Episodic Indexing: A Model of Memory for Attention Events

People often remember what they attend to in the world. Such memory can be cast as a kind of mental catalog or index of attended objects. To investigate how such an index is acquired and used, protocol data were collected from a programmer who scrolled to off-screen objects from time to time as she worked. These protocol data were modeled using Soar, which constrains how the index is constructed. In the model, an index entry is an episodic trace encoded during attention. The trace associates the attention event with a time symbol denoting the event's occurrence. Later, the model can ask itself whether it saw that object by calling to mind an image of the attention event. If this image retrieves a time symbol, then the model infers that the object exists and can reason about bringing the object back into view. Episodic indexing is a theory of these encoding and retrieval processes. It posits that information about attention events is encoded automatically, but that retrieval requires effort and knowledge. Episodic indexing is congruent with a range of results on episodic and temporal codes and recognition and recall processes. It incorporates source monitoring (Johnson, Hashtroudi, & Lindsay, 1993) and is a simple and pervasive form of long-term working memory (Ericsson & Kintsch, 1995).     

An Analysis of the Time Course of Lexical Processing During Reading

Reingold, Reichle, Glaholt, and Sheridan (2012) reported a gaze‐contingent eye‐movement experiment in which survival‐curve analyses were used to examine the effects of word frequency, the availability of parafoveal preview, and initial fixation location on the time course of lexical processing. The key results of these analyses suggest that lexical processing begins very rapidly (after approximately 120 ms) and is supported by substantial parafoveal processing (more than 100 ms). Because it is not immediately obvious that these results are congruent with the theoretical assumption that words are processed and identified in a strictly serial manner, we attempted to simulate the experiment using the E‐Z Reader model of eye‐movement control (Reichle, 2011). These simulations were largely consistent with the empirical results, suggesting that parafoveal processing does play an important functional role by allowing lexical processing to occur rapidly enough to mediate direct control over when the eyes move during reading.     

Delayed Match Retrieval: a novel anticipation‐based visual working memory paradigm

We tested 8‐ and 10‐month‐old infants’ visual working memory (VWM) for object‐location bindings – what is where – with a novel paradigm, Delayed Match Retrieval, that measured infants’ anticipatory gaze responses (using a Tobii T120 eye tracker). In an inversion of Delayed‐Match‐to‐Sample tasks and with inspiration from the game Memory, in test trials, three face‐down virtual ‘cards’ were presented. Two flipped over sequentially (revealing, e.g. a swirl pattern and then a star), and then flipped back face‐down. Next, the third card was flipped to reveal a match (e.g. a star) to one of the previously seen, now face‐down cards. If infants looked to the location where the (now face‐down) matching card had been shown, this was coded as a correct response. To encourage anticipatory looks, infants subsequently received a reward (a brief, engaging animation) presented at that location. Ten‐month‐old infants performed significantly above chance, showing that their VWM could hold object‐location information for the two cards. Overall, 8‐month‐olds’ performance was at chance, but they showed a robust learning trend. These results corroborate previous findings (Kaldy & Leslie, 2005; Oakes, Ross‐Sheehy & Luck, 2006) and point to rapid development of VWM for object‐location bindings. However, compared to previous paradigms that measure passive gaze responses to novelty, this paradigm presents a more challenging, ecologically relevant test of VWM, as it measures the ability to make online predictions and actively localize objects based on VWM. In addition, this paradigm can be readily scaled up to test toddlers or older children without significant modification.     

Predicting Treatment Outcomes From Internet-Based Cognitive Behavior Therapy for Obsessive–Compulsive Disorder

Internet-based cognitive-behavioral therapy (ICBT) with therapist support shows promise as a treatment for obsessive-compulsive disorder (OCD). Yet, not all patients respond to ICBT. It is therefore important to identify predictors of ICBT outcomes to determine who is likely to benefit. Relative to the large literature on predictors of outcomes for in-person CBT for OCD, very few studies have investigated ICBT predictors. Therefore, we analyzed predictors of outcome in an open trial (n = 30) of ICBT for OCD using the OCD-NET platform, which consists of 10 online modules delivered with therapist support. The Yale-Brown Obsessive-Compulsive Scale (YBOCS) was administered by independent raters as the primary outcome measure at baseline and posttreatment. In this sample, greater baseline OCD severity and OCD-related avoidance behaviors were associated with higher end-state OCD symptoms (i.e., poorer outcome). Patients with a past history of face-to-face CBT for OCD also had worse outcomes. Although these results require replication, these factors may identify individuals at risk for poor ICBT outcomes.     

Explicationist Epistemology and the Explanatory Role of Knowledge

Journal for General Philosophy of Science - It has been argued that much of contemporary epistemology can be unified under Carnap’s methodology of explication, which originated in the...     

Motion integration during motion aftereffects

The perceived global motion of a stimulus depends on how its different local motion-direction vectors are distributed in space and time. When they are explicitly co-localized, as in the case of locally paired motion, competitive motion integration mechanisms produce a unitary global motion direction determined by their vector average. During motion aftereffects induced by simultaneous adaptation to multiple motion directions, just as in the case of locally paired motion, different directional signals originate simultaneously from exactly the same position in space. Therefore, the perceived global motion direction during motion aftereffects results from local vector averaging of the co-localized motion-direction signals induced by adaptation.     

The emergence of frequency effects in eye movements

A visual search experiment employed strings of Landolt Cs to examine how the gap size of and frequency of exposure to distractor strings affected eye movements. Increases in gap size were associated with shorter first-fixation durations, gaze durations, and total times, as well as fewer fixations. Importantly, both the number and duration of fixations decreased with repeated exposures. The findings provide evidence for the role of cognition in guiding eye-movements, and a potential explanation for word-frequency effects observed in reading.