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Visual Attention - Y2 - Coggle Diagram

- - - - Neural activity in the brain associated with seeing a stimulus (Gilhooly et al, 2022):
        
        Stimulus -> 40ms - primary visual cortex responds -> 80ms - most secondary visual areas are activated -> 120 ms - activations can be found throughout the cortex
        
        Reduction in neural responses has been shown when a non-preferred stimulus is presented in the same receptive field as a preferred one
        
        Feedforward processing describes a bottom-up process where lower levels of a network progressively stimulate higher levels of the network
        
        Recurrent processing within a network involves computations that occur in a cyclical fashion
- - - - Visual search (Gilhooly et al, 2022):
        
        This experimental approach is concerned with understanding how we use attention to search for a target in a visual display
        
        What influences visual search time (Wickens, 2021) -
        -> Properties of the search field - number of targets, distractors and background clutter
        -> Discriminability between targets and distractors
        -> How we make a search more rapid (Wickens, 2021)
        --> Fewer distractors (smaller N)
        --> The target is uniquely defined by one level on only one sensory continuum
        --> The level on the continuum defining the target is not similar to those levels of the non-targets (distractors)
        --> The distractors are homogenous
        --> The target possesses a unique feature (rather than uniquely lacking the feature)
        --> The target (not the distractor) differs from a default value (like verticality)
        --> The target is novel and only one target needs to be sought at a time
        
        Feature integration theory (Treisman & Gelade, 1980) - model 1:
        
        Both the target and the distractor are composed of visual features such as shape, size and colour
        
        Target is recognised by two processes -
        -> Preattentive process - requires searching the entire array, it can independently examine features such as colour and form, and if a target can be identified by a single feature, then this process can lead to recognition
        -> Focused attention - used when recognition is dependent on combining multiple features
        
        Preattentive -
        -> Input -> analysis is independent and simultaneous of each feature
        
        Focused attention -
        -> Use of attention to combine these different features and bind them together -> recognition
        -> Binding problem - describes the issue that although perception works via analysis of separate perceptual features, our subjective experience has all these features bound together
        
        Illusory conjunctions (Treisman & Schmidt, 1982)
        
        Confusions between features of objects - they occur when attention is diverted or overloaded
        
        Guided search model (Wolfe, 1994; Wolfe et al, 2011) - model 2: - Similar to the FIT, focused attention is featured in the selective pathway, and the preattentive stage remains as a form of early visual processing
        
        However, it differs from the FIT because it proposes the preattentive stage as an analysis that forms an abstract representation where particular features can be used to guide attention at the point of the attentional bottleneck -> makes a selective pathway for binding and recognition, where it takes the relevant features (alternative non-selective pathway)
        
        We already have an abstract representation of the object, which aids our visual search
        
        Additionally, it includes a non-selective pathway that informs the likelihood of what scene is being viewed
        
        Distributed attention - is reminiscent of preattentive vision and allows rapid statistical analysis of the entire scene
        
        Visual search conclusions (Gilhooly et al, 2022) -
        
        FIT and the Guided Search model have been explored through quantitative models that predict how efficient a search will be considering both targets and distractors
        
        However, these models have been challenged for two main reasons -
        -> It seems like a number of fixations is a better predictor of performance than number of test items (Hulleman & Olivers, 2017)
        -> These models have poor ecological validity - they rely on controlled visual displays that are artificial (importance of natural scenes); scenes are not static when we search
      - Inhibition of return (Gilhooly et al, 2022);
        
        This mechanism promotes searching novel locations rather than ones which have already been examined
        
        Posner’s spatial cueing task -
        -> Traditionally, it involves presenting a cue in one of two peripheral locations, followed by a target at one of two - the effect is observed when the time interval between the cue and target is longer than 250-500ms
        -> This effect has been interpreted as attention being drawn to the location of this cue, but attention abandons this location after a short period of time and avoids returning to it (Dukewich & Klein, 2015)
        
        Conclusions -
        
        This method remains a popular one to explore visual attention, but there are issues with its implementation
        
        An important challenge is that there are a variety of views regarding its causes and effects, their linking mechanisms and the range of phenomena that have been labelled as inhibition of return - poor conceptualisation of the theory
        
        A way forward when using this method is for researchers to be as explicit as possible when defining the type of inhibition of return that they are exploring
      - Attentional blink (Gilhooly et al, 2022)
        
        If we are watching a sequence of rapidly presented visual displays, the second of two targets cannot be identified when its presentation is close in time to that of a first target
        
        Causes of attentional blink (Nieuwenstein et al, 2009)
        -> Attentional blink can occur even in the absence of distractors, with two letter targets separated by a blank interval
        -> Their work suggested that the root cause of the blink lies in the difficulty of engaging attention twice within a short period of time for two temporally discrete time events
        
        Distractor based explanations and delayed reengagement -
        -> Impairment for identification of second target separated by blank interval is attenuated when the inter-target interval is filled with other target items or precured by an additional target
        -> These findings show that the root cause of the blink lies in the difficulty of engaging attention twice within a short period of time for two temporally discrete target events
        
        Conclusions - Dux & Marois, 2009 -
        
        It has been central in characterising the limits of human ability to consciously perceive stimuli distributed across time
        
        One of the most commonly used paradigms is the rapid serial visual representation paradigm
        
        There are many models used to explain the attentional blink, and it has been suggested that it reflects the competition between targets for attentional resources, not only for working memory encoding, episodic registration and response selection but also for the enhancement of target representations and inhibition of distractors
      - Discussion of each approach -
        Visual Search -
        
        Uses simplified stimuli that might not reflect the complexity of real-world settings
        
        There are individual differences in visual search strategies and abilities which makes findings hard to generalise
        
        The cognitive load in maintaining attention and memory during tasks impacts performance
        
        Fixations are a valuable predictor, but other aspects are overlooked
        
        Inhibition of return -
        
        Timing of inhibitory process can vary which makes it difficult to temporarily identify duration and onset
        
        Current conceptualisations are limited by existing research
        
        Is there more happening at a cognitive level that confounds this effect?
        
        Attentional blink -
        
        Is it showing disrupted attentional engagement?
        
        Is it showing because there are multiple attentional demands?
        
        Summary of each approach -
        
        Visual search focuses on spatial distribution of attention, and we use it on a daily basis and there are significant individual differences
        
        Inhibition return - focuses on spatial attention and temporal inhibition to a location, with tasks being used varying greatly
        
        Attentional blink - focuses on temporal gaps in attention when processing a sequence of stimuli - effects are consistent in RSVP tasks mostly