On the value of advanced information about delayed rewards.

In a variety of laboratory preparations, several animal species prefer signaled over unsignaled outcomes. Here we examine whether pigeons prefer options that signal the delay to reward over options that do not and how this preference changes with the ratio of the delays. We offered pigeons repeated choices between two alternatives leading to a short or a long delay to reward.

Time, uncertainty, and suboptimal choice.

Under certain conditions, pigeons prefer information about whether food will be forthcoming at the end of an interval to a higher chance of obtaining the food. In the typical protocol, choosing one option (Informative) is followed by one of two 10-s long terminal-link stimuli: S always ending in food or S never ending in food, with S occurring only 20% of the trials. The other option (Non-informative) is also followed by one of two 10-s long terminal-link stimuli: S or S, both ending in food 50% of the trials.

Giving time a chance in the midsession reversal task.

The midsession reversal task involves a simultaneous discrimination between stimuli S1 and S2. Choice of S1 but not S2 is reinforced during the first 40 trials, and choice of S2 but not S1 is reinforced during the last 40 trials. Trials are separated by a constant intertrial interval (ITI).

Midsession reversal task with starlings: A quantitative test of the timing hypothesis.

In the Mid-Session Reversal task (MSR), an animal chooses between two options, S1 and S2. Rewards follow S1 but not S2 from trials 1-40, and S2 but not S1 from trials 41-80. With pigeons, the psychometric function relating S1 choice proportion to trial number starts close to 1 and ends close to 0, with indifference (PSE) close to trial 40.

Time to contrast models of timing: The structure of temporal memory.

In the study of animal timing over the last 100 years, we identify three different periods, each characterized by a distinct activity. In the first period, researchers brought timing into the laboratory and explored its multiple expressions empirically. In the second period, the growing body of empirical findings inspired researchers to develop a plethora of timing models that vary in theoretical orientation, scope, depth, and quantitative explicitness.

Constantly timing, but not always controlled by time: Evidence from the midsession reversal task.

We used a midsession reversal task to investigate how temporal and situational cues may combine to determine choice in frequently changing environments. Pigeons learned a simultaneous discrimination with 2 stimuli: S1 and S2. Choices of S1 were reinforced only during the first trials, and choices of S2 were reinforced only during the last trials of the session, that is, the reinforcement contingencies reversed once during the session.

Base rates bias performance in a temporal bisection task.

We investigated how base rates affect temporal discrimination. In a temporal bisection task, pigeons learned to choose one key after a short sample and another key after a long sample. When presented with a range of intermediate samples they produced a psychometric function characterized by a bias and a scale parameter.

Correction to: Rules of Conduct for Behavior Analysts in the Presence of Hypothetical Constructs: A Commentary on Eckard and Lattal (2020).

[This corrects the article DOI: 10.1007/s40614-020-00272-w.].

Testing the Δ-∑ hypothesis in the suboptimal choice task: Same delta with different probabilities of reinforcement.

In a concurrent-chain procedure, pigeons choose between 2 initial-link stimuli; one is followed by terminal link stimuli that signal reliably whether food will be delivered after a delay; the other is followed by terminal link stimuli that do not signal whether food will be delivered after the delay. Pigeons prefer the former alternative even when it yields a lower overall probability of food. Recently, we proposed the Delta-Sigma (∆-∑) hypothesis to explain the effect: Preference depends on the difference (∆) between the reinforcement probabilities associated with the terminal link stimuli, and the overall probability of reinforcement (∑) associated with the alternative.

Rules of Conduct for Behavior Analysts in the Presence of Hypothetical Constructs: A Commentary on Eckard and Lattal (2020).

Eckard and Lattal (2020) summarized the behavioristic view of hypothetical constructs and theories, and then, in a novel and timely manner, applied this view to a critique of internal clock models of temporal control. In our three-part commentary, we aim to contribute to the authors' discussion by first expanding upon their view of the positive contributions afforded by constructs and theories. We then refine and question their view of the perils of reifying constructs and assigning them causal properties.

Step changes in the intertrial interval in the midsession reversal task: Predicting pigeons' performance with the learning-to-time model.

Our goal was to assess the role of timing in pigeons' performance in the midsession reversal task. In discrete-trial sessions, pigeons learned to discriminate between 2 stimuli, S1 and S2. Choices of S1 were reinforced only in the first half of the session and choices of S2 were reinforced only in the second half.

The functional equivalence of two variants of the suboptimal choice task: choice proportion and response latency as measures of value.

In the suboptimal-choice task, birds systematically choose the leaner but informative option (suboptimal) over the richer but non-informative option (optimal). The task has two variations. In the standard task, the optimal option includes two terminal link stimuli.

Effects of differential probabilities of reinforcement on human timing.

We investigated how differential payoffs affect the temporal discrimination of humans. In a temporal bisection task, participants learned to make one response after a short sample and another after a long sample. When presented with a range of intermediate samples, the proportion of responses fitted well a Gaussian-like distribution function characterized by a location (bias), a scale (sensitivity) parameter, and two asymptote (discrimination) parameters.

The Δ-∑ hypothesis: How contrast and reinforcement rate combine to generate suboptimal choice.

When given a choice between two alternatives, each offering food after the same delay with different but signaled probabilities, pigeons often prefer the low probability alternative. This preference is surprising because pigeons fail to maximize the rate of food intake; they exhibit a suboptimal preference. We advance a new explanation, the Δ-∑ hypothesis, in which the difference in probability of reinforcement within terminal links (Δ) and the overall reinforcement probability rate of each alternative (∑) are the key variables responsible for such suboptimal preference.

Simple discrimination in stingless bees (Melipona quadrifasciata): Probing for select- and reject-stimulus control.

Simple and conditional discrimination training may produce various types of controlling relations. Responses may be controlled primarily by the positive stimulus (select-control relation) or by the negative stimulus (reject-control relation; the subject excludes the negative stimulus and chooses the positive). Bees learn to respond in simple and conditional discriminations.

Corrigendum: Effects of Nodal Distance on Conditioned Stimulus Valences Across Time.

[This corrects the article DOI: 10.3389/fpsyg.2019.

Effects of Nodal Distance on Conditioned Stimulus Valences Across Time.

A meaningless symbol that repeatedly co-occurs with emotionally salient faces (US) can transform into a valenced symbol (CS). US-to-CS valence transformations have been observed for CS that have been directly (US→CS0) and indirectly (US→CS0→CS1→CS2) linked with face US. The structure of a US→CS0→CS1→CS2 series may be conceptualized in terms of "nodal distance," where CS0, CS1, and CS2 are 0, 1, and 2 nodes from the US respectively.

The effect of reinforcement probability on time discrimination in the midsession reversal task.

We examined how biasing time perception affects choice in a midsession reversal task. Given a simultaneous discrimination between stimuli S1 and S2, with choices of S1 reinforced during the first, but not the second half of the trials, and choices of S2 reinforced during the second, but not the first half of the trials, pigeons show anticipation errors (premature choices of S2) and perseveration errors (belated choices of S1). This suggests that choice depends on timing processes, on predicting when the contingency reverses based on session duration.

Biasing performance through differential payoff in a temporal bisection task.

We investigated how differential payoffs affect temporal discrimination. In a temporal bisection task, pigeons learned to choose one key after a short sample and another key after a long sample. When presented with a range of intermediate samples they produced a Gaussian psychometric function characterized by a location (bias) parameter and a scale (sensitivity) parameter.

The evolution of the behavior systems framework and its connection to interbehavioral psychology.

The present article traces the development of Timberlake's behavior systems framework while noting connections between it and Kantor's interbehavioral psychology. Congruent with Timberlake's behavior systems approach, interbehaviorists assert that (a) behavior is best understood as part of a complex causal system instead of a simple linear model, (b) the study of learning and behavior analysis should consist of the study of multiple responses and the systematic observation of response forms, (c) learning involves the reorganization of a behavior system, (d) behavioral analyses should be more ecological in orientation, and (e) psychology would benefit from a set of methodologies and apparatuses broader than those normally used to study operant and Pavlovian conditioning. These connections may derive from two broad themes shared by the behavior systems framework and interbehavioral psychology: an appreciation for a systems view of behavior and the importance of ethological considerations.

Log versus linear timing in human temporal bisection: A signal detection theory study.

Using signal detection theory, we investigated whether human participants represent time linearly or logarithmically in a bisection task. Participants saw a stimulus 1.0 to 1.

A new variable interval schedule with constant hazard rate and finite time range.

We propose a new variable interval (VI) schedule that achieves constant probability of reinforcement in time while using a bounded range of intervals. By sampling each trial duration from a uniform distribution ranging from 0 to 2 T seconds, and then applying a reinforcement rule that depends linearly on trial duration, the schedule alternates reinforced and unreinforced trials, each less than 2 T seconds, while preserving a constant hazard function.

The paradoxical effect of low reward probabilities in suboptimal choice.

When offered a choice between 2 alternatives, animals sometimes prefer the option yielding less food. For instance, pigeons and starlings prefer an option that on 20% of the trials presents a stimulus always followed by food, and on the remaining 80% of the trials presents a stimulus never followed by food (the Informative Option), over an option that provides food on 50% of the trials regardless of the stimulus presented (the Noninformative Option). To explain this suboptimal behavior, it has been hypothesized that animals ignore (or do not engage with) the stimulus that is never followed by food in the Informative Option.

Ultimate explanations and suboptimal choice.

Researchers have unraveled multiple cases in which behavior deviates from rationality principles. We propose that such deviations are valuable tools to understand the adaptive significance of the underpinning mechanisms. To illustrate, we discuss in detail an experimental protocol in which animals systematically incur substantial foraging losses by preferring a lean but informative option over a rich but non-informative one.