LA RETROALIMENTACIÓN NEGATIVA COMO MECANISMO A LA BASE DEL CAMBIO DE PREPARACIÓN MENTAL AL ALTERNAR ENTRE DOS TAREAS DE MANERA REGULAR Antonio González Hernández DEPARTAMENTO DE PSICOLOGÍA EXPERIMENTAL Y FISIOLOGÍA DEL COMPORTAMIENTO UNIVERSIDAD DE GRANADA Director: Dr. Emilio Gómez Milán

INDEX INTRODUCTION & HYPOTHESIS. –What is residual switch cost and how can we measure it? THE STIMULUS AS THE KEY. –Experiments 1 & 2. –Experiments 3 & 4. THE RESPONSE AS THE KEY. –Experiments 5, 6 & 7. CONCLUSIONS.

Introduction What is switch cost? –Transient impairment in performance (decrease in accuracy or increased RT). –Jersild (1927)- shift loss. –Spector and Biederman (1976). –Allport, Styles & Hsieh (1994)- task set inertia. –Indexes the duration of a control process that accomplishes task-set reconfiguration. –Rogers & Monsell (1995)- Two components.

Two components in task switching Non-residual component. –Can be eliminated by an active (endogenous) process of preparation. Residual component. –Can not be eliminated by an anticipation process. –Disappears after first repetition trial (under predictable conditions). –An exogenous reconfiguration process makes it disappear. –Represents a cognitive limitation.

Hypothesis Mental inertia (Allport et al, 1994). –Pro-active interference from a recently adopted task-set. –Cost asymmetry: larger cost when one switches from a non- dominant task to a dominant one. Non-dominant tasks result in a stronger set. Micropractice (Meiran, 1996). –Retroactive adjustment. –Gradual decrease not detected in R & M (1995).- predictable switch causes preparation for the next task, which slows the response on repetition trials. Stimulus cued completion hypothesis.

The stimulus cued completion hypothesis (Rogers & Monsell, 1995) Residual cost is associated to the appearance of a stimulus related to the new task. The appearance of the target would trigger the exogenous reconfiguration process.

How can we measure residual cost? –Predictable conditions Task switched every three trials. Fixation point was informative about the following task Long RSI (1200 ms.). –The tasks: Letter task: is the letter a vowel or a consonant? Number task: is the number odd or even?

@ or # (1200 ms)

1A B4 C2 E3 (500 ms)

RESPONSE (b or n in the keyboard) (2500 ms) (Sound feedback for errors and no response)

Results under predictable conditions There is a switch cost. Cost disappears with first repetition trials.

Research goals To verify the disappearance of residual cost after the first repetition trial. To determine the real nature of this residual component. –Is the stimulus the key to complete reconfiguration? –Is it the response? –Are both? For these goals we have created new conditions: –Stimulus without response. –Response without stimulus.

INDEX INTRODUCTION & HYPOTHESIS. –What is residual switch cost and how can we measure it? THE STIMULUS AS THE KEY. –Experiments 1 & 2. –Experiments 3 & 4. THE RESPONSE AS THE KEY. –Experiments 5, 6 & 7. CONCLUSIONS.

Experiment 1- Goals To verify the role played by the stimulus in mental set reconfiguration.

Experiment 1- Design Participants: Twelve undergraduates. Variables: –Condition: Go or No-Go (go-signal in switch trials). Go-signal before the stimulus (50%). –Congruency: congruent and incongruent trials. –Task: letter task and number task. –Repetition: switch trials; first repetition trials; second repetition trials. Dependent Variables: RT and accuracy.

SWITCH TRIALS FIRST REPETITION TRIALS SECOND REPETITION TRIALS NO-GO CONDITION NO RESPONSERESPONSE GO CONDITION RESPONSE Experiment 1- Design

Experiment 1- Hypothesis If attention to the stimulus completes reconfiguration no cost would appear in no-go condition ( ) If the stimulus is not the key, we will observe a cost displacement (---).

Experiment 1- Results There is a cost displacement from switch trials to first repetition trial.

Experiment 1- Conclusions With the go-condition we replicate results using predictable sequences. –Cost disappears with first repetition trials. With the no-go condition we observe that paying attention to the stimulus does not eliminate cost. –We can observe cost even with a more than five seconds of foreknowledge period.

Experiment 2- Goals To ensure attention in no-go condition. To verify the role played by the stimulus in mental set reconfiguration. –Differences with experiment 1: The go-signal appears 500 ms. after the target. The go-signal was manipulated on a trial by trial basis.

Experiment 2- Design Participants: Ten undergraduates. Variables: –Condition: Go or No-Go (Go-signal in switch trials). The go-signal appeared 500 ms after the target (50%). –Congruency: congruent and incongruent trials. –Task: letter task and number task. –Repetition: switch trials; first repetition trials; second repetition trials. Dependent Variables: RT and accuracy.

SWITCH TRIALS FIRST REPETITION TRIALS SECOND REPETITION TRIALS NO-GO CONDITION NO RESPONSERESPONSE GO CONDITION RESPONSE Experiment 2- Design

Experiment 2- Hypothesis In this case we ensure the attention to the stimulus. If this is sufficient, no cost will be observed in no-go condition ( ). If it is not, a cost displacement will appear (---).

Experiment 2- Results Results are similar to those found in experiment 1. We found again a cost displacement. Attention to the stimulus and response programming are not enough to complete reconfiguration.

Experiment 2- Conclusions The general improvement in RT and accuracy indexes to the response preparation. There is a cost displacement from switch trials to first repetition trials. In the Go Condition, we observed a similar pattern of results to that found in Go Condition of experiment 1.

Experiment 3- Goals To eliminate sequential effects due to the go-nogo manipulation. To verify the role played by the stimulus in mental set reconfiguration. –Differences with the previous experiments: There were also no-go repetition trials. To verify Schuch & Koch hypothesis: –Predicts residual cost if response selection occurs.

Experiment 3- Design Participants: Ten undergraduates. Variables: –Condition: Go signal in trial n-1: Go or No-Go. In this experiment the go-signal No could appear in every trial. 50%. –Congruency: congruent and incongruent trials. –Task: letter task and number task. –Repetition: switch trials; first repetition trials; second repetition trials. Dependent Variables: RT and accuracy.

SWITCH TRIALS FIRST REPETITION TRIALS SECOND REPETITION TRIALS NO-GO CONDITION NO RESPONSE IN PREVIOUS TRIAL GO CONDITION RESPONSE IN PREVIOUS TRIAL Experiment 3- Design

Experiment 3- Hypothesis There are also no-go repetition trials in order to avoid sequential effects produced by the go-signal manipulation. Following Schuch & Koch hypothesis there must not be cost in No- Go condition.

Experiment 3- Results In the Go-condition the pattern of results was consistent with the normal residual cost found under predictable conditions. In the No-Go condition there seems to be no cost, as reported Schuch and Koch (2003).

Experiment 3- Conclusions The slower RTs found for No-Go condition could be due to sequential effects. These results could be explained as a no cost or as a no repetition benefit.

Experiment 4- Goals To ensure response preparation increasing the go-signals validity (80%). To verify the role played by the stimulus in mental set reconfiguration. To verify Schuch & Kochs hypothesis. Differences with experiment 3: –There is a higher go-signals validity.

Experiment 4- Design Participants: Eight undergraduates. Variables: –Condition: Go signal in trial n-1: Go or No-Go. In this experiment the go-signal No could appear in every trial. 80%. –Congruency: congruent and incongruent trials. –Task: letter task and number task. –Repetition: switch trials; first repetition trials; second repetition trials. Dependent Variables: RT and accuracy.

SWITCH TRIALS FIRST REPETITION TRIALS SECOND REPETITION TRIALS NO-GO CONDITION NO RESPONSE IN PREVIOUS TRIAL GO CONDITION RESPONSE IN PREVIOUS TRIAL Experiment 4- Design

Experiment 4- Hypothesis The go-signals validity is higher (80%) so expected response selection. Following Schuch & Koch hypothesis, there will be residual cost in No-go condition.

Experiment 4- Results Again we replicated residual cost in the Go- condition. In the No-Go condition there is a cost displacement from switch trials to first repetition trials.

Experiment 4- Conclusions. The Go-Signal validity is important. Residual cost was still apparent in the first repetition trials in No-Go condition. Response selection seems to be the key factor to produce the residual cost: (no residual cost in No-Go condition Experiment 3 (Go-Signal validity=50%) vs significant residual cost in No-Go condition Experiment 4 (Go-Signal=80%).

It seems clear that what triggers exogenous reconfiguration process is not stimulus- related. Response selection seems to be the key factor to produce residual cost. Conclusions from experiments 1-4

INDEX INTRODUCTION & HYPOTHESIS. –What is residual switch cost and how can we measure it? THE STIMULUS AS THE KEY. –Experiments 1 & 2. –Experiments 3 & 4. THE RESPONSE AS THE KEY. –Experiments 5, 6 & 7. CONCLUSIONS.

Experiment 5- Goals To verify the responses role in mental set reconfiguration. For this aim we created a new condition where a response was executed in the absence of the target.

Experiment 5- Design Participants: twelve undergraduates. Variables: –Condition: Response in ITI (space bar); No response in ITI. –Congruency: congruent and incongruent trials. –Task: letter task and number task. –Repetition: switch trials; first repetition trials; second repetition trials. Dependent Variables: RT and accuracy.

SWITCH TRIALS FIRST REPETITION TRIALS SECOND REPETITION TRIALS NO RESPONSE CONDITION NO RESPONSE IN PREVIOUS ITI NO RESPONSE IN PREVIOUS ITI1 NO RESPONSE IN PREVIOUS ITI RESPONSE CONDITION RESPONSE IN PREVIOUS ITI Experiment 5- Design

Experiment 5- Hypothesis If any response (in the absence of the target) completes the reconfiguration, no cost must appear in response in ITI condition.

Experiment 5- Results Again we replicate residual component in No response condition. No effect of response in ITI was observed.

Experiment 5- Conclusions Any single unrelated response does not trigger the mechanism of mental set reconfiguration to switch from a task to a new one without cost. With the results obtained we can not conclude that motor responses are not important to complete the reconfiguration. In the next experiment we will observe what happens with residual cost if the response to execute during the ITI is a related one.

Experiment 6- Goals To verify the responses role in mental set reconfiguration. For achieve this aim we modified the response to execute during ITI.

Experiment 6- Design Participants: twelve undergraduates. Variables: –Condition: Response in ITI (b key or the n key); No response in ITI. –Congruency: congruent and incongruent trials. –Task: letter task and number task. –Repetition: switch trials; first repetition trials; second repetition trials. Dependent Variables: RT and accuracy.

SWITCH TRIALS FIRST REPETITION TRIALS SECOND REPETITION TRIALS NO RESPONSE CONDITION NO RESPONSE IN PREVIOUS ITI NO RESPONSE IN PREVIOUS ITI1 NO RESPONSE IN PREVIOUS ITI RESPONSE CONDITION RESPONSE IN PREVIOUS ITI Experiment 6- Design

Experiment 6- Hypothesis If this response (in the absence of the target) completes the reconfiguration, no cost must appear in response in ITI condition.

Experiment 6- Results Again we replicate residual cost in No response condition. Response in ITI seems to eliminate residual cost.

Experiment 6- Conclusions These intermediate associated responses eliminate the residual cost: participants execution in switch trials is as good as in repetition trials. The execution in all the trials in the response in ITI condition behave like repetition trials. In the next experiment we will see what happens with a choice extra task and unrelated responses.

Experiment 7- Goals To verify the responses role in mental set reconfiguration. For achieve this aim, in this experiment the response was not related with the alternating tasks.

Experiment 7- Design Participants: twelve undergraduates. Variables: –Condition: Response in ITI (the R key or the O key); No response in ITI. –Congruency: congruent and incongruent trials. –Task: letter task and number task. –Repetition: switch trials; first repetition trials; second repetition trials. Dependent Variables: RT and accuracy.

SWITCH TRIALS FIRST REPETITION TRIALS SECOND REPETITION TRIALS NO RESPONSE CONDITION NO RESPONSE IN PREVIOUS ITI NO RESPONSE IN PREVIOUS ITI1 NO RESPONSE IN PREVIOUS ITI RESPONSE CONDITION RESPONSE IN PREVIOUS ITI Experiment 7- Design

Experiment 7- Hypothesis If this choice response (in the absence of the target) completes the reconfiguration, no cost must appear in response in ITI condition.

Experiment 7- Results Again we replicate residual component in No response in ITI condition. Response in ITI seems to eliminate residual cost.

Experiment 7- Conclusions. These intermediate non-associated responses eliminate the residual cost: participants execution in switch trials is as good (or even better) as in repetition trials. An irrelevant interpolated task can be used to abolish residual cost. Therefore it seems that it is a choice task what triggers the reconfiguration mechanism (even in the absence of target).

INDEX INTRODUCTION & HYPOTHESIS. –What is residual switch cost and how can we measure it? THE STIMULUS AS THE KEY. –Experiments 1 & 2. –Experiments 3 & 4. THE RESPONSE AS THE KEY. –Experiments 5, 6 & 7. CONCLUSIONS.

General Conclusions-I The residual switch cost seems to be a very robust effect with predictable sequences; it seems to be a real cognitive limitation (we have replicated it in all our experiments). It seems clear that what triggers exogenous reconfiguration process is not stimulus- related. Response selection seems to be the key factor to produce residual cost.

General Conclusions-II The execution of a choice response (even in the absence of the target) seems to complete the mental set reconfiguration process, and consequently, eliminate residual cost. This response must not be necessarily related with the task. A choice response, where some kind of uncertainty is elicited, completes the reconfiguration.

General Conclusions-III Residual cost shows a cognitive limitation that forces us to make a mistake (or to prevent to make a mistake) before our mental set is reconfigured. Our results are against the stimulus cued completion hypothesis and in favor of a cognitive reset button in the brain (activation of S-R decision rules and response execution). There seems to be a negative feed-back mechanism that completes the mental reconfiguration necessary to execute the new task in a suitable way.

General Conclusions-IV Only a retroactive adjustment after a response execution makes residual cost disappear. Our system is able to activate this negative feed-back mechanism by means of the execution of a choice response even in the absence of the target.

Muchas gracias por su atención Thank you Antonio González- LA RETROALIMENTACIÓN NEGATIVA COMO MECANISMO A LA BASE DEL CAMBIO DE PREPARACIÓN MENTAL AL ALTERNAR ENTRE DOS TAREAS DE MANERA REGULAR