The Differential Impact of a Response's Effectiveness and its Monetary Value on Response-Selection

Abstract

While known reinforcers of behavior are outcomes that are valuable to the organism, recent research has demonstrated that the mere occurrence of an own-response effect can also reinforce responding. In this paper we begin investigating whether these two types of reinforcement occur via the same mechanism. To this end, we modified two different tasks, previously established to capture the influence of a response's effectiveness on the speed of motor-responses (indexed here by participants' reaction times). Specifically, in six experiments we manipulated both a response's 'pure' effectiveness and its outcome value (e.g., substantial versus negligible monetary reward) and measured the influence of both on the speed of responding. The findings strongly suggest that post action selection, responding is influenced only by pure effectiveness, as assessed by the motor system; thus, at these stages responding is not sensitive to abstract representations of the value of a response (e.g., monetary value). We discuss the benefit of distinguishing between these two necessary aspects of adaptive behavior namely, fine-tuning of motor-control and striving for desired outcomes. Finally, we embed the findings in the recently proposed Control-based response selection (CBRS) framework and elaborate on its potential for understanding motor-learning processes in developing infants.

Figure 1

An illustration of a trial in the Substantial Monetary Gain with pure response-effectiveness feedback condition. Participants are instructed to press a spatially and color-coded key on a standard keyboard when they first see the descending cue (left box). Immediately after an appropriate response, the circle cue changes to a one NIS coin for 200 ms (middle box) and disappeared until the end of the trial (right box). The 1 NIS coin image depicts a unit of currency issued by the Bank of Israel. This design is copyrighted by the Bank of Israel.

Figure 2

Experiments 1a-3: The impact of monetary value on the speed of response-selection. (a): Experiment 1a. (b): Experiment 1b. (c): Experiment 2a. (d): Experiment 2b. (e): Experiment 3. (f): all five experiments combined. Error bars depict 95% confidence intervals.

Figure 3

Experiment 4 - The impact of pure effectiveness-feedback and monetary value on the speed of response-selection. (a) presents the difference in mean RT between monetary values when pure effectiveness-feedback is not provided. Error bars depict 95% confidence intervals. (b) presents the difference in mean RT between monetary values when pure effectiveness-feedback is provided. Error bars depict 95% confidence intervals. (c) present differences in RT for each participant in the Substantial Monetary Gain condition, in blocks with and without pure effectiveness-feedback. (d) presents differences in RT for each participant in the Negligible Monetary Gain condition, in blocks with and without pure effectiveness-feedback.