A role for attentional bias in cognitive deficits in chronic pain?

<p>This thesis extends current understanding of cognitive deficits in people with chronic pain, specifically those related to attention. Researchers have proposed that attentional capacity is allocated to pain sensation, and away from current tasks and goals, leading to broad cognitive deficits (deficit-view). However, an attentional bias to pain-related information has also been observed in people with chronic pain, suggesting that attention is motivated towards information in the environment that is pain-related, and away from information that is not. Such an attentional bias away from information not related to pain may contribute to the cognitive deficits observed on tasks using neutral stimuli (motivated attention hypothesis). In testing the deficit-view and motivated attention accounts of cognitive deficits in chronic pain, I focused on how people attend to rapidly presented information (temporal attention) and the ability to control attention in the face of distraction. To assess how chronic pain affects temporal attention, I used a phenomenon known as the attentional blink, which is a failure to detect a second target that appears soon after a first. Participants viewed a stream of briefly displayed words in which two target words (indicated by their colour) were embedded, with a manipulation of the time between the first and second target. They were required to report the two targets. In one experiment the first target was either pain-related or neutral (to assess how pain-relatedness affects the induction of the blink), and in other experiments this manipulation was applied to the second target (to assess how pain-relatedness affects how targets overcome the blink). In undergraduate participants, both induction and overcoming of the attentional blink was modulated by pain-relatedness. I then compared the effects of manipulating the second target in people with and without chronic pain. If people with chronic pain have general deficits in temporal attention, a deeper attentional blink (relative to control participants) for both kinds of targets should be observed. If motivated attention describes processing in people with chronic pain, a shallower attentional blink for pain related targets than neutral targets (an attentional bias) should be observed. Critically, this bias should be larger in participants with chronic pain. Contrary to both the deficit and motivated attention views, the attentional blink in participants with chronic pain did not differ from that in controls for either pain-related or neutral targets. Furthermore, neither group showed an attentional bias for pain-related targets, and a follow-up experiment failed to replicate the attentional bias observed in undergraduate students as well. Collectively, these findings suggested that attentional bias, as assessed by modulation of the attentional blink, was not reliable. A stronger test of the deficit-view and motivated attention hypothesis was needed. I shifted focus to another attentional domain, the control of distraction. To assess how chronic pain affects attentional control, I used an emotional distraction task, in which participants identified a target letter in an array that flanked irrelevant distractor images that were either intact or scrambled. Intact images depicted either extreme threat to body-tissue, or benign scenes. Distraction is indicated by slowing on intact relative to scrambled distractor trials. If people with chronic pain have general deficits in attentional control, they should show greater distraction from both kinds of images (relative to controls). If motivated attention describes processing in people with chronic pain, greater distraction from body-threat images than neutral images (relative to controls) should be observed. While all participants were more distracted by images depicting extreme threat to body-tissue, people with chronic pain were not more distracted than control participants for either image type. Findings fail to support either a deficit or motivated attention view of attentional control in chronic pain. Although these experiments do not provide evidence that chronic pain affects attentional processing, across experiments people with chronic pain reported that they experience deficits in attention, and they showed behavioural evidence of psychomotor slowing. These findings suggest that, as is repeatedly reported in the literature, people in chronic pain feel like they have attentional deficits, and that some aspects of cognitive and/or motor processing are impacted. Careful consideration is given to what specific cognitive functions might be impaired in chronic pain. The outcome of this discussion suggests pertinent research directions to further understanding of cognition in chronic pain experience.</p>

A role for attentional bias in cognitive deficits in chronic pain?

<p>This thesis extends current understanding of cognitive deficits in people with chronic pain, specifically those related to attention. Researchers have proposed that attentional capacity is allocated to pain sensation, and away from current tasks and goals, leading to broad cognitive deficits (deficit-view). However, an attentional bias to pain-related information has also been observed in people with chronic pain, suggesting that attention is motivated towards information in the environment that is pain-related, and away from information that is not. Such an attentional bias away from information not related to pain may contribute to the cognitive deficits observed on tasks using neutral stimuli (motivated attention hypothesis). In testing the deficit-view and motivated attention accounts of cognitive deficits in chronic pain, I focused on how people attend to rapidly presented information (temporal attention) and the ability to control attention in the face of distraction. To assess how chronic pain affects temporal attention, I used a phenomenon known as the attentional blink, which is a failure to detect a second target that appears soon after a first. Participants viewed a stream of briefly displayed words in which two target words (indicated by their colour) were embedded, with a manipulation of the time between the first and second target. They were required to report the two targets. In one experiment the first target was either pain-related or neutral (to assess how pain-relatedness affects the induction of the blink), and in other experiments this manipulation was applied to the second target (to assess how pain-relatedness affects how targets overcome the blink). In undergraduate participants, both induction and overcoming of the attentional blink was modulated by pain-relatedness. I then compared the effects of manipulating the second target in people with and without chronic pain. If people with chronic pain have general deficits in temporal attention, a deeper attentional blink (relative to control participants) for both kinds of targets should be observed. If motivated attention describes processing in people with chronic pain, a shallower attentional blink for pain related targets than neutral targets (an attentional bias) should be observed. Critically, this bias should be larger in participants with chronic pain. Contrary to both the deficit and motivated attention views, the attentional blink in participants with chronic pain did not differ from that in controls for either pain-related or neutral targets. Furthermore, neither group showed an attentional bias for pain-related targets, and a follow-up experiment failed to replicate the attentional bias observed in undergraduate students as well. Collectively, these findings suggested that attentional bias, as assessed by modulation of the attentional blink, was not reliable. A stronger test of the deficit-view and motivated attention hypothesis was needed. I shifted focus to another attentional domain, the control of distraction. To assess how chronic pain affects attentional control, I used an emotional distraction task, in which participants identified a target letter in an array that flanked irrelevant distractor images that were either intact or scrambled. Intact images depicted either extreme threat to body-tissue, or benign scenes. Distraction is indicated by slowing on intact relative to scrambled distractor trials. If people with chronic pain have general deficits in attentional control, they should show greater distraction from both kinds of images (relative to controls). If motivated attention describes processing in people with chronic pain, greater distraction from body-threat images than neutral images (relative to controls) should be observed. While all participants were more distracted by images depicting extreme threat to body-tissue, people with chronic pain were not more distracted than control participants for either image type. Findings fail to support either a deficit or motivated attention view of attentional control in chronic pain. Although these experiments do not provide evidence that chronic pain affects attentional processing, across experiments people with chronic pain reported that they experience deficits in attention, and they showed behavioural evidence of psychomotor slowing. These findings suggest that, as is repeatedly reported in the literature, people in chronic pain feel like they have attentional deficits, and that some aspects of cognitive and/or motor processing are impacted. Careful consideration is given to what specific cognitive functions might be impaired in chronic pain. The outcome of this discussion suggests pertinent research directions to further understanding of cognition in chronic pain experience.</p>

Electric signal synchronization as a behavioural strategy to generate social attention in small groups of mormyrid weakly electric fish and a mobile fish robot

African weakly electric fish communicate at night by constantly emitting and perceiving brief electrical signals (electric organ discharges, EOD) at variable inter-discharge intervals (IDI). While the waveform of single EODs contains information about the sender’s identity, the variable IDI patterns convey information about its current motivational and behavioural state. Pairs of fish can synchronize their EODs to each other via echo responses, and we have previously formulated a ‘social attention hypothesis’ stating that fish use echo responses to address specific individuals and establish brief dyadic communication frameworks within a group. Here, we employed a mobile fish robot to investigate the behaviour of small groups of up to four Mormyrus rume and characterized the social situations during which synchronizations occurred. An EOD-emitting robot reliably evoked social following behaviour, which was strongest in smaller groups and declined with increasing group size. We did not find significant differences in motor behaviour of M. rume with either an interactive playback (echo response) or a random control playback by the robot. Still, the robot reliably elicited mutual synchronizations with other fish. Synchronizations mostly occurred during relatively close social interactions, usually when the fish that initiated synchronization approached either the robot or another fish from a distance. The results support our social attention hypothesis and suggest that electric signal synchronization might facilitate the exchange of social information during a wide range of social behaviours from aggressive territorial displays to shoaling and even cooperative hunting in some mormyrids.

Visuals and attention to earnings news on twitter

We propose the visual attention hypothesis that visuals in firm earnings announcements increase attention to the earnings news. We find that visuals in firms’ Twitter earnings announcements are associated with more retweets, consistent with greater user engagement with announcements that have visuals. This result holds for earnings tweets sent by the same firm and on the same day in firm-level and tweet-level analyses. Consistent with managerial opportunism, firms are more likely to use visuals in their earnings tweets when performance is good but less persistent. Consistent with visuals increasin g investor attention, the initial return response to earnings news is stronger and the post-announcement response is lower when visuals are used. Our evidence of a post-announcement return reversal indicates that visuals can be a double-edged sword. Furthermore, the higher earnings response coefficient from visuals is more pronounced on days with high investor distraction (when many other firms are also announcing earnings). Graphical abstract

Advertising, Attention, and Stock Returns

This paper studies the effect of advertising on stock returns both in the short and in the long run. We find that a greater amount of advertising is associated with a larger stock return in the advertising year but a smaller stock return in the year subsequent to the advertising year, even after we control for other price predictors, such as size, book-to-market, and momentum. We conjecture that advertising affects stock returns by attracting investors’ attention to the firm’s stock. Stock price increases in the advertising year due to the attracted attention, but decreases in the subsequent year as the attracted attention wears out over time. We test this investor attention hypothesis and document consistent findings. We find that advertising increases a firm’s visibility among investors in the advertising year. We further find that the negative effect of advertising on the long-run reversal in stock returns is more pronounced if a firm attracts greater investor attention in the advertising year, or if investors face a larger cost of short selling the firm’s stock. It is also more pronounced for small firms, value firms, and firms with poor ex-ante stock or operating performance. Finally, we find that the effect of advertising on future stock returns is stronger when advertising increases compared to the case when advertising decreases.

Intraday Return Reversals: Empirical Evidence from the Korean ETF Market

We find that the overnight returns of Korean exchange-traded index funds (ETFs) are significantly positive, whereas the subsequent intraday returns are negative. These intraday return reversals are caused by relatively higher opening prices than the closing prices. In the Korean ETF market, where institutional investors are dominant participants, the return reversals are not explained by the attention hypothesis as in Berkman et al. [1]. Hence, we investigate whether the disagreement hypothesis can explain return reversals. Under the disagreement situations between positive and negative traders at the open, positive traders can have a positive influence on the ETF prices by increasing their investments. However, negative traders, who give up investments due to limited short selling opportunities in the ETF market, have no effects on the prices. Comparing ETF markets with KOSPI 200 Futures where there are no restrictions on short selling, we find that short selling constraints are significant factors for the return reversals. This implies that disagreement among the investors can cause return reversals even in the markets without noise traders. Using unique Korean market data, we conclude that return reversals cannot be completely explained by the attention hypothesis, and that disagreement among investors is also a significant factor for the return reversals. This study contributes to the existing literature by showing that the attention hypothesis does not explain return reversals in the ETF market completely, and suggesting the disagreement hypothesis as an alternative.

Release from output interference in recognition memory: A test of the attention hypothesis

Retrieval results in both costs and benefits to episodic memory. Output interference (OI) refers to the finding that episodic memory accuracy decreases with increasing test trials. Release from OI is the restoration of original accuracy at some point during the test. For example, a release from OI in recognition memory testing occurs when the semantic similarity between stimuli decreases midway through testing, suggesting that item representations stored on early trials cause interference on tests occurring on later trials to the extent that the earlier items share features with the latter items. In two recognition memory experiments, we demonstrate release from OI for words and faces. We also test whether release from OI is the result of interference or is due to a boost in attention caused by reorienting to a novel stimulus type. A test for the foils presented during the initial test list supports the interference account of OI. Implications for models of memory are discussed.