The change from visible to invisible:

It is argued that the problem of the phenomenal persistence of objects in experience, often called “object permanence,” is actually a problem of the discriminating of persisting from nonpersisting things. A distinction is made between objects that go out of sight and objects that go out of existence, and it is shown that optical information exists to distinguish these two cases. Evidence is provided from a series of motion picture displays to suggest that Os do in fact distinguish them. The various optical transitions are shown to be reversing in the first case, but nonreversing in the second. In particular, the transition that specifies the occlusion of one surface by another is analyzed, together with the inverse of this transition. This study is a sequel to an earlier one of optical transformations.     

Separating the effects of interreinforcement time and number of interreinforcement responses

The relative importance of interreinforcement time and interreinforcement responses was evaluated by varying each independently. To do this, a blackout was presented after each nonreinforced response under both fixed-ratio and fixed-interval schedules of reinforcement. Manipulating the blackout duration under the fixed-ratio schedule caused interreinforcement time to vary without affecting the number of interreinforcement responses. Pigeons' post-reinforcement and post-blackout response latencies were found to increase linearly with interreinforcement time. Under the fixed-interval schedule, the same blackout manipulations changed the number of interreinforcement responses without affecting interreinforcement time. Post-reinforcement and post-blackout response latencies under this condition were approximately constant. These results suggest that responding is controlled by interreinforcement time and is not influenced by the number of responses emitted between reinforcements.     

Choice between two-component chained and tandem schedules

Pigeons were trained on a two-key choice procedure in which a pair of equal and concurrently available variable-interval schedules (initial links) arranged entry into one or the other of two mutually exclusive schedules (terminal links) that ended in primary reinforcement. The terminal links were two-component chained or tandem schedules. Responses during the initial links were distributed equally on the two keys whenever the terminal links were associated with the same sets of interreinforcement intervals. Whether or not the terminal-link interreinforcement intervals were the same on the two keys, initial-link responding was affected by neither the presence nor relative durations of differentially signalled components within a terminal-link schedule. The simplest interpretation of these results is that initial-link responding is maintained directly by delayed primary reinforcement, rather than conditioned reinforcement afforded by the stimuli correlated with the terminal-link schedule components. This finding suggests that aspects of chained schedule performance usually attributed to conditioned reinforcement might best be reinterpreted in terms of delayed primary reinforcement and various discriminative functions served by the component-correlated stimuli.     

Multidimensional scaling of color difference in the pigeon

Pigeons were required to discriminate between “identical” vs “different” pairs of lights in a yes/no signal-detection task with a symmetrical payoff matrix. If the two lights projected on the two halves of the bipartite field constituting the center response key in a three-key chamber were identical in wavelength composition, a single peck on the right key was reinforced with food. If the two lights differed in wavelength composition, then left-key pecks were reinforced. In Experiment 1, each of six pigeons experienced all possible pairs of 11 spectral lights and 1 purple light (66 pairs). In Experiment 2, the set of lights was expanded to 15 (105 pairs) and included a white light. The percentage of correct choices was taken as an index of the dissimilarity between the two lights constituting a pair. The rank-order information available in these dissimilarity measures was used to determine coordinate projections for each light in a two-dimensional Euclidean space. The configuration obtained in this manner was interpreted as a color circle for the pigeon.     

The use of a token system in project Head Start

The present experiment sought to develop a practical and effective method for teaching the beginning elements of hand-writing in a Head Start program. The method consisted of reinforcing responses to a writing program by giving the children access to a variety of activities normally available in the pre-school classroom. Tokens were presented for correct responses. The children then used the tokens to select reinforcers, such as snacks and access to a variety of play activities. In an experimental evaluation of the token system, it was found that responding was maintained as long as access to the reinforcing activities was contingent upon responding. When reinforcement was no longer contingent upon responding, virtually no responding occurred. Informal observations suggested that the token system had several unanticipated effects: the children's vocabulary and ability to understand instructions improved; a favorable attitude toward school developed; and their ability to play cooperatively with other children increased. It was concluded that the token system is a practical and effective method for teaching beginning writing skills and that it has other desirable, if unanticipated, effects.     

Effect of presentation order on the construction of linear orders

Subjects constructed four-term linear orders from three sentences expressing the relationships between adjacent elements in the order. Successful performance was more likely when the second sentence introduced only one element not mentioned in the first sentence rather than two new elements and when the second and third sentences introduced new elements as grammatical subjects rather than objects. Except for the latter result, previously proposed theories of reasoning processes primarily in three-term series problems, predict other differences that failed to appear. Apparently, in longer series, memory limitations favor conditions in which each sentence after the first presents a relationship between a new and an old element in linguistic forms that identify the new element.