Editing Animal cognition (section)

==== Divided attention ====
Attention is a limited resource and is not a none-or-all response:  the more attention devoted to one aspect of the environment, the less is available for others.<ref>{{cite journal | vauthors = Zentall TR | title = Selective and divided attention in animals | journal = Behavioural Processes | volume = 69 | issue = 1 | pages = 1–15 | date = April 2005 | pmid = 15795066 | doi = 10.1016/j.beproc.2005.01.004 | s2cid = 24601938}}</ref>  A number of experiments have studied this in animals. In one experiment, a tone and a light are presented simultaneously to pigeons.  The pigeons gain a reward only by choosing the correct combination of the two stimuli (e.g. a high frequency tone together with a yellow light).  The birds perform well at this task, presumably by dividing attention between the two stimuli.  When only one of the stimuli varies and the other is presented at its rewarded value, discrimination improves on the variable stimulus but discrimination on the alternative stimulus worsens.<ref>{{cite journal | vauthors = Blough DS | title = Attention shifts in a maintained discrimination | journal = Science | volume = 166 | issue = 3901 | pages = 125–6 | date = October 1969 | pmid = 5809588 | doi = 10.1126/science.166.3901.125 | bibcode = 1969Sci...166..125B | s2cid = 33256491}}</ref>  These outcomes are consistent with the notion that attention is a limited resource that can be more or less focused among incoming stimuli.