Libetus Interruptions

Ullsperger, Bylsma, and Botvinick (2005) investigated whether the findings of Mayr, Awh, and Laurey (2003) can be replicated and how much they can be shown across different task performances. Their specific study was motivated by a prior experiment where Gratton, Coles, and Donchin (1992) found that after an incompatible type trial reaction times were reduced and target processing occurred more frequently than flanker processing on the next trial. Botvinick, Braver, Barch, Carter, and Cohen (2001) believed that this follows the conflict monitoring hypothesis where incompatible trials involve a conflict with the response leading to greater top-down information processing (Botvinick, Nystrom, Fissell, Carter, & Cohen, 1999). However, Mayr et. al (2003) argued that the congruency sequence effect found by Gratton et al. (1992) was due to repetition priming because of stimulus repeats in a flanker task. This may have led to a faster reaction time with repeated trials. Mayr et al. (2003) used two experiments to present evidence for their argument. Both experiments failed to show the effect found by Gratton et al. (1992) when target and stimulus items did not repeat from trial to trial.

After this activity, they were asked to do a “lexical decision task” (a standard approach for measuring unconscious responses) in which they were shown a series of words and nonwords in random order and had to press “C” if it was a real word or “N” if not. Half of the real words were related to autonomy (e.g., freedom, choice) and half were neutral (e.g., whisper, hammer). The key focus of the study was on how long it took people to press the button *(“response latency”) for each kind of real word, averaged over the many words of each type. The table below

Suppose another experiment had participants say the word “now” as soon as they detected the green circle, and that the response times were between 100 and 200 milliseconds. What would you conclude about the cognitive tasks involved in these two versions of simple detection?

Following classical conditioning the data show a decrease in variability and in the latency between stimulus presentation and the response. There is also a change in trend from increasing to no trend.

The integration of predictive signals and sensory signals from an actual movement allows for accurate motor execution. Judgment of temporal order refers to certain arrangements of events in time (Keetels et al. 2012). The research paper “Predicting Future Sensorimotor States Influences Current Temporal Decision Making” (Hermosillo et al. 2011), describes an experiment where participants had to complete a temporal order judgment task (TOJ) where they were told to follow specific instructions on limb movement such as crossing or uncrossing arms. At the same time, they conducted vibrotactile stimulation and measured how it affected their decision-making. The main focus and finding of the paper demonstrated that planning limb movements (crossing/uncrossing arms) have some influence on judgments of temporal order, which suggests that the human brain is able to predict sensory consequences

The reaction timer from Maths Is Fun (2014) is specific to three decimal places. The accuracy of the chosen source reduces the risk of statistical measures being slightly greater or less than they would be if only one or two decimal places were provided. Unlike other reaction timers that are available online, this particular source requires the subject to complete five trials before the mean is calculated. Undertaking multiple trials will be vital to this investigation because if the subject was to anticipate the event or have one delayed response, the trials that follow would reveal such errors, therefore increasing the reliability of the results.

Neurons' firing while observing an action can be helpful in planning one's actions, as the consequences of those actions can also be observed.

The reaction time (RT) of students was measured in the experiment to determine whether light or sound stimulus initiates a quicker response time. The question of whether or not RT was related to movement time (MT) was also challenged. Each student performed two test in random order; one testing the reaction time of a red light stimulus, or visual reaction time (VRT); and the other testing the reaction time of a “beeping” sound stimulus, or auditory reaction time (ART). The student completed the VRT trial by simply receiving the stimulus and pressing a button. The student placing and holding their hand on a button starts the ART trial. Once the student receives the stimulus (beep) they press the adjacent button as fast as they can. The ART trial does not only include the data of the RT, but also the data from the MT. Having previous knowledge that light travels faster than sound; one can predict that VRT is faster than ART. The prediction that MT is independent upon RT can be made with the thought that there are so many opposing variables that could affect the MT of an individual unrelated RT such as old age

In Benjamin Libet’s free will experiment in the early 1980’s seemed to prove that that free will was an illusion. He conducted the experiment by creating a special clock, known as the “oscilloscope clock”, which was sped up to be 25 times faster than a normal clock in order to find out when the subject first had the urge to act. The subject would stare at he center of the clock and would mentally record when he/she had the will to flick their wrist or move a finger. These times would then be recorded after the experiment was over. Libet’s research question was, “when does the conscious wish or intention (to perform the act) appear?” What he found was that the readiness potential, or RP, began 550 msec. before the actual act. The way I interpreted

The experiment took place in an isolated, dim-light and sound-attenuated room with video control. During task performances, participants were seated in front of a monitor at a viewing distance of approximately 40-60 cm. The stimuli were presented with Presentation (neurobehavioral systems), a stimulus delivery and experiment control program. Participants could give a response with joysticks that were placed at both arms of the chair. The research assistant remained in the same room as the participants, however, interaction took only place during the breaks. The length of the experiment varied due to the tracking paradigm (see 2.3.3 Experimental design and task) and length of breaks.

The late P3b effect suggests that the brain is able to register and learn sequences occurring across relatively long time window, and then detect when those are violated. This neural property is most likely dependent on conscious awareness, taken that the neural signature of violation detection occurred ~300 ms after the presentation of a violating tone, which is also the latency at which conscious global ignition typically occurs (Dehaene et al., 2014, 2006; Dehaene & Changeaux, 2011). Modeling work by Garrido, Kilner, Kiebel, & Friston (2007) supported the idea that this late electrophysiological effect to violations critically depends on backward connections and recurrent interactions between brain areas. Garrido et al. (2007) inspected

Although the specific properties and consequences of this nonlinear association must be addressed by future studies, our results shed some light on the connection between frontal motor activity and the action

Line 149-154: This is a bit confusing (perhaps just to me): "... an action is declared susceptible to SEM". Is the action susceptible to the startle-evoked movement? I would revise this throughout the whole paper.

Functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) studies have shown that people’s brains exhibit activity up to seven seconds prior to a conscious decision being made to act, implying that the forces causing the action are entirely unconscious (Soon, Brass, Heinz & Haynes, 2008; Lisbet, B. 1985). It is asserted that, at the most, people act as interpreters, who provide post factum rationale for whatever it was the brain had them think, feel or do (Gazzanigna, 2011).

Wilson describes the first claim; “While a cognitive process is being carried out, perceptual information continues to come in that affects processing, and motor activity is executed