionicostatic

twcen tastc and drinltinc bchavior is mado morc complicatcd by tbc face chat watcr ,c pcrccption of ibc tastc of watcr. Watcr bccomcs incrcasingly morc bcdonically pos-with inerejsed dcptivation, and watcr bccomcs incrcasinyly morc bcdonically ;>vcr-ion (Ucck, 1979).

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f Y Y

Degree of Pleasantncss ofFour Diffcrcnt Taste Solutions

Sourco: Pfoitmann (1960).

regulation (c.g., caloric incakc) and long-tcrm proccsscs opcrac(ngunder metabolit' regulation (c.g., mccabolism and fai; cclls). To complicarc. our pictuj«fjiirc|vcr, l\unger and cating bchavior arc strongly afTectcd by Icarmng and-cnviron^ńcal-<n(liiencis, so much in fact thac an understanding of hunger rccjuires both pb^1 bIogića11y• ba.^cd and cnvironmcncally-bascd modcls (Wcingarccn, 1'9,Ś5).    k ¹    t

Physiological-Regulation    '* i. *

Hunger arises from both brain and pcriphcral (non-braiń) bodily cues. The Kiaj r brain hunger cue is chc laccral hypochalamus (LH)..Dclgado and Anand (1953), instancc, had rats eac their cypical dailymcal and then-clectrically stimuj^tet^rlv.ii latcral hypochalamic nucleus. Stimulacion (of their ,LH produeed cxtonsivc e ;ng bchavior, despite thc fact thac cach animal-had just caten to saciccy. Just .is the I; ■ ■ il