Free recall is a basic paradigm that has long been used to study human memory, and which was central to the verbal learning tradition in early cognitive psychology (e.g. Glanzer & Cunitz, 1966; Murdock, 1962; Postman & Phillips, 1965). In a free recall task, a subject is presented a list of to-be-remembered items, one at at time. For example, an experimenter might read a list of 20 words aloud, presenting a new word to the subject every 4 seconds. At the end of the presentation of the list, the subject is asked to recall the items (e.g., by writing down as many items from the list as possible).

• Postman And Phillips Serial Position Effect Theory Test
• Serial Position Effect Activity
• Serial Position Effect Test

It is called a free recall task because the subject is free to recall the items in any order that he or she desires.The free recall task is of interest to cognitive science because it provided some of the basic information used to decompose the mental state term 'memory' into simpler subfunctions ('primary memory', 'secondary memory'). This is because the results of a free recall task were typically plotted as a serial position curve. This curve exhibited a recency effect and a primacy effect. The behavior of these two effects provided support to the hypothesis that the free recall task called upon both a short-term and a long-term memory.References:. Glanzer, M., & Cunitz, A.

Two storage mechanisms in free recall. Journal of Verbal Learning and Verbal Behavior, 5(4), 351-360. Murdock, BB (1962).

Postman And Phillips Serial Position Effect Theory Test

'The serial position effect of free recall'. Psychological Review, 65, 482–488. Postman, L., & Phillips, L. Short-term temporal changes in free recall. Quarterly journal of experimental psychology, 17, 132-138.(Revised April 2010).

1., 2 and 1. 1Department of Psychology, Temple University, Philadelphia, PA, USA. 2Department of Psychology, Princeton University, Princeton, NJ, USAOngoing debate surrounds the capacity and characteristics of the focus of attention. The present study investigates whether a pattern of larger recency effects and smaller primacy effects reported in previous working memory studies is specific to task conditions used in those studies, or generalizes across manipulations of task-demand. Two experiments varied task-demands by requiring participants to remember lists of letters and to then respond to a subsequent two-item probe by indicating either the item that was presented later in the list (judgment of recency) or the item was presented earlier (judgment of primacy). Analyses tested the prediction that a WM task emphasizing later items in a list (judgment of recency) would encourage exaggerated recency effects and attenuated primacy effects, while a task emphasizing earlier items (judgment of primacy) would encourage exaggerated primacy effects and attenuated recency effects.

Behavioral results from two experiments confirmed this prediction. In contrast to past studies, fMRI contrasts revealed no brain regions where activity was significantly altered by the presence of recency items in the probe, for either task condition. However, presence of the primacy item in the probe significantly influenced activity in frontal lobe brain regions linked to active maintenance, but the location and direction of activation changes varied as a function of task instructions.

In sum, two experiments demonstrate that the behavioral and neural signatures of WM, specifically related to primacy and recency effects, are dependent on task-demands. Findings are discussed as they inform models of the structure and capacity of WM. IntroductionA wide variety of research suggests strict limits on the mind's ability to maintain and manipulate information over the short term—an ability often referred to as working memory (WM; e.g.,;; ). While researchers generally agree on the existence of such capacity limits, ongoing debate surrounds the precise structure and function of human memory, including the specific properties and capacity limits of WM (; ). The present paper explores one explanation for divergent conclusions about the architecture and capacity of WM, and concentrates on the contributions of the “focus of attention” (FOA, or the most immediate state of WM) to WM capacity. Using both behavioral and neuroimaging (fMRI) methods, we test the hypothesis that subtle features of the tasks used to probe WM function (e.g., task instructions and response requirements) can lead to important performance differences (e.g., which item in a list is remembered the quickest), fundamental changes in the pattern of brain activity evoked by the WM task, and ultimately, to different conclusions about the FOA and its involvement in WM.A set of recent fMRI studies inform our approach (;,;, ).

Each of these studies set out to test theoretical claims about WM by comparing the brain activation patterns associated with retrieval of items from different serial positions in a list, an idea based on earlier behavioral research (; ). Memory for lists of items almost always yields evidence of primacy and recency effects—elevated memory for the earliest and latest items compared to middle items (; ).

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Trial sequences were constructed prior to the experiment in order to control the serial position of the correct and incorrect probes. The two items contained in each probe were counterbalanced so that in half of trials the correct answer was on presented on the right side of the screen and half the trials it was on the left side of the screen. Tasks were constructed so that each of the four possible correct serial positions was probed as the correct response 24 times, resulting in 96 trials per task, and the serial position of the incorrect probe was also balanced. Trials were blocked by task so that subjects would not be required to rapidly switch task-demands between trials.

Task order was counterbalanced across subjects. Within each task block of 96 trials, the order of trials probing different serial positions was randomized, as was the identity of the letters presented in each serial position. In an attempt to encourage verbal phonological coding, and to discourage simple perceptual matching of the encoded and probed items, capital letters were used for item presentation while lowercase letters were used for retrieval probes. ProcedureIn each task, subjects completed 5 practice trials, followed by 96 actual trials. Each task block lasted roughly 15 min (each trial was 6.75 s, and the inter-trial intervals were subject-paced), and subjects were allowed to pause between blocks. Data analysisAll significance tests were conducted from the perspective of null hypothesis significance testing (NHST) and were non-directional with alpha = 0.05.

To supplement the NHSTs, effect size estimates were calculated using partial eta-squared. Behavioral measures included both accuracy and reaction times, but reaction time on correct trials was the main outcome of interest for examining serial position dynamics. Serial position analyses proceeded with two separate methodologies for defining primacy and recency trials and calculating primacy and recency effects.Serial position analysis, method 1: primacy and recency assigned according to the position of the correct response. The first method of analysis was based on and earlier investigations of JOR (see ), and involved averaging of trials according to the serial position of the correct response.

Here, primacy and recency trials were defined by whether the earliest or latest possible correct response was included in the probe. In JOR, primacy trials were trials where the correct response was item 2 (1–2 probes), middle trials were trials where the correct response was item 3 or 4 (1–3, 1–4, 2–3, 2–4, and 3–4 probes), and recency trials were trials where the correct response was item 5 (1–5, 2–5, 3–5, and 4–5 probes). Analysis of reaction times revealed a main effect of task where JOR was slower than JOP F (1, 19) = 25.51, p. Average magnitude of primacy and recency effects in JOR and JOP. Error bars represent the standard error of the mean. Calculation of primacy and recency effects produces an index of the percent reaction time advantage for retrieval of the primacy/recency item when compared to retrieval of middle items. (A) Primacy and recency effects in JOR and JOP calculated using method 1.

Method 1 divides trials by the serial position of the correct probe item, and primacy and recency trials were defined by whether the earliest or latest possible correct response was the correct answer in the probe. (B) Primacy and recency effects in JOR and JOP calculated using method 2. Here, trials are divided by considering both items in the probe, and primacy and recency item trials are trials that include the earliest (primacy) or latest (recency) item. Primacy and recency assigned according to whether the first or last item was included in the probeA 2 by 4 repeated measures ANOVA examined the interaction of task-demand (JOR, JOP) and trial type (primacy trials, 1–2, 1–3, 1–4; recency trials, 5–4. 5–3, 5–2; middle trials, 2–3, 2–4, 3–4; and 1–5 trials) on reaction time for correct trials.

Serial Position Effect Activity

This ANOVA revealed a main effect of task where JOR was slower than JOP F (1, 19) = 23.82, p. Contrasts also compared the retrieval period of primacy and recency item probes to each other. The purpose of these contrasts was two-fold: to compare the neural mechanisms of retrieval of the earliest and latest items, and also to “complete the set” of comparisons between the three trial types (primacy item trials, middle item trials, and recency item trials). In each case, regions were very consistent between the primacy and recency probe trials, and only areas of the right occipital and fusiform gyrus (BA 17, 18) varied between primacy and recency item probes. In JOR, activity was higher for the primacy item probe than the recency item probe, while in JOP it was higher for the recency item probe than the primacy item probe.In order to more formally test whether task-demands affect the neural signature of serial position effects, ANOVAs comparing primacy and recency effects observed in each task were conducted. The first ANOVA included middle and recency trials (JOR: items 3, 4, 5; JOP: items 2, 3, 4) across task (JOR, JOP), while the second examined primacy and middle trials (JOR: items 2, 3, 4; JOP; 1, 2, 3) across task (JOR, JOP). The results of interest regarded the task by effect-type interaction.A single inferior frontal region (BA 9/44) showed a significant task by recency effect interaction.

The source of this interaction was explored through comparison of fMRI signal change (against baseline) in each of the serial positions of interest. However, contrasts revealed that neither JOR nor JOP showed a difference between the recency trial and the middle trials JOR: F (1, 27) = 2.32, p = 0.14, η 2 p = 0.08: JOP: F (1, 27) = 1.78, p = 0.20, η 2 p = 0.06. Instead this task by serial position interaction was driven by a difference between performance on middle trials that was found in JOR F (1, 27) = 20.60, p. Follow-up analyses in the MTL. The primary serial position comparisons in the present paper did not reveal differences in the MTL, and analyses of both the encoding-maintenance and retrieval periods compared to the ITI revealed lower activation during encoding-maintenance and retrieval than at rest. However, as we mentioned above, prior studies have found MTL differences using a variety of specific serial position contrasts. For examplecompared probes involving the first two items (in a 12 item list) to probes involving the last two items.

Serial Position Effect Test

To mirror this analysis on our shorter list, we compared probes involving the first two and last two possible correct items in both JOR (positions 2 and 3 against 4 and 5) and JOP (positions 1 and 2 against 3 and 4). Using a lowered uncorrected threshold of p.