Task 1

Question 1

Two key concepts underlie the cognitive approach:

Answer 1

1. Information processing depends on internal representations
2. These mental representations undergo transformations.

Question 2

The fact that RT vary (especially in the same category condition) shows

Answer 2

that we have representations of the physical, identity (a = A) and abstraction (category) of a stimuli

Question 3

Internal transformations

Answer 3

Our mental representations undergo transformations (i.e. memories about smells transform olfactory sensations into memories). The most common transformation is that of sensations being transformed into perceptions being transformed into actions. This can be altered through memories (i.e. when you’re scared of dogs you wont pet a dog that others would

Question 4

Word superiority effect

Answer 4

people are most accurate in identifying a target letter when the stimuli are words, which suggests that we do not need to identify all the letters of a word before we recognize the word.
etter and word
representations are activated in parallel which facilitates performance

Question 5

Mental chronometry

Answer 5

the study of the organization and timing of mental processes.

Question 6

the subtraction method

Answer 6

he constructed two tasks that differ only in a single component of processing, and measure reaction time in both tasks. Then subtract the reaction times; the outcome is the duration of that single component. The same simple subtraction forms the basis of modern functional brain imaging techniques (EEG, fMRI, …).

Question 7

Operationally defined, reaction time is the time interval between the onset of a stimulus and the overt response to that stimulus, in this case the button press. However theoretically…

Answer 7

Assumption: that the participant intends to be “as fast as possible without making errors”

We can therefore theoretically define RT as the minimum amount of time needed by the participant
to produce a correct response.

Question 8

Speed-accuracy tradeoff

Answer 8

more errors happen when the participant tries to be really fast, but most researchers prefer this over perfect performance, just to avoid the risk that the participant takes more time than actually needed

Question 9

why measure RT?

Answer 9

-reliabilty & orderliness (RT is interesting when there are sensitive differences between experimental conditions)
. - scale properties: there is a meaningful zero point=> can be interpreted easily (often measured variable is time)
-Rt is the only property of mental processes we can measure

Question 10

limitation of RT

Answer 10

• only simple tasks (rt with 100-200 ms)
  -rt can only reflect the end product of the process
  => we can only observe output and make guesses what happens in between

-Knowledge of processes involved in a task: In practice, we may not have prior knowledge about which exact kind of stage is added or removed when we change the task in some way

Question 11

donders substraction method

Answer 11

A: sensory time + motor time =201 ms
B: sensory time+discrimination time+ response selection time +motor time =284 ms
C: sensory time+ discrimination time + motor time =237 ms

subtracting B-C gives duration of response selection

subtracting C-A gives the duration of stimulus discrimination

Question 12

Donders task assumptions

Answer 12

seriality

pure insertion
=> critique because for example lower readiness to respond can also effect motor processes

knowledge of processes involved in task
=>In practice, we may not have prior knowledge about which exact kind of stage is added or removed when we change the task in some way

Question 13

Sternberg’s Memory Search Task

Answer 13

This task attempted to purely insert multiple processing steps.
On each trial, a set of letters is presented, and the participant is asked to memorize them. This set can contain from 1 to 6 letters. After the letters have disappeared, a single ‘probe’ stimulus is presented, and it is to be decided whether the probe letter is a member of the just memorized set. A “YES” or a “NO” response can then be given.

Question 14

overall findings of Sternbergs task

Answer 14

Mean RT appear to increase linearly with the number of items held in memory

The slope is similar for positive and negative responses, even though they require exhaustive searching of the entire set (whereas positive responses are self-terminating). This suggests that participants continue to search the set, even after they found a match (non-optimality).

The fact that the function is linear suggests that the time to scan each single item does not depend on the total size of the set (= orderliness of RT).

Question 15

additive factor method

propositions

Answer 15

• Serial / successive processing: information is processed serially and each stage performs some transformation on its input, producing some output that is passed on to the next stage (evidence: successive levels of the visual system)
• Constant output: manipulation to increase RT increases the duration of one or more processing stages but does not change the output of that stage. The output is therefore independent of the duration. If the output of some stage is constant, it can be seen that the next stage can then act as normal. Later processing stages cannot compensate for delays earlier on. An increased duration of some stage is simply propagated through all following stages to the final response.
• Total RT is the sum of the stage durations
• If two different manipulations affect two different stages, they will produce independent effects on total RT: the effects should be additive and not interact in statistical sense
• If 2 manipulations interact (modify each other) they must affect some stage in common
   Additivity of effects of two factors is consistent with the presence of two processing stages

AFM does not contain the assumption of pure insertion

Question 16

Simon effect

Answer 16

Responses are faster to stimuli presented at the same side as the response (‘corresponding’) than to stimuli presented opposite the response (‘noncorresponding’) ^

Question 17

speed accuracy trade off solutions

Answer 17

One is to sample a SAT curve, which would be very time-consuming. The second alternative is therefore preferred: Diffusion Models.

Question 18

Diffusion models regard

Answer 18

(1) the speed of information uptake, (2) the amount of information used to make a decision, (3) possible decision biases, and (4) the duration of non-decisional processes.

Question 19

The analysis of RT at two levels

outliers

Answer 19

Methods to deal with outliers are the following:
o Medians = robust measure of central tendency. It is relatively insensitive to outliers but only if number of observations if big enough and different across conditions. It deletes the upper and lower 50 % of the distribution. In the context of AFM, the use of the median is problematic
o Trimmed means = deletes a smaller proportion (fastest and slowest 10%) and takes the mean of the remaining ones
o C standard deviations = First compute a mean and standard deviation for each participant and condition, then delete RTs that deviate more than some number ‘C’ (often 2.5) of standard deviations from the mean. This is based on the assumption of normality of the data.
o Fixed criterion = Delete all RTs exceeding some value and compute the mean of the rest. The risk here is to delete more trials from one side of the distribution which could lead to a bias and a loss of statistical power.
o Doing nothing = this decision should be thought through and preferably an outlier analysis should be asses just to see if important effects depend on extreme values

Question 20

Outliers at level 2:

Answer 20

removing outliers at this stage is not wise because now, any effect can be made significant by removing participants that don’t show the effect

Question 21

SMULDERS – COMMENTARY ON BONIN-GUILLAUME et al.: AN ADDITIVE FACTOR ANALYSIS OF THE EFFECT OF DEPRESSION ON THE REACTION TIME OF OLD PATIENTS

results

Answer 21

• results indicate that depression interacts with foreperiod duration on RT and with stimulus–response compatibility on the error rate, that motor adjustment and response selection are functional targets of depression in the elderly (main effect of foreperiod duration)
• depression and stimulus intensity display additive effects on RT (depression spares the stage of stimulus processing) (main effect on stimulus intensity)
• interaction for warning interval (fore-period duration) with depression (warning interval effect is bigger in depressed group – the lines are further apart): this effect affects the motor response stage. Therefore we can conclude that this stage is impaired in the depressed group
• there is NO interaction between depression and signal intensity: the signal detection stage is not influenced

Question 22

Mental chronometry

Answer 22

measures the time course of mental operations in the human nervous system

Question 23

AFM in practice

Answer 23

• 2 factors F and G
  o F and G have additive effect: assume 2 stages
  o F and G interact: assume 1 stage
• Add a Factor Ho Test interaction H * F and H * G
  o H additive with both F and G: assume 3 stages
• assume / ‘discover’ extra stage for each factor who’s effects are additive with other factors

Question 24

RT: effects of practice

Answer 24

• After more practice
  o Shorter RT, fewer errors
  o Less variability across trials

Question 25

4 mental operations of memory search task

Answer 25

1. Encode. The participant must identify the visible target
2. Compare. The participant must compare the mental representation of the target with the representations of the items in memory.
3. Decide. The participant must decide whether the target matches one of the memorized items.
4. Respond. The participant must respond appropriately for the decision made in step 3.

Question 26

AFM challenges

Answer 26

-We need to accept H0:
If one factor has small effects at all levels of the other factor, it doesn’t mean that we have independent stages simply because there is no significant interaction.
 We don’t actually know if there are additive effects, we just know that there is no interaction because we accept the H0 Stage

• robustnes
• Stages not sequential: There are circumstances in which the nature of the factors is such that they plausibly affect two stages that are logically not sequential (i.e. factors that work on different features of the stimulus). If those features can be processed in parallel, then the stages would show temporal overlap, and RT would be shorter than the sum of stage durations, clearly violating AFM assumptions. We would then miss the existence of 2 separate stages.

Question 27

a 2 choice rt task

Answer 27

A 2-Choice RT task. The participant is asked for a speeded left button press if an ‘A’ is presented, and a right button press if a ‘B’ is presented.

Question 28

Donders ABC task types

Answer 28

 A = simple RT

 B = 2-choice RT: 2 buttons,
hit left when you see one
stimulus, right when you see the other

 C = go-nogo task / disjunctive RT (stimulus discrimination but no response selection is required because the response to be given is known in advance): 1 button, hit when you see one stimulus, withhold when you see the other

Question 29

Sternberg

Reaction time increases with set size, indicating

Answer 29

the target letter must be compared with the memory set sequentially (only one letter at a time) rather than in parallel / simultaneously. If the comparison process would be parallel, then it wouldn’t have mattered how many items there are in the memory set.

Question 30

prblem of strop task

Answer 30

we have multiple mental representations that are activated at the same time

colour and name

Question 31

2-choice rt task

Answer 31

A 2-Choice RT task. The participant is asked for a speeded left button press if an ‘A’ is presented, and a right button press if a ‘B’ is presented

Question 32

Analysis at level 1: A few numbers to characterize the condition and participant

Answer 32

accuracy: only analyse valid trials (no practice and warm-up). Count number of correct responses and compute a percentage (per condition per participant).

reaction time

Outliers: inattentiveness can cause large RT that skew the meanRT, standard deviation and variance. Outliers can also be extremely fast responses. To prevent outliers, one should stress the importance of consistency in instructions to participants and give feedback.

Question 33

Outliers and cognitive neuroscience:

Answer 33

Outliers and cognitive neuroscience: If EEG or fMRI have been collected along with the RT, final analyses should base on exactly the same selection of trials used for RT data.

This entails removing trials with RT-outliers from neuroimaging data and can also entail deleting RTs from trials that are rejected from EEG or fMRI.

Question 34

analysis at level 2

Answer 34

Statistical testing:
For each condition, the mean across participants is computed and displayed in a table or a graph. The conditions serve as ‘repeated measures’ or ‘dependent’ observations.

Outliers at level 2: removing outliers at this stage is not wise because now, any effect can be made significant by removing participants that don’t show the effect. omitting participants without giving a good rationale can even be considered scientific fraud. If there are good reasons (non-compliance, misunderstanding of instructions, inattentiveness, etc.) participants can be omitted from the results

Question 35

SMULDERS – COMMENTARY ON BONIN-GUILLAUME et al.: AN ADDITIVE FACTOR ANALYSIS OF THE EFFECT OF DEPRESSION ON THE REACTION TIME OF OLD PATIENTS

AFM model suggestions

Answer 35

• incompatible stimulus-response mapping was more error prone than the compatible one
• results show an additive pattern of the effects of signal intensity, stimulus–response mapping and foreperiod duration which is not contradicted by the pattern of results obtained on the RT variance
• thus = successfully manipulated three independent stages

o the pre-processing stage affected by visual intensity

o the response selection stage affected by the compatibility of the stimulus–response mapping

o motor adjustment stage affected by the duration of the foreperiod

Question 36

SMULDERS – COMMENTARY ON BONIN-GUILLAUME et al.: AN ADDITIVE FACTOR ANALYSIS OF THE EFFECT OF DEPRESSION ON THE REACTION TIME OF OLD PATIENTS

summary findings

Answer 36

• AFM is valid for studying depression in old participants  Indeed, besides the mere replication of a lack of interaction between the manipulated task factors, this pattern suggests that the structural organization of stimulus pre-processing, response selection and motor adjustment is similar in depressed and non-depressed participants, which was a prerequisite for using the AFM in old depressed subjects

• results indicate that depression interacts with foreperiod duration on RT and with stimulus–response compatibility on the error rate,
therefore motor adjustment and response selection are functional targets of depression in the elderly (main effect of foreperiod duration)

• depression and stimulus intensity display additive effects on RT (depression spares the stage of stimulus processing) (main effect on stimulus intensity)
• main effect of response selection

• interaction for warning interval (fore-period duration) with depression (warning interval effect is bigger in depressed group – the lines are further apart): this effect affects the motor response stage. Therefore we can conclude that this stage is impaired in the depressed group
• interaction of motor processing in depressed group (smaller effect of compatibility in depressed group)
• there is NO interaction between depression and signal intensity: the signal detection stage is not influenced
Overall conclusion: motor processes might be impaired in depressed elderly