Simple schedules

A chart demonstrating the different response rate of the four simple schedules of reinforcement, each hatch mark designates a reinforcer being given

Simple schedules have a single rule to determine when a single type of reinforcer is delivered for specific response.

• Fixed ratio (FR) schedules deliver reinforcement after every nth response
  • Example: FR2 = every second response is reinforced
  • Lab example: FR5 = rat reinforced with food after each 5 bar-presses in a Skinner box.
  • Real-world example: FR10 = Used car dealer gets a $1000 bonus for each 10 cars sold on the lot.
• Continuous ratio (CRF) schedules are a special form of a fixed ratio. In a continuous ratio schedule, reinforcement follows each and every response.
  • Lab example: each time a rat presses a bar it gets a pellet of food
  • Real world example: each time a dog defecates outside its owner gives it a treat
• Fixed interval (FI) schedules deliver reinforcement for the first response after a fixed length of time since the last reinforcement, while premature responses are not reinforced.
  • Example: FI1" = reinforcement provided for the first response after 1 second
  • Lab example: FI15" = rat is reinforced for the first bar press after 15 seconds passes since the last reinforcement
  • Real world example: FI24 hour = calling a radio station is reinforced with a chance to win a prize, but the person can only sign up once per day
• Variable ratio (VR) schedules deliver reinforcement after a random number of responses (based upon a predetermined average)
  • Example: VR3 = on average, every third response is reinforced
  • Lab example: VR10 = on average, a rat is reinforced for each 10 bar presses
  • Real world example: VR37/VR38 = a roulette player betting on specific numbers will win on average once every 37 or 38 tries, depending on whether the wheel has a 00 slot.
• Variable interval (VI) schedules deliver reinforcement for the first response after a random average length of time passes since the last reinforcement
  • Example: VI3" = reinforcement is provided for the first response after an average of 3 seconds since the last reinforcement.
  • Lab example: VI10" = a rat is reinforced for the first bar press after an average of 10 seconds passes since the last reinforcement
  • Real world example: a predator can expect to come across a prey on a variable interval schedule

Other simple schedules include:

• Differential reinforcement of incompatible behavīor (DRI) is used to reduce a frequent behavīor without punishing it by reinforcing an incompatible response. An example would be reinforcing clapping to reduce nose picking.
• Differential reinforcement of other behavīor (DRO) is used to reduce a frequent behavīor by reinforcing any behavīor other than the undesired one. An example would be reinforcing any hand action other than nose picking.
• Differential reinforcement of low response rate (DRL) is used to encourage low rates of responding. It is like an interval schedule, except that premature responses reset the time required between behavīor.
  • Lab example: DRL10" = a rat is reinforced for the first response after 10 seconds, but if the rat responds earlier than 10 seconds there is no reinforcement and the rat has to wait 10 seconds from that premature response without another response before bar pressing will lead to reinforcement.
  • Real world example: "If you ask me for a potato chip no more than once every 10 minutes, I will give it to you. If you ask more often, I will give you none."
• Differential reinforcement of high rate (DRH) is used to increase high rates of responding. It is like an interval schedule, except that a minimum number of responses are required in the interval in order to receive reinforcement.
  • Lab example: DRH10"/15 responses = a rat must press a bar 15 times within a 10 second increment in order to be reinforced
  • Real world example: "If Lance Armstrong is going to win the Tour de France he has to pedal x number of times during the y hour race."
• Fixed Time (FT) provides reinforcement at a fixed time since the last reinforcement, irrespective of whether the subject has responded or not. In other words, it is a non-contingent schedule

• • Lab example: FT5": rat gets food every 5" regardless of the behavīor.
  • Real world example: a person gets an annuity check every month regardless of behavīor between checks
• Variable Time (VT) provides reinforcement at an average variable time since last reinforcement, regardless of whether the subject has responded or not.

[edit]Effects of different types of simple schedules

• Ratio schedules produce higher rates of responding than interval schedules, when the rates of reinforcement are otherwise similar.
• Variable schedules produce higher rates and greater resistance to extinction than most fixed schedules. This is also known as the Partial Reinforcement Extinction Effect (PREE)
• The variable ratio schedule produces both the highest rate of responding and the greatest resistance to extinction (an example would be the behavīor of gamblers at slot machines)
• Fixed schedules produce 'post-reinforcement pauses' (PRP), where responses will briefly cease immediately following reinforcement, though the pause is a function of the upcoming response requirement rather than the prior reinforcement.
  • The PRP of a fixed interval schedule is frequently followed by an accelerating rate of response which is "scallop shaped," while those of fixed ratio schedules are more angular.
• Organisms whose schedules of reinforcement are 'thinned' (that is, requiring more responses or a greater wait before reinforcement) may experience 'ratio strain' if thinned too quickly. This produces behavīor similar to that seen during extinction.
• Partial reinforcement schedules are more resistant to extinction than continuous reinforcement schedules.
  • Ratio schedules are more resistant than interval schedules and variable schedules more resistant than fixed ones.

[edit]Compound schedules

Compound schedules combine two or more different simple schedules in some way using the same reinforcer for the same behaviour. There are many possibilities; among those most often used are:

• Alternative schedules - A type of compound schedule where two or more simple schedules are in effect and which ever simple schedule is completed first results in reinforcement. ^[15]
• Conjunctive schedules - A complex schedule of reinforcement where two or more simple schedules are in effect independently of each other and requirements on all of the simple schedules must be met for reinforcement.
• Multiple schedules - either of two, or more, schedules may occur with a stimulus indicating which is in force.
  • Example: FR4 when given a whistle and FI 6 when given a bell ring.
• Mixed schedules - either of two, or more, schedules may occur with no stimulus indicating which is in force.
  • Example: FI6 and then VR 3 without any stimulus warning of the change in schedule.
• Concurrent schedules - two schedules are simultaneously in force though not necessarily on two different response devices, and reinforcement on those schedules is independent of each other.
• Interlocking Schedules - A single schedule with two components where progress in one component affects progress in the other component. An interlocking FR60-FI120, for example, each response subtracts time from the interval component such that each response is "equal" to removing two seconds from the FI.
• Chained schedules - reinforcement occurs after two or more successive schedules have been completed, with a stimulus indicating when one schedule has been completed and the next has started.
  • Example: FR10 in a green light when completed it goes to a yellow light to indicate FR 3, after it's completed it goes into red light to indicate VI 6, etc. At the end of the chain, a reinforcer is given.
• Tandem schedules - reinforcement occurs when two or more successive schedule requirements have been completed, with no stimulus indicating when a schedule has been completed and the next has started.
  • Example: VR 10, after it is completed the schedule is changed without warning to FR 10, after that it is changed without warning to FR 16, etc. At the end of the series of schedules, a reinforcer is finally given.
• Higher order schedules - completion of one schedule is reinforced according to a second schedule; e.g. in FR2 (FI 10 secs), two successive fixed interval schedules would have to be completed before a response is reinforced.

薩特的哲學是一種激進的自由意志主義。這種理論和決定論相對，認為人類有絕對的自由。「上帝已死」，尼采名言可以看作薩特哲學的一個基本前提。結果是人變成被拋棄的了。因為在人的身內身外，都無法找到依託的東西。人沒有存在的理由。而如果確實是存在先於本質，人就不能用一種天生的現有的人性來解釋自己的行動；也就是說，沒有決定論。人是自由的。人就是自由。另一方面，如果上帝不存在，人就沒有價值和戒律說明人的行為是正當的。沒有價值領域。人孤寂獨處，無可辯解。這就是薩特說「人是被判定為自由」時想要表達的意思。因為一個人並不是自願存在於世的，然而一旦存在，他就是自由的；但同時他要對自己所做的一切負責。

「上帝已死」雖是薩特哲學的一個基本前提——但跟同時代的西方作家一樣，在其的思想中也帶有「上帝」的影子。有學者認為，其是「反有神論」者，而不是持「無神論」。隨之而來的問題可以借俄國作家杜斯妥也夫斯基在《卡拉瑪左夫兄弟》一書中提出的問題「如果沒有上帝，那麼所有事情都是允許的。」這句話來表達。要理解薩特的自由，我們要知道另外兩個重要的概念：自在（l'en-soi），或自在的存在；自為（le pour-soi），自為的存在。「自在」是「是其所是」，「自為」是「是其所不是」。舉一個例子，刀子的存在是為了切割東西，它的存在有一個目的；然而人類的存在並沒有任何目的――因為「上帝已死」――所以人類要為自己的存在創造價值。因此「存在先於本質」。人是面向未來，具備無限可能的「自為」主體，而不是封閉的。薩特又提到了「焦慮」和「眩暈」。薩特認為，人們感到焦慮，恰恰是因為人們的自由，人們感到了自由，但是無從選擇。比如一個大學三年級的學生面臨攻讀研究生和就業之間的選擇。他不能依賴任何東西作出選擇，包括上帝，這樣便沒有任何因素使得他的選擇成為一個必然。繼續學業或就業，一切都要靠自己。而「眩暈」則是「焦慮」的一種，人們在懸崖旁感到眩暈，是因為他意識到自己可以選擇自殺――跳下去，而跳與不跳都由一個人自己決定。這是人類自由的表現。在「眩暈」這個例子裡面，我們可以看到薩特的另外一個重要概念：「超越性」。超越性表現在人類在有多個選擇的時候可以設想每個可能的後果，這樣人類能夠自己做出選擇。

薩特的另外一個概念是所謂「自欺」。他把「自欺」描述為「半透明狀態」，他對自欺的描述可以跟其對潛意識的反駁聯繫起來理解。他否認潛意識的存在，以為不過是一種「自欺」。這也可以跟其對「本質」，「中心」的反感聯繫在一起。他不認為存在什麼超驗的「本質」，因而人是「必然自由」的。他認為自欺是人對自己的自由的逃避和否定造成的。一個著名的例子是，一個女人和一個男人約會，女人很清楚男人懷有親近她的企圖。因為她的自由，她必須在順從和拒絕之間做出選擇，可是她故意否定自己的這個自由，男人說的每一句話，她只理解其中的表面含義。

她不想理解人家對她說的話的言外之意，如果人家對她說：「我如此的欽慕您」，她消除了這句話深處的性的含義……與她說話的人在她看來似乎是真誠和恭敬的，就和桌子是圓的或方的，牆紙是藍的或灰的一樣。（p.90《存在與虛無》，三聯出版社，1998）

另外一個隨之而來的問題有關人類的責任。一個人在做出選擇的同時，他也向其他人推薦他的選擇。他有選擇的自由，也就要為所有的後果承擔責任。一個例子是在二戰時期的某個法國家庭里，父親為德國人工作，兩個兒子中大兒子去世了，小兒子留在母親身邊。小兒子知道自己對母親非常重要，不能離開她。但是另一方面，作為一個法國人，他希望到英國參加法國的抵抗力量，解放自己的祖國並為哥哥報仇。這樣，小兒子陷入了一個進退兩難的境地，他去問薩特。而得到的回答是，你自己選擇，無論後果如何，你都要為其承擔責任。晚期，他的思想有所改變，把目光更多的放在社會這個宏觀的層面上。也開始承認，自由本身是有所限制的，要人為自己的行為負責，也是難以實現的。他嘗試對馬克思哲學進行改變，把馬克思哲學和人學聯繫起來。 其思想內容比較豐富，若想全面理解，還需要對海德格爾對「存在」的分析和胡塞爾的「意向性」結構分析進行研讀。而對物質世界，他持一種模糊的，但又直接的實在論觀點。他受過德國哲學的熏陶，行文上頗為晦澀。其哲學具有鮮明的個人特色。

虛無 (Nothingness)

「虛無」（nothingness）是人的意識作為「對己存有」(For-Itself) 之根本特質，人在朝向未來, 投射出理想的自我之時，他便不再只是 當下的自己，這時, 他從理想的狀態回頭看自己, 而否定眼前的自己。

否定自己, 就是將眼前的自己虛無化。但是, 人們藉以否定當下狀態的理想既然尚未實現，所以也是一種虛無。如此一來，人生徹頭徹尾都被虛無所貫穿。然而, 虛無不表示否定生命的意義。

相反地，薩特認為, 這樣才能肯定人之為人的意義。因為, 假若人只是固定不變的物體，則他將任人擺佈，這難道不是對人最大的否定嗎？或許我們用「 缺如 」(lack) 來解釋「虛無」的涵義會更為恰當。當人心中有個理想，因而對照出現狀的種種缺失時，他就是處於一種 「 缺如 」(lack) 的狀態。

因此無所謂人性，因為沒有上帝 去創造這個概念，人赤裸裸地存在。他不是想像中 ( conceive ) 的自己，而是意欲 ( will ) 成甚麼才是甚麼；他存在之後，才能想像他自己是甚麼，這是在他 躍進存在之後意欲的 ( what he wills himself to be after this thrust toward existence )，人除自我塑造之外甚麼也不是。 ( Man is nothing else but what he makes of himself. )

– 薩特 , << 存在主義是一種人文主義 >>