Stochastic transitivity and the unidimensional control of choice

A concurrent-chains paradigm was used to test three models of preference for schedules of reinforcement. Each model assumes choice to be a monotonic function of values on a single dimension (“simple scalability”). For choices involving variable-interval and fixed-interval schedules, this dimension is assumed to be an harmonic average of the interreinforcement intervals; for choices involving fixedinterval and fixed-ratio schedules, the dimension is the time to reinforcement irrespective of response rate; for choices involving different combinations of rate and duration of reinforcement, the dimension is the rate of “reinforcement-time”, or the product of the two parameters. Each model implies a strong form of transitivity (“functional equivalence”), which held for half the subjects (that half exclusively sensitive to the reinforcement variable specified by the model). An alternative unidimensional model which implies a weaker form of transitivity (“weak binary utility model”) was consistent with the preferences of all subjects. This model states that a single factor controls the direction of preferences but not necessarily the exact choice probability, as simple scalability assumes.     

"Automaintenance": the role of reinforcement

A key was illuminated on the average of every 30 sec for a duration of 6 sec and this was followed by food presentations. When key pecks in the presence of the light produced immediate access to grain (autoshaping procedure) pigeons were likely to peck. When pecks terminated the keylight but prevented access to grain (automaintenance procedure) pigeons were much less likely to peck. Seven of 12 pigeons failed to develop responding during the automaintenance procedure. Four of the five pigeons that responded during the automaintenance procedure were exposed to a procedure in which responses could not immediately terminate the light. Three of the four ceased to respond during optimal automaintenance conditions, suggesting that the response-dependent offset of the keylight had been reinforcing their pecking. Responding during the automaintenance procedure was eliminated for a fifth pigeon by eliminating the contiguity of light-offset and food-onset on those trials in which the pigeon did not peck. These results suggest that: (1) automaintenance (unlike autoshaping) is not an effective procedure for reliably generating responding; (2) responding that does occur during the automaintenance procedure is reinforced by the response-dependent offset of the keylight.     

Transitivity as a property of choice

Pigeons' pecks in the presence of two concurrently available initial-link stimuli occasionally produced one of two stimuli associated with mutually exclusive terminal links. Pecks during either terminal link produced food according to aperiodic (variable-interval and variable-ratio) or periodic (fixed-interval and fixed-ratio) schedules of reinforcement. Aperiodic and periodic schedules to which the pigeons were indifferent, in the sense that these schedules maintained equal responding in the initial links, often yielded different preferences in separate choice tests with a third schedule. Conversely, aperiodic and periodic schedules that were equally preferred to a third schedule often failed to generate indifference. These intransitivities imply that (1) aperiodic and periodic schedules are not functionally equivalent in their effects upon choice, and (2) efforts to find a simple method for transforming aperiodic schedules into their periodic equivalents will fail.     

Human Impulsivity and Choice: A Challenge to Traditional Operant Methodology

“Impulsivity” refers to the choice of an immediate, small reinforcer over a delayed, large reinforcer. Traditional operant methods (single-subject designs, free-operant choice procedures) have frequently been used to study impulsivity in nonhuman subjects but, curiously, have not been applied to humans. Data are reported replicating and extending previous results obtained with an alternative paradigm using a group-statistical design and discrete-trials choice procedure. Adults chose between schedules differing in delay and/or amount of reinforcement, the reinforcer being slides of entertainment and sports personalities. Delay was defined as the interval between a choice response and onset of a slide, amount as the duration of viewing time. Some participants exhibited impulsivity even though such behavior reduced total viewing time. All participants exhibited impulsivity when this behavior increased total viewing time and was thus adaptive. Traditional operant methods may be ineffective in producing the maladaptive form of impulsivity.

     

Historical Psychology and the Milgram Paradigm: Tests of an Experimentally Derived Model of Defiance Using Accounts of Massacres by Nazi Reserve Police Battalion 101

The Psychological Record - In Milgram’s (1963, 1965a, 1965b, 1974/2004) experiments on destructive obedience, an authority figure repeatedly ordered a resistant participant to deliver what...     

Negative reinforcement and choice in humans

Participants chose between reinforcement schedules differing in delay and/or duration of noise offset. In Experiment 1 it was found that (1) immediate reinforcement was preferred to delayed reinforcement when amounts (durations) of reinforcement were equal; (2) a relatively large reinforcer was preferred to a smaller one when both reinforcers were obtained immediately; and (3) preference for an immediate, small reinforcer versus a delayed, large reinforcer increased as the delay preceding the large reinforcer increased, a sign of “impulsivity”. In Experiment 2, the schedules differed in amount or delay and equal intervals were added either to the constant parameter or the varied parameter. A shift from virtually exclusive preference to indifference occurred in the latter case but not the former, a result supporting a model of self-control that assumes that the value of a schedule depends on the ratio of amount and delay, and that choice between schedules depends on the ratio of these values.     

Free-operant choice behavior: A molecular analysis

Pigeons' pecks to two concurrent initial-link stimuli occasionally produced one of two mutually exclusive terminal links. Further responding to the terminal-link stimulus produced food under fixed-interval or fixed-ratio schedules. In such concurrent chained schedules, investigators rarely use a changeover delay to control superstitious switching, although it is customary to use a changeover delay in simple concurrent schedules in which choice responses produce food directly. When terminal-link fixed-interval schedules were equal or similar in duration and no changeover delay was employed, conditional probabilities of choice for a schedule were found to be lower if the last choice was for that schedule than if the last choice was for the other schedule (“switching dependency”). Imposition of a changeover delay with equal or unequal terminal links produced the opposite pattern: conditional probabilities of choice for a schedule were higher if the last choice was for that schedule than if the last choice was for the other schedule. Turning off all chamber lights during the changeover delay interval attenuated these “repetition dependencies.” The results indicate that excessive switching can complicate the interpretation of data from concurrent chains much as from simple concurrent schedules, and that using blackouts to control switching may be preferable to using a changeover delay.     

Reviving the Milgram Obedience Paradigm in the Era of Informed Consent

The Psychological Record - Participants repeatedly chose between 25 s of cartoon video followed by 5 s of time-out and 5 s of cartoon video followed by 25 s of time-out. In the first 15 min,...     

Reinforcement Probability and Delay as Determinants of Human Impulsiveness

In behavior theory, “impulsiveness” refers to the choice of an immediate, small reinforcer over a delayed, large reinforcer. Such behavior generally is attributed to a reduction in the value of the large reinforcer as a function of the duration of delay. In contrast, social learning theorists have suggested that human impulsiveness can result from a lowered “expectancy” (subjective probability) of reinforcement. Effects of probability and delay were assessed by asking adults to make repeated choices between reinforcement schedules in which the reinforcers were slides of entertainment figures. An immediate, 5-s reinforcer was consistently chosen over an immediate, 40-s reinforcer if the probability of receiving the large reinforcer had previously been low (.20), implying that impulsiveness can occur without time-based discounting. However, reinforcement delay was also influential: Choice between a certain, small reinforcer and an uncertain, large reinforcer varied according to which reinforcer was immediate and which delayed.