The role of nonreinforcement in the learning of honeybees

Two series of experiments with honeybees were designed to test the assumption that inhibition is generated by nonreinforcement as a function of the excitatory value of the context. In the first series (Experiments 1-3), summation tests with B were made after A+/C-/AB- as compared to A+/C-/CB- training, with precautions taken to minimize the possibility of a masking effect of excitatory within-compound conditioning on AB trials; responding to B did not vary with training procedure. In the second series (Experiments 4-5), retardation tests rather than summation tests were used, in the belief that they might be more sensitive; after A+/AB-/CD- training, acquisition in a B+/D- problem was found to be no less rapid than in a D+/B- problem. A third series of experiments (Experiments 6-9) was designed to test the more general assumption that the effectiveness of nonreinforcement increases with the excitatory value of the context; response to B was found to be no different after A+/B+/C- training followed by A+/AB- training than after A+/B+/C- training followed by A+/CB- training. The results are compatible with the view that the role of nonreinforcement in honeybees is not to generate inhibition, but only to reduce excitation in a manner independent of the excitatory value of the context.     

Long delay learning in the T-maze

Rats were trained to go to one side of a T-maze with delays of reward lasting 1, 20, or 60 min in Expt 1 and 1 or 60 min in Expt 2. Mediation by secondary reward was prevented by administering the same delay treatment regardless of whether the response was correct or incorrect: after a response, the rat was removed from the choice alley and placed in its home cage to spend the delay. Feedback for the response was given in the startbox after the delay interval ended. The rats learned and there were no significant differences in performance among groups trained with different delays. These results had been expected on the basis of Revusky's (1971) hypothesis that removal of the rat from the learning situation to spend the delay elsewhere facilitates long delay learning by reducing associative interference. In Expt 3, this notion was tested explicitly by varying the amount of a 2-min delay to be spent in the experimental situation. Different groups of rats were left in the choice alley after the response for 0, 15, or 60 sec; then the rats were removed to spend the remainder of the 2-min delay in the home cage As predicted, the level of performance decreased as the length of time in the choice alley was increased.     

A multiple-observations model for response latency and the latencies of correct and incorrect responses in recognition memory

A model for response latency in recognition memory is described which is a strength model incorporating the notion of multiple observations and with the additional assumptions that the variance of the strength distributions increase with set size and that the observer attempts to keep his error rate at a constant level over set size. It is shown that the model can, without recourse to particular parameter values, predict a near linear RT set-size function and, since it is a (TSD) model in its decision aspects, can account for errors and hence error latencies in the recognition task. After the model is described, two experiments are performed which test the prediction that correct mean latency is generally shorter than incorrect mean latency. The prediction is confirmed and this feature is discussed in general, the model being compared with that of Juola, Fischler, Wood, and Atkinson (1971) in this respect. Some possible modifications to the latter model are also considered.     

The latencies of correct and incorrect responses in discrimination and detection tasks: Their interpretation in terms of a model based on simple counting

A model for two-choice discrimination based on a process of simple counting is described, and two experiments are performed to test the predictions of the model concerning the graph of latency as a function of response proportion. Two main forms of this graph are identified and predicted to arise in different circumstances. The experimental results support the model, and its possible extension to other psychophysical situations, especially signal detection, are then discussed. It is compared with a model derived directly from the detection situation, and the usefulness of testing these models is pointed out.     

The initial effect of noise on a simple vibrotactile learning task

In two experiments the effect of loud noise on a simple vibrotactile learning task was studied. After learning the task to criterion, 10 male and 10 female Ss received two pairs of test trials, one without noise, and one in continuous noise (a 1,000 cps pure tone at 90 dB SPL). An additional 10 male and 10 female Ss learned the same task and also received the same two pairs of test trials, but instead of receiving continuous noise for the second condition, they received an intermittent noise (random numbers presented at 2 sec intervals at 95 dB SPL). In the first experiment noise had a significant effect on the performance of the 20-subject group and also on the females in the group. Noise did not significantly affect the performance of males. In the second experiment noise had no significant effect on either males or females.     

An assessment of response, direction and place learning by rats in a water T-maze

Behavioral data suggest that distinguishable orientations may be necessary for place learning even when distal cues define different start points in the room and a unique goal location. We examined whether changes in orientation are also important in place learning and navigation in a water T-maze. In Experiment 1, rats were trained to locate a hidden platform and given a no-platform probe trial after 16 and 64 trials with the maze moved to a new position. Direction and response strategies were more prevalent than a place strategy. In Experiment 2, acquisition of place, response and direction strategies was assessed in a water T-maze that was moved between two locations during training. Rats were impaired on the place task when the maze was translated (moved to the L or R) but were successful when the maze was rotated across trials. These data are consistent with findings from appetitive tasks.     

Spatial learning in a T-maze by the crayfish Orconectes rusticus

The T-maze has commonly been used to investigate the mechanisms underlying spatial learning in vertebrates and has yielded much information about how animals use response and place cues to orient toward a goal. We designed a T-maze to study the spatial learning abilities of crayfish (Orconectes rusticus), using tactile stimuli as a place cue and escape from warm water for reinforcement. An initial experiment found that most animals did not display a side-turning bias when first placed in the maze, and hence animals were randomly assigned to escape from the left or the right arm, one of which contained a smooth floor and the other a rough floor. We found that, over repeated trials, the latency to escape and the number of turns made prior to escaping significantly decreased indicating that crayfish learned to escape from the maze more rapidly and efficiently. Learning occurred over the course of six trials on a single day, and over 5 days of testing, providing evidence for spatial memory lasting 24 hr. In probe trials, in which experienced animals started the maze in an arm opposite to that used during training trials, crayfish did not display a preference for either response-based learning or place-based learning. Instead they engaged in renewed exploration of the entire maze. These findings suggest that, in addition to remembering the location of the exit, crayfish also remembered the overall configuration of the maze.     

Blocking the incorrect alley in a two-drive learning situation

This experiment was designed to test the effect of blocking the path to an irrelevant reward on the subject's later performance when motivated for that reward, with a view to clarifying a well-known problem-situation.

An experimental group of 17 hooded rats was run in a two-choice maze, with food in one goal-box and water in the other, being motivated alternately for one or the other. The wrong goal-box was always blocked. Their performance on the first trial of the daily series was significantly poorer than that of a control group of 18 hooded rats, for which both boxes were always open. This difference persisted when, in a second period of training, the rhythm of motivation was altered for both groups.

It is concluded that blocking an irrelevant reward can have a disturbing effect and that this may be relevant to the problem-situation. It is also shown that such a result is to be predicted from Deutsch's (1953, 1956) theory.     

Integration and representation in rats' serial pattern learning in the T-maze

Rats were exposed to three-trial series consisting of reinforced (R) trials and one nonreinforced (N) trial in a fixed order, RRN and RNR (Experiments 1 and 2) or NRR and RRN (Experiment 3), on extended visually distinct runways in a T-maze. When initially presented with the same sequence on each series in a session (separate presentations) with the same runway on all trials within a series (Experiments 1 and 3), all the rats developed slower running speeds on N than on R trials. When a runway was sometimes changed between the first and next two trials during separate presentations training (Experiment 2) or both sequences were later intermixed within each session in each experiment, only rats exposed to each sequence on a specific runway maintained these serial running patterns. Rats displayed serial running patterns on a test RNN sequence similar to that on the RNR sequence (Experiment 2), as would be predicted by an intertrial association model of serial pattern learning (Capaldi & Molina, 1979), but responded on test RRR and NRN sequences (Experiment 3) as would be predicted by an ordinal-trial-tag/intratrial association model (Burns, Wiley, & Payne, 1986). Results from test series of free-choice trials in Experiments 1 and 2 failed to support a prediction of the intratrial association model that these rats would integrate RRN and RNR sequences. Rather than always selecting a baited runway on both the second and the third free-choice trials, the rats only selected a baited runway on the third trial on the basis of their choice on the second trial, as would be predicted by the intertrial association model. Only after experiencing all possible outcome sequences during forced-choice training in Experiment 3 did these rats predominantly select a baited runway on every free-choice trial.     

"None of the above" as a correct and incorrect alternative on a multiple-choice test: implications for the testing effect

Both positive and negative testing effects have been demonstrated with a variety of materials and paradigms (Roediger & Karpicke, 2006b). The present series of experiments replicate and extend the research of Roediger and Marsh (2005) with the addition of a "none-of-the-above" response option. Participants (n=32 in both experiments) read a set of passages, took an initial multiple-choice test, completed a filler task, and then completed a final cued-recall test (Experiment 1) or multiple-choice test (Experiment 2). Questions were manipulated on the initial multiple-choice test by adding a "none-of-the-above" response alternative (choice "E") that was incorrect ("E" Incorrect) or correct ("E" Correct). The results from both experiments demonstrated that the positive testing effect was negated when the "none-of-the-above" alternative was the correct response on the initial multiple-choice test, but was still present when the "none-of-the-above" alternative was an incorrect response.     

Test for effects of visual and position cues on T-maze learning in toads

This research was concerned with the effects of different classes of cues on the ability of toads (Bufo marinus) to learn an escape task, discrimination learning, in a T-maze. The cues were either a black or white brightness cue, a right or left position cue, or combinations of brightness and position cues. The toads were given a .6-A shock until they made the correct response. Results suggested that toads are capable of learning a discrimination task based on either a position or brightness cue. However, the rate of learning was influenced by strong aversion to the white arm when escaping from an aversive stimulus. No particular preference for either brightness or position cues was found independent of this aversion.     

Type 2 tasks in the theory of signal detectability: Discrimination between correct and incorrect decisions

It has been known for over 40 years that there are two fundamentally different kinds of detection tasks in the theory of signal detectability. The Type 1 task is to distinguish between events defined independently of the observer; the Type 2 task is to distinguish between one’s own correct and incorrect decisions about those Type 1 events. For the Type 1 task, the behavior of the detector can be summarized by the traditional receiver operating characteristic (ROC) curve. This curve can be compared with a theoretical ROC curve, which can be generated from overlapping probability functions conditional on the Type 1 events on an appropriate decision axis. We show how to derive the probability functions underlying Type 2 decisions from those for the Type 1 task. ROC curves and the usual measures of performance are readily obtained from those Type 2 functions, and some relationships among various Type 1 and Type 2 performance measures are presented. We discuss the relationshiPbetween Type 1 and Type 2 confidence ratings and caution against the practice of presenting transformed Type 2 ratings as empirical Type 1 ratings.